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  #126  
Old 02-14-2013, 12:40 PM
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Quote:
Originally Posted by OverLord View Post
While im not trying to argue with either of you and am more or less raising a question, If this is the case, why then will gas guns not work in cold weather? If your theory holds true, the pressure of a mag of gas in the cold and warm air should have no difference (Again, it could be another factor, please enlighten me if so)

In my personal experience, shooting any gas weapon in cold weather is generally a flop. After warming the mag in your pocket for a few seconds, you get a noticeable performance increase. From what i have been led to believe, the whole gas guns and cold weather concept stems from atmospheric pressure rather than gas temperature.

Again someone please explain to me why this effect happens and why P* are able to run cold weather better and not be subjected to temperature and pressure issues while other gas guns are horrendously effected.
Its because PolarStar runs off of HPA and is regulated. While most other gas guns are not regulated. High Pressure Air
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Last edited by Fallen Warrior Airsoft; 02-14-2013 at 12:46 PM.
  #127  
Old 02-14-2013, 12:41 PM
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Quote:
Originally Posted by Darkstar View Post
The actual output of any gun can be easily measure at the muzzle with a chrono, so long as you can calculate for BB weight. The barrel lenth, diameter air nozzle, etc, have no impact whatsoever on whatever the chrono measurement is at the muzzle. Sure, those variables have performance values to get the muzzle velocity up to a certain level, but you can build guns that shoots 400FPS a variety of ways, but they all shoot 400FPS, and that velocity is what is used to calculate energy for the projectile, so velocity is really the only factor. There is no need for any charts with regard to a chrono station. EO's keep things simple and fair. Everyone puts in a few .20's, shoots through the chrono, and makes sure they are at 400fps or less. If everyone wants to tune their guns to 400fps, then that's fine, and then everyone would be on the exact same level. But there are going to be people shooting 350fps or maybe even 300.
And this is exactly the problem... We can chrono all guns at the 400 fps limit with .20's but as soon as people put a heavier weight bb in their guns... it actually changes their joule rating which is why we use the FPS limit in the first place.

And with P*'s because they are so efficient, they experience a greater joule increase because their FPS isnt dropped as much by using a heavier bb as say your standard or slightly customed AEG. And GBBR do the same, just at a lessor degree.

So without asking the GBBR guys and P* guys to go back and adjust their PSI to compensate, they are actually firing a gun that could be outside of the joule parameters established by the .2 @400 FPS or 1.487(Thanks Swervin! haha) that the field established.

I hope this makes sense.
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  #128  
Old 02-14-2013, 12:41 PM
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Quote:
Originally Posted by Jonezy
It goes beyond feelings and into putting PolarStar users at a distinct, unfair disadvantage to everyone else. The numbers are all there to support it. There's not much more we can do to help you read and interpret data at this point. Why don't you head on over to the PolarStar Talk forums and see what that community of PolarStar users has to say about your proposals? Or do you already know what will happen if they see what you're trying to do?
I've seen you chart 24 shots with your polar star. Enough for you to prove a point here in internet land, not enough for us to use this as a safety standard for events across the state. Let's do more of this and perhaps create your own Airsoft Trajectory Project for Polarstars. Let's get that bad boy pier-reviewed - not the worst use of time for an aspiring engineer.

Now I've been talking with Yawger on this - and the Xcotech chronograph looks like a promising solution. You can key in the bb weight and it will automatically spit out joules and even ROF when you check a gun so it would reduce a lot of headache at the chrono line.

Quote:
Originally Posted by Jonezy
Would it help if someone were to put together a reference sheet with all the different weights of BBs and what FPS they need to stay under with those BBs to stay under the limit?
A chronograph that calculates on the fly would be more reliable, but I don't see why this couldn't be an option especially for if we got ourselves into the business of trying to find out the weight of a mystery bb.


Quote:
Originally Posted by nhviper
You are blatantly ignoring the fact that airsoft if about fun. If you are essentially giving everyone else an unfair advantage by not listening to the data and input you are being spoon fed on this thread, then where is the fun for those of us who have and who are going to be investing in a Polarstar rig?
What I'm saying is that I would like to see more data, but I personally will not take the time to commission a full study on this. If a few zealous P* users want to do this, I'm all for it.

Quote:
Originally Posted by Jonezy
I've heard some fields limiting all guns to 1.5Joules
Who? Where?


Quote:
Originally Posted by Yawger
1. EO's set a joule limit... say 2.0 joules.
2. Take the entry fee money
3. Chrono the guns before they enter the field... you can do this while you're checking for stamps and wrist bands.
4a. If player is under the 2.0 joules they get to enter the field and play.
4b. If not they don't.
The most promising method I've seen so far. Only issue I see is a player lying about bb weight during, say, an on-field spot check. Do I take some of his ammo and put it in my own gun to test if I don't trust him? Do I bring a scale with me onto the field?
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  #129  
Old 02-14-2013, 12:48 PM
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Jonezy posted a chart earlier that shows how most AEG's loose fps when you use heavy bb's.

Polar Stars do not loose as much fps as AEG's when heavy bb's are used. So when you chrono a P* at 400fps with .20 and the user switches to a .30, .33, .40 etc the joule output goes up.

If a Polar Star is shooting x bb at y fps simple math will show what the joule rating at the muzzle is. This is why most of us are reccomending chronoing for Joules using the same weight that is going to be used in the field, rather than fps.

The biggest problem with polar star's are the people who have little to no understanding of them spreading misinformation.

A P* shooting a .43 at 270 fps is going to have the same impact energy as a AEG shooting a .43 at 270 fps. Both would have 1.457 joules of muzzle energy. 1.457 is below the current .20 at 400fps limit.

What we need is a chrono chart showing bb weight's and what fps that bb can be shot at and still be under the limit.

Wether or not you trust the player to be honest about bb weight is another problem, but that could be solved by chronoing again with a random mag from their vest before entering the field.
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Quote:
Originally Posted by Texx View Post
Am pretty sure P* run off the tears of those who can't afford them.

Last edited by swervin45601; 02-14-2013 at 12:57 PM.
  #130  
Old 02-14-2013, 12:55 PM
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Okay, I have watched this thread go on for awhile. I've had conversations with many of you involved and learned some really neat things about adapting our rules and regs to fit the growth of our beloved hobby. What I have also watched is some of the most inane counter-productive banter and disrespect that I have seen on a thread for a long time.

Here is my take on the whole damn situation.

This problem is more for me a red flag problem than an equipment problem and what I mean by that is that it is reflective of a greater cultural problem that we as a community face. Are polar stars and PTW's and even ICS easier to manipulate than other airsoft guns? Yes, hell that's part of the appeal of these systems to begin with which among other reasons is why players choose to invest their money in them. When we get a new technology or a new system as EO's it is our job to see how we can integrate them into the events we run while learning all the quirks and tricks of each to maximize safety and enjoyment of all who pay their hard earned money and precious time to drive to and participate in the games that we put on.

I am not an engineer, I am not a physics expert and I mechanical talents begin and end with opening my soup with the electric can opener in my kitchen . What I DO understand very well is people and the interactive dynamics that occur between them as well as people's reactions to situations and behaviors.

Jonzey sent me a very nice PM detailing links, information and the science behind the claims, which as an EO is helpful for me to make an informed decision in how I run and maintain safety and equity at my events. For that I am thankful and I know from conversing with several other EO's on this post that the information is appreciated.

When I host (and those who have attended my events can attest to this) one of the things addressed in the safety brief is sportsmanship and respect. Consequently I can count the number of rage incidents at our events on two hands in two years. When I play and participate in my own events, I try my best to lead by example and always compliment my competition on making a good shot and you know what? When we host I hear a chorus of "hey bro, nice shot". Is that because of me? Not necessarily but it is because the tone that is set and then followed through on and encouraged by the staff and other participants.

Why that post you ask? Simple. In any discussion that comes with examining strategies to improve, evolve or enhance our games there are inevitably the people that get pissed off and feel the need to make the discussion into something it isn't. If I see a post asking a legitimate question which is how best to regulate new and or existing technology, and I feel like that is unfair, I'll start making a fuss about the mere discussion being a slippery slope to banning technology and thereby pissing in my corn flakes for the hundreds and thousands I have spent on that rig/design/setup whatever. If I shift the focus off of productive discussion and make it about something that it isn't then people get butthurt, flame wars ensue and nothing gets accomplished. Contained in this thread is a lot of good, researched scientific information but when you add insults, belitting, and generally trying to make others feel stupid for the horrifying crime of having a discussion about safety and technological implication you are setting the tone.

When I go to court and testify about a client's progress, the judge listens to me because I am an expert in my field. When someone posts great information that is relevant to the topic, I listen because it helps me understand. Now when that information is layered and interlaced with snide and insulting comments and judgements it makes it pretty hard for those who are trying to find the best solution want to tune you out. Good bad or indifferent, that's human nature guys.

If for example tomorrow I said "Out of the Box Industries will be banning polar stars from play because of reason X,Y and Z" I would have a fecal storm on my hands and rightfully so. If I say however "as an event organizer I have a responsibility to examine our chrono procedures to look at safety across the board", and I still get a fecal storm but for reasons that are only grounded in half-truths and paranoia then it makes it difficult for me to feel like I am going to get community feedback and more likely to say "to hell with it, I'm going to make a judgement call based on the best info I have."

Nobody is talking about an outright ban on Polar Stars. I am not going to kick in your door at 2 am and take your polar star because I don't have one nor am I going to tell you that you aren't welcome at my event because you have a high performance set up. I saw a blog a while ago that talked about hating playing with fat people because they are inherently lazy and won't walk back to respawn or something. Are we talking about banning fat people from playing airsoft? No, of course not.

Viper made a point I agree with. If I caught ANYONE cheating at an event in the terms we are describing i.e. a polar star swapping nozzles, regulators, whatever or a PTW doing a cylinder swap or a player who smuggled a hot gun onto the field they would be done....PERIOD. That is the point guys, we are agreeing that enforcement is a good idea but saying we can't have a discussion about anyone else because you feel unfairly singled out and deserve special dispensation that is just insane.

I love this game, I love hosting and writing complicating maddening story lines and watching people bring them to life. I love stalking someone through the creek and taking people out who didn't know a fat man could get so skinny unless it was to get some pie that was just out of reach. I love hearing people's stories about their experiences and being a part of this community. Perhaps rather than being reactionary and name calling you can let the science stand on it's own and be a part of a discussion rather than trying to discredit or make someone else feel stupid because they don't know what you do.
  #131  
Old 02-14-2013, 01:27 PM
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Jonah, I think your account got hacked by Rygar, lol.
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  #132  
Old 02-14-2013, 03:54 PM
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Polarstar: tournament locks

Quote:
Originally Posted by Darkstar View Post
Joule creep, fps creep or energy creep as it is sometime known, has been a problem with paintball guns for 20+ years. The issue has two main parts associated to the gun itself and has NOTHING to do with BB weight.

First is that as the OAT (Outside Air Temperature) increases over the course of a day, from morning to afternoon, the pressure or PSI of the gas inside a canister (CO2 in paintball, HPA, even green gas for airsoft guns) increases due to the added heat energy from the atmosphere. If you chrono a paintball gun, P*, gas blowback pistol, etc, it WILL chrono at a higher muzzle velocity in the afternoon than in the morning so long as there has been an increase in the OAT.

The second issue is one that has been around in the paintball world for literally years. I can remember the problem when I was a kid and I've never seen a regulator made that has solved this problem. Essentially what happens is that as the gun is fired, gas moves through the system and cools. Once the gas passes throuh the step-down regulator (gas regulator) and is in between the regulator and solinoid, it is trapped and is at a cooler temperature. Once this gas sits around in there, the temperature normalizes and warms up. Because of this warming effect, the PSI of the trapped gas can increase dramatically causing your next several shots to be at potentially higher muzzle velocities, resulting in more energy in the projectile. This happens to every paintball gun I've ever used, and I'd imagine the same happens in P*'s. This is generally not a major problem, though it is definitely something to be aware of. When I played tourney paintball back in the 90's, we were always required to 'clear' (dry fire) our PB guns just prior to stepping on the field as some teams would 'prep' their guns so that they would have an unfair advantage.

The problem isn't really something that is easily fixable with regard to P* guns. It is something that EO's AND P* owners need to be aware of at all times. There is no doubt that P* owners will be under greater scrutiny because of the physics and effects that occur when using P* rifles, but it doesn't need to be a bad thing, however it can be an inconvenience to P* owners. Please realize that these inconveniences are not done to single you out, ban you or make your playing experience a more expensive one. It's done simply for the safety and fun of all players, and I've heard my share of complaints about P* guns already, so it's definitely an issue and this is why we're discussing it.
Cool. It's already been shown to not be a significant problem because of the way the gas is regulated twice to three times after it escapes the tank. You're not going to see any sort of measurable difference throughout the day or at least one that would be cause for concern. That "dramatic" increase in PSI in the line is only when liquid gases like propane and CO2 escape into the line, boil, and exert more pressure on the line. It's why you see so many remote line setups (which, by the way, is what PolarStar users use) so that the gas could have a better chance to heat and boil. Air is much different and much more stable than any gas that is stored as a liquid and boils at SATP. You also can't accurately apply cool down effects from paintball HPA setups because they move WAY more air than PolarStar engines do. It takes a massive volume of air and amount of work to displace a paintball than it does to displace a BB. Paintball guns guzzle gas and chill the tank and lines far more than PolarStars do because of this and if a PolarStar user ever were to cause their air system to cool as much as a paintball gun would in-game and create the problem you're talking about, in a multiple step-down regulated HPA system, they ought not to be allowed to play because they're sending BBs downrange like they're free for minute-long bursts or more and potentially doing serious harm to their opponent.

Quote:
If anything, your suggestion seems to give you the advantage over other players, though you are actually putting yourself at a disadvantage. Let me explain.
You have this backwards. Look at the last table I posted and look at the numbers. A lower muzzle energy is a disadvantage, end of story.

Quote:
AO's chrono rules were developed about 10 years ago by a group of EO's and players, and I believe Blade was part of that group too. I had a lot of input myself, as well as many others. After discussing the matter for several months and people doing lots of reduntant testing, the .20g@400fps general limit was established and this discussion now is precisely why the 400fps w/.20g BB velocity limit was set in the first place. The 400fps limit was actually designed to account for the joule ratio of heavier BB's up to .50g to be within certain Joule limits. It was why anything over 400fps had to be semi-auto only. The testing was done both with and without hopup, and the type/diameter of barrel used was irrelevent. All we were concerned about was meausuring the raw velocity of .20g BB's exiting the barrel and calculating the energy at the muzzle. An AEG shooting a .20g BB at 400fps is going to have exactly the same muzzle energy as a P* shooting a .20g BB at 400fps. If you plop heavier BB's in those guns, yes, the Joules increase, but this was accounted for in the original system. 400fps w/.20's was the established maximum so that everyone was on the same level. If someone wants to shoot .40's in their AEG, there is NO limitation to them doings so (unless the field has banned heavy BB's).
Which is all the more reason why people need to stop and actually think for a moment about why this standard was set. It's because of the muzzle energy of the projectile, not just the FPS. PolarStars and other HPA platforms present a unique problem because of how they respond to different weights of BBs. Don't allow yourself to fall into the pattern of applying knowledge and experience with AEGs to PolarStars because it's a completely different animal. In this respect, it's apples to oranges, guys.

Quote:
Using the 400fps method, NO ONE is as a disadvantage. Everyone is on a level playing field because they were all tested to the SAME standard. See where this is going?? This entire argument is completely ridiculous as it doesn't matter what BB weight you use, P*'s are going to have Joule creep either way, and that's what the real issue is and it's not one that is easily solved without having several step-down regulators, and even that doesn't completely solve the problem.
Except the unlucky kid that gets shot at 2J from 100' because the shooter or the EO doesn't know his gun is putting out that kind of power. Again, we're already using multiple step-down regulators by default.

Quote:
Tried this in the past. It is just too time consuming for everyone to test with different weights. There are too many variables, and too many dishonest players (sorry, but it's true). Iv'e had people try to sneak hot guns past me by saying they had .20's when they were really shooting .30's. Having the EO at the chrono station with their own .20's for testing has been the most effective method I've used, and it tests EVERYONE to the same standard and gives no one an advantage or disadvantage. Keep it simple. You just seem to be overcomplicating things.
Test with 0.20g BBs first, then test with the player's BBs. If the FPS doesn't drop much or registers 390 FPS with the 0.20g BBs, you may have a problem. That's not overcomplicated.

Quote:
It sure does!!! As I started out on this post above, this has been a very well known issue in paintball guns for years. 20+ years. The same thing happens to gas blowback pistols and rifles, and especially CO2 pistols. HPA does the same thing. Just looking at a PSI chart for Propane, it's pressure increases approximately 20PSI for every 10 degrees F. So there can be a huge difference between a gun chronoing legally in the morning when it is 60 degrees outside to the afternoon when it is 85F. CO2 and HPS have even greater pressure differentials due to the fact that they are a MUCH higher pressures.
Again, you can't compare a paintball air system to a PolarStar air system. Paintball guns consume air from the tank faster than PolarStars do and cause this problem. If someone with a PolarStar were to push their gun to the point where gas expanding in the lines after the multiple step-down regulators is becoming a problem, they shouldn't be allowed to play in the first place. Sorry, but it just doesn't apply to any measurable extent here.

Quote:
The .20@400 limit originally took heavy BB weights into consideration, so that is why I'm wondering why people are going to far to overcomplicate the topic.
Because we now have a resurgence of platforms that throws all the considerations about using heavier BBs in AEGs out the window. The PolarStar system doesn't maintain its energy output as it should and as an AEG does. Look back at the examples and see for yourself or better yet, get some experience with the system and come back with an educated response.

Quote:
Originally Posted by Sky View Post
I've seen you chart 24 shots with your polar star. Enough for you to prove a point here in internet land, not enough for us to use this as a safety standard for events across the state. Let's do more of this and perhaps create your own Airsoft Trajectory Project for Polarstars. Let's get that bad boy pier-reviewed - not the worst use of time for an aspiring engineer.
I never claimed to have come up with any kind of a safety standard for events across the state. I merely made a point with a table because there are people on this forum that don't understand what happens in the REVERSE situation of what I suspect we've been having on the field - that chronographing and restricting players with PolarStars based on the worst case scenario severely infringes on their ability to compete with everyone else. You don't have to get all mad at me over it. There's no shame in not knowing something but there is in being willfully ignorant to facts being presented to you on a silver platter from every direction.

Quote:
Who? Where?
I didn't post that. Darkstar did. Take it up with him.

Quote:
Only issue I see is a player lying about bb weight during, say, an on-field spot check. Do I take some of his ammo and put it in my own gun to test if I don't trust him? Do I bring a scale with me onto the field?
Ah, this is the real trick, isn't it? You can never be sure without weighing a sample of the player's BBs, so using a small portable scale would be an option, but which BBs do you weigh? The ones from a mag randomly selected from the player's vest? The one in their gun at the time you walk up? What if they have different weights of BBs in some of the mags? What if all the mags they're visibly carrying are decoys loaded with 0.25g BBs and the real mags they're using are concealed in all manner of places on their person? Again, it falls back onto having to trust the player somewhere along the line.

If they chrono at, say, 399.999 FPS with a 0.20g and are using a PolarStar at an event where the limit is 1.5J, you have yourself a case of probable cause for weighing BBs since anything over a 0.20g will lead to likely being over the limit of 1.5J. The knowledgable player that has taken joule creep into consideration with their PolarStar will chrono somewhere around 360-380 FPS with a 0.20g BB because their heavier BBs will cause their muzzle energy to be higher.

Quote:
Originally Posted by swervin45601 View Post
I think this would help a lot. Heres a link to a joule chart. (center top row)
This one?



Yes, that would help a lot. Good find


Quote:
Originally Posted by OverLord View Post
While im not trying to argue with either of you and am more or less raising a question, If this is the case, why then will gas guns not work in cold weather? If your theory holds true, the pressure of a mag of gas in the cold and warm air should have no difference (Again, it could be another factor, please enlighten me if so)

In my personal experience, shooting any gas weapon in cold weather is generally a flop. After warming the mag in your pocket for a few seconds, you get a noticeable performance increase. From what i have been led to believe, the whole gas guns and cold weather concept stems from atmospheric pressure rather than gas temperature.

Again someone please explain to me why this effect happens and why P* are able to run cold weather better and not be subjected to temperature and pressure issues while other gas guns are horrendously effected.
Good question! I'm going to assume you mean green gas/propane and CO2 when you refer to "gas guns". It has to with how the gases are stored as liquids under pressure. When you compress CO2 or propane enough, they change from a gas to a liquid and your gun uses the gas that boils from that liquid. It sits atop the denser liquid in the magazine which is why when you turn your GBB pistol upside-down, frost forms on the parts and gas spews from the chamber and barrel. This is also why you're supposed to hold the magazine upside-down when you fill it with gas. As you cool the liquefied gas down when you take it outside on a cold winter day, it slows the boiling process and produces less gas for the gun to use. You can see the same effect for yourself when you take a vigorously boiling pot of water on the stove and slowly decrease the temperature to where it's still boiling but just barely. That same process happens inside your gas mags in the cold.

HPA doesn't have this problem because it doesn't liquefy under the pressures we store it at. It's just a super compressed gas that stays a gas and it tends to not cool down as much as CO2 and propane as it expands and is used by the gun; no boiling process to fight with in the cold.

Safety is always of the utmost importance in this hobby, followed by having fun. Without safety, this hobby wouldn't even exist to the extent it does today, yet without enjoyability, it also wouldn't exist. The tightrope between the two that binds them is a narrow one and in the end, people like Jonah and Blade are going to have to find a way to walk it without eroding one group's ability to have fun or compromising the safety of all.

Last edited by Jonezy; 02-14-2013 at 07:47 PM.
  #133  
Old 02-14-2013, 04:38 PM
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@Jonezy. Okay, that makes a bit more sense. If the P*'s have a 3 or 4 step, step-down system, then it would reduce the possibility of liquids boiling, like you said, but could still allow for some gas expansion. As you said, it takes a lot more gas to propel a paintball than an airsoft BB, and any pressure deviation would be a lot more noticable with an airsoft BB. I'd love to do some velocity tests on a P* over the course of a normal day. Maybe when things warm up.

Now I'm not really sure why you have the impression that a P*'s BB is going to behave differently. Maybe P*'s were built by Apple and contain some magic that I'm unaware of, but a .20g BB traveling at 400fps is going to have the same amount of impact energy regardless of how it got up to that speed. If we use an AEG, gas gun, P*, or if we threw it with our bare hands, a .20g BB travelling at 400fps is always going to have the same energy.

Look at it this way. If you set up a chrono station about 3 feet in front of your muzzle break, and you have an AEG, gas gun and P* all tuned to shoot exactly 400fps with .20's, then they are all outputting the same amount of muzzle energy. The gun no longer has any effect on the BB, and so long as the hopup is set exactly the same on each of the three guns, the BB's should all travel in a very predictable flight path with the same range.

What I seem to gather from what you are saying is that just by using a Polar Star rifle, using heavier BB's is going to result in a higher Joule energy curve compared to an AEG or other airsoft gun. Is that right?

Now do keep in mind that yes, when you tune any gun, AEG or otherwise, to 400fps with .20g BB's and then swap your BB's out with heavier BB's, those BB's WILL carry more energy because they have more mass. This would only be a problem with events that would restrict muzzle velocities to a Joule limit (like the 1.5J you referred to already). Otherwise, with events that do not have Joule restrictions and use current AO restrictions, those energy deviations have already taken that into account.

Maybe I'm misunderstanding the problem, but I can't really see how P*'s are all that differrent from other guns with respect to standard muzzle energies. Like I said, the only thing I'm aware of "creep" wise is what I've explained before in relation to pressure changes as temperature increases.
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  #134  
Old 02-14-2013, 05:26 PM
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Originally Posted by Darkstar View Post
Maybe I'm misunderstanding the problem, but I can't really see how P*'s are all that differrent from other guns with respect to standard muzzle energies. Like I said, the only thing I'm aware of "creep" wise is what I've explained before in relation to pressure changes as temperature increases.
With a p* system we are able to tune how long the system blows air out the barrel, So with a .2 it is in the barrel for X amount of time say 20ms(milliseconds) when you go to a bigger bb it takes more energy to get it moving so it stays in the barrel for say 50ms. With a p* I can make the gun propel the bb for as long as it is in the barrel, so in this situation I would change my DP so that it blows air out the barrel for 51ms so the bb is always accelerating and gaining more energy. in an AEG you have a set amount of air that will comeout EVERY time it isnt going to change when you switch bbs that is why you see a bigger drop off, it reaches a point where it is no longer accelerating faster.
This is why a p* is a DMR dream, you can 100% volume match the barrel in ways that have never been possible in the past.


You can replicate these same joule creep results by taking a CQB m4 and throwing a full (#0) cylinder in it, it will push out more air resulting in the same style of creep as a p*.
^this is why discussing joule creep for just p*s is a lost cause. Anyone can replicate the same results with an AEG
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Old 02-14-2013, 05:26 PM
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Polarstar: tournament locks

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Originally Posted by Darkstar View Post
@Jonezy. Okay, that makes a bit more sense. If the P*'s have a 3 or 4 step, step-down system, then it would reduce the possibility of liquids boiling, like you said, but could still allow for some gas expansion. As you said, it takes a lot more gas to propel a paintball than an airsoft BB, and any pressure deviation would be a lot more noticable with an airsoft BB. I'd love to do some velocity tests on a P* over the course of a normal day. Maybe when things warm up.

Now I'm not really sure why you have the impression that a P*'s BB is going to behave differently. Maybe P*'s were built by Apple and contain some magic that I'm unaware of, but a .20g BB traveling at 400fps is going to have the same amount of impact energy regardless of how it got up to that speed. If we use an AEG, gas gun, P*, or if we threw it with our bare hands, a .20g BB travelling at 400fps is always going to have the same energy.

Look at it this way. If you set up a chrono station about 3 feet in front of your muzzle break, and you have an AEG, gas gun and P* all tuned to shoot exactly 400fps with .20's, then they are all outputting the same amount of muzzle energy. The gun no longer has any effect on the BB, and so long as the hopup is set exactly the same on each of the three guns, the BB's should all travel in a very predictable flight path with the same range.

What I seem to gather from what you are saying is that just by using a Polar Star rifle, using heavier BB's is going to result in a higher Joule energy curve compared to an AEG or other airsoft gun. Is that right?

Now do keep in mind that yes, when you tune any gun, AEG or otherwise, to 400fps with .20g BB's and then swap your BB's out with heavier BB's, those BB's WILL carry more energy because they have more mass. This would only be a problem with events that would restrict muzzle velocities to a Joule limit (like the 1.5J you referred to already). Otherwise, with events that do not have Joule restrictions and use current AO restrictions, those energy deviations have already taken that into account.

Maybe I'm misunderstanding the problem, but I can't really see how P*'s are all that differrent from other guns with respect to standard muzzle energies. Like I said, the only thing I'm aware of "creep" wise is what I've explained before in relation to pressure changes as temperature increases.
Have you been paying attention at all? Look what can happen when you chrono someone with a PolarStar with 0.20g BBs to be under the limit and they go to use a 0.43g in game:



If you can't see the difference in the shaded cells at the bottom, you're hopeless. POLARSTAR GUNS DO NOT MAINTAIN A CONSTANT MUZZLE ENERGY AS YOU INCREASE THE MASS OF THE BBS YOU USE IN THEM. They can DRAMATICALLY increase the muzzle energy as you step up the BB weight without any adjustment from the user and this is why people have been complaining about unusually hard hits.

Furthermore, they can only be powered with high pressure air. High pressure air does not undergo a phase change at the pressures we put it under. There is no changing from a liquid to a gas in the tank in an HPA setup. Do you understand this yet?

Last edited by Jonezy; 02-14-2013 at 05:28 PM.
  #136  
Old 02-14-2013, 05:42 PM
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^calm down buddie lol
I hope my explanation makes it alittle better, Idt if seen it broken down like that yet here... Also Jonezy I think we have work to do................ Ill pm you to discuss it further.
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Old 02-14-2013, 05:51 PM
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I'm calm, I'm just running out of options for making simple things clearer to him. Awaiting PM.

*edit* Take a look at these two threads, everyone: http://www.pstartalk.com/showthread....with-P*-vs-AEG and http://www.pstartalk.com/showthread....9-Energy-Creep

There's a wee bit more data for you, Sky. You can find the rest on your own because every setup will show different results. I'd venture as far as to say that the majority of stock AEGs don't suffer from this sort of joule creep. This is probably what Darkstar is referring to when he talked about the testing that was done 10 years ago because if you took an off-the-shelf AEG, chronoed it to be at 1.5J with a 0.20g, and then chronoed it again with a 0.40g, the muzzle energy would be the same.

When you take that stock AEG and start playing with different variables by changing and modifying some very specific parts, you can get it to have the same kind of joule creep that a PolarStar is capable of. I could get a stock gun to jump from 1.5J with a 0.20g to 2.5J with a 0.43g with $40 worth of parts and under an hour's worth of time. You can even get one to increase its muzzle energy when you adjust the hopup to where you'll use it for the day. The point is that we never used to have problems with joule creep on this kind of scale because it was so rare and there wasn't a prime target to blame it on like the PolarStar has become. Now we've got more and more people playing with PolarStar guns and GBBRs and they can easily replicate the joule creep phenomenon you used to only see once in a blue moon. AEG cylinders have a fixed volume of air usually matched to the barrel volume (or at least vaguely close). We change our FPS levels by swapping springs and that only changes the pressure reached behind the BB as it is fired. You can't change the volume without swapping cylinders or barrels and overvoluming the system. In the PolarStar platform, you can change both the pressure and the volume to perfectly match your specific barrel. The average Joe can even configure a PolarStar to shoot at 1.5J or more with a longer upper and heavier BBs and then down to CQB levels with a shorter upper and lighter BBs without making any adjustments to the regulator or board settings.

When a PolarStar user takes the time to adjust their dP setting, or poppet dwell, they are adjusting how much air is released into the barrel. They can tune this down to the number of milliseconds the poppet dwell is open and expelling air into the barrel. If you do this adjustment correctly, you end up tuning the system to where it expels air into the barrel just long enough for your BB of choice to reach the muzzle and then the valve closes. This causes the BB to be rapidly accelerated throughout the entire length of the barrel. When you load a lighter BB into the gun, it takes less work to propel it through the barrel and out the muzzle, leaving an excess of air that escapes after the BB that is essentially unused. That lighter BB doesn't absorb energy from that extra air and therefore, it carries a lower kinetic energy than the BBs you tuned the system for and that leads to inaccuracy at the chrono booth. All you'd see is a partial amount, joules or FPS, of what the system can actually do as far as energy output. You can see this in the table I put up as well as the ones contained in the above links.

Regular gas guns have the capability to do this, too. I'm not talking about gas pressures in mags increasing with the temperature or any of that simple stuff almost everyone knows but rather about how they expel gas down the barrel until the BB exits regardless of BB mass. I don't have a gas gun handy to show this but basically the same thing happens as what you can see in a PolarStar and a properly configured AEG. With the increasing prevalence of gas guns of all types on the field, you are going to see more instances of massive joule creep and I'd wager that in the vast majority of cases, the users have no idea it's even happening. The ONLY way to fully address this and effectively prevent it from happening is to chronograph all guns exactly as they will be used for the day. Of course, this would cause things to take a hell of a lot longer at the chrono station so you could just chrono all gas gun users like this and continue using the old system with AEGs, which as far as I can tell, still hold the majority at most fields in Ohio. Chronoing gas guns with the heaviest BBs you can find and forcing everyone to be under a certain muzzle energy limit (like Sky wants to do) will completely screw them over when they go to use lighter BBs because their muzzle energy will drop so much that they'll basically have ~1.2J CQB guns but the EOs and referees will think they have the same energy output as a field gun and treat them as such. Congratulations, you've just slapped an MED on a ~1.2J gun and handicapped all but AEG users to CQB power levels.

Let's turn the clock back a few months when the ROF storm was raging here. In the midst of everything, Fallen Warriors decided to limit BB mass to 0.25g for all full-auto guns at their Hard Core games for some reason. A fecal storm hit, they changed their minds, and decided to chrono based on muzzle energy. No matter what, if you have a gun that consistently puts out the same amount of energy regardless of what mass of BB you run through it (like my stock CYMA, for example), heavier BBs will retain more energy on their way to the target. It will give the illusion that someone is being shot from closer than they actually are, but this difference in energy between 0.20g BBs and 0.40g BBs is not enough to matter much in the grand scheme of things. Joule creep from guns that exhibit it and cheap Chinese green laser pointers are a much greater safety hazard than the difference in energy between 0.20g BBs and 0.40g BBs imparted on a person, in my honest opinion. This is why I have refused to attend OP: Blackgate - because a decision based on a "play test" was made to ban BBs heavier than 0.28g for reasons not even remotely based on facts that are easily, EASILY accessed by anyone with Internet access. Would >0.28g BBs hurt someone more than <0.28g BBs fired with the same muzzle energy? Possibly, but it's not going to break skin at ~1.2J and it's certainly not going make it any less fun for someone getting shot with a 0.30g BB or even a 0.40g vs. a 0.28g BB. For all we know, Sky's "play test" was done with a gun that had massive joule creep and exacerbated the effects of the "heavy sniper BBs."

Last edited by Jonezy; 02-15-2013 at 11:58 AM.
  #138  
Old 02-14-2013, 10:00 PM
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Good question! I'm going to assume you mean green gas/propane and CO2 when you refer to "gas guns". It has to with how the gases are stored as liquids under pressure. When you compress CO2 or propane enough, they change from a gas to a liquid and your gun uses the gas that boils from that liquid. It sits atop the denser liquid in the magazine which is why when you turn your GBB pistol upside-down, frost forms on the parts and gas spews from the chamber and barrel. This is also why you're supposed to hold the magazine upside-down when you fill it with gas. As you cool the liquefied gas down when you take it outside on a cold winter day, it slows the boiling process and produces less gas for the gun to use. You can see the same effect for yourself when you take a vigorously boiling pot of water on the stove and slowly decrease the temperature to where it's still boiling but just barely. That same process happens inside your gas mags in the cold.

HPA doesn't have this problem because it doesn't liquefy under the pressures we store it at. It's just a super compressed gas that stays a gas and it tends to not cool down as much as CO2 and propane as it expands and is used by the gun; no boiling process to fight with in the cold.

Safety is always of the utmost importance in this hobby, followed by having fun. Without safety, this hobby wouldn't even exist to the extent it does today, yet without enjoyability, it also wouldn't exist. The tightrope between the two that binds them is a narrow one and in the end, people like Jonah and Blade are going to have to find a way to walk it without eroding one group's ability to have fun or compromising the safety of all.
Thanks for the explanation, that makes so much more sense now.

Carry on gents.
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Old 02-15-2013, 02:03 PM
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Originally Posted by Jonezy View Post
If you can't see the difference in the shaded cells at the bottom, you're hopeless. POLARSTAR GUNS DO NOT MAINTAIN A CONSTANT MUZZLE ENERGY AS YOU INCREASE THE MASS OF THE BBS YOU USE IN THEM. They can DRAMATICALLY increase the muzzle energy as you step up the BB weight without any adjustment from the user and this is why people have been complaining about unusually hard hits.

Furthermore, they can only be powered with high pressure air. High pressure air does not undergo a phase change at the pressures we put it under. There is no changing from a liquid to a gas in the tank in an HPA setup. Do you understand this yet?
For the love of God, Jonezy, calm down!!!

Yes, I know EXACTLY what you're talking about. I UNDERSTAND that HPA doesn't go through the boiling state!! But it STILL doesn't make any sense that if you set up your P* to shoot ~400fps with .20's that it would defy the laws of physics and suddenly, in some unexplainable way, add additional energy to a .43 gram BB. If that is what is really happening, then I don't have an explanation of why it occurs, though it obvious is a major concern for EO's. If this is truly happening, then obviously chronoing with the BB's you plan to use on the field makes sense. I just can't explain why this pressure issue is occuring.

Has P* said anything that might shed light on why this is happening?

I also just tested an M4 that is tuned to about 399fps with .20's, and it was shooting at about 335fps with .30's. Even that would output 1.58 (technically illegal at fields with 1.5J limits). But like I said, if your gun is truly shooting 400fps with .20's and then 330 with .43's without ANY adjustments at all, then I can't offer an explanation on what is happening. I wish I could see it and run my own tests to validate. Not that I don't believe you, but I like to run my own tests to validate the results of others.
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  #140  
Old 02-15-2013, 03:08 PM
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Originally Posted by Darkstar View Post
For the love of God, Jonezy, calm down!!!

Yes, I know EXACTLY what you're talking about. I UNDERSTAND that HPA doesn't go through the boiling state!! But it STILL doesn't make any sense that if you set up your P* to shoot ~400fps with .20's that it would defy the laws of physics and suddenly, in some unexplainable way, add additional energy to a .43 gram BB. If that is what is really happening, then I don't have an explanation of why it occurs, though it obvious is a major concern for EO's. If this is truly happening, then obviously chronoing with the BB's you plan to use on the field makes sense. I just can't explain why this pressure issue is occuring.

Has P* said anything that might shed light on why this is happening?

I also just tested an M4 that is tuned to about 399fps with .20's, and it was shooting at about 335fps with .30's. Even that would output 1.58 (technically illegal at fields with 1.5J limits). But like I said, if your gun is truly shooting 400fps with .20's and then 330 with .43's without ANY adjustments at all, then I can't offer an explanation on what is happening. I wish I could see it and run my own tests to validate. Not that I don't believe you, but I like to run my own tests to validate the results of others.
I'm calm. I understand that things don't seem to add up, but they do. A question for you or whomever can answer it as I was not around 10 years ago: Did you get the 0.5 to 1J increases in muzzle energy with high-mass ammo during those tests that determined the 400 FPS w/0.20g standard we use today or were the increases far more subtle than that?

Joule creep doesn't defy the laws of physics, it just makes clever use of them. I explained this a tad better in my last post but it comes down to air volume expelled by the system and how heavier BBs remain in the barrel longer, thus absorbing more energy than lighter BBs, and leading to a higher muzzle velocity and muzzle energy than it *should* have on paper.

When you take a gun like what you used to get your results you just posted and run various masses of BBs through it, you get the results you do because the volume of the cylinder was set such that it would propel a ~0.20g BB for the duration of its time in the barrel and little to no extra. Little to no extra unused air escapes behind the BB in that gun you tested. When you run a heavier BB in it, that heavier BB takes more time to accelerate and absorbs all the energy it possibly can from the cylinder before it reaches the muzzle. The piston hits the cylinder head before the BB exits the barrel and the BB coasts for the rest of its time in the barrel, burning off some of its kinetic energy from air resistance, friction against the ceiling of the barrel, and from gravity. This is why it exits the barrel at around the same energy as a 0.20g BB does.

Now if you were to take that same gun you got those results with, open it up, install a type 0 cylinder or a type 0 bore-up cylinder, possibly use a shorter barrel, and repeat the test, you'd get very different results. The 0.20g BB would still measure out to be around 1.5J but the more you increase the mass of the BB, the higher the muzzle energy will climb. Since you now have a surplus of air volume from the cylinder, you can continue to accelerate that high-mass BB for the duration of its time in the barrel. Instead of the piston head impacting the cylinder head before that high-mass BB exits the barrel, it takes a few milliseconds longer and the BB has a better chance to exit the barrel before the system bottoms out and stops imparting energy on the BB.

EPIC ANALOGY TIME - I finally found a better way to explain this stuff.

Picture a drag race track where two cars are set up to race each other but the winner is determined by which has the greater kinetic energy of the two when they cross the finish line. One of the cars is stripped-down and lightweight whereas the other is heavier, but they both have the same engine. The lighter car will reach the end of the track first and have, say, 100J of kinetic energy when it reaches the finish line, but it has not reached its top speed. It gets there the fastest (assuming it cannot reach a higher speed in the distance it is given to finish the race) while the other car takes longer to get up to speed. However, 3/4ths of the way down the track, the heavier car cuts out its engine and coasts through the same finish line the lighter car does. Both cars finish with roughly the same kinetic energy.

The cars are reset to the starting line and the finish line remains where it was during the last race. The race is repeated, although this time, the driver of the heavier car keeps his foot on the gas pedal the whole time and doesn't coast to a stop like he did before. He blows past the finish line at a slower speed than the lighter car did (remember, the lighter car cannot reach its top speed in the distance it's given to finish) but because of the mass of his car, he wins the race because he has the most kinetic energy as he crosses the finish line. The lighter car had 100J of kinetic energy as it crossed the finish line but the heavier car had 130J. Take a guess at what happens when you move the finish line for just the heavier car further and further from the starting line, still assuming that the lighter car cannot reach its top speed before it crosses its own finish line AND assuming that even with the excess mass, the heavier car can still reach the same top speed as the lighter car, although it would take a longer track to do that.

The same thing happens when you have an overvolumed air system. Instead of the heavier BB coasting for part of its time in the barrel, it is constantly propelled for the duration of its time in the barrel and reaches a higher velocity than it *should*. If you'd like to replicate this, take any AEG that comes stock with a type 3 cylinder and chronograph it. You should get the same results as you just did with your last test and the tests you or whoever ran 10 years ago. Then take the type 3 cylinder out of it and replace it with a type 0 or a full bore-up cylinder with NO ports. You'll then start to see the joule creep phenomenon come into play.

The same thing is happening with PolarStar guns and some gas guns out on the field. They continue to propel the BB, regardless of mass, down the entire length of the barrel and leading to this fun little problem leaving so many scratching their heads at. What used to be a dark art among a handful of techs some 5-10 years ago, the ability to propel heavy BBs throughout the duration of their travel through the barrel, is now available for the masses for the low, low price of $500 + $100 tanks and a $175 air rig. You've also got people like this:



...with step-by-step guides that show how to adjust the volume of air moved by the system in PolarStar guns and it can lead to the massive joule creep that is causing players to complain about unusually hard hits IF you don't adjust your regulator for your own ammo. That captured post is a recipe for sidestepping the underlying rules regarding muzzle energy unless you actually figure out what FPS your own BBs should be under to be within the limits and not just go off of what velocity a chrono reads with a 0.20g BB, which is likely what people have been doing and not even knowing the consequences.

I apologize for losing patience with you in that post of mine you quoted. This was difficult for me to figure out back when I first learned about this phenomenon so I can understand why it is for you or anyone else for that matter. The solution is still to chrono based on how the gun will be fielded, as in having its hopup set to where you'll be using and with the BBs you'll be using for the day.

Last edited by Jonezy; 02-15-2013 at 06:26 PM.
  #141  
Old 02-15-2013, 03:22 PM
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What is Poppet Dwell? Seems like it is either something to do with the hopup, or possibly something to do with the air system?
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  #142  
Old 02-15-2013, 03:29 PM
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What is Poppet Dwell? Seems like it is either something to do with the hopup, or possibly something to do with the air system?
Poppet dwell refers to how long the poppet valve is open and dumping air down the barrel. It adjusts the volume of air you throw down the barrel. It's equivalent to changing the type of cylinder you install in an AEG.
  #143  
Old 02-15-2013, 03:42 PM
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EPIC ANALOGY TIME - I finally found a better way to explain this stuff.

Picture a drag race track where two cars are set up to race each other but the winner is determined by which has the greater kinetic energy of the two when they cross the finish line. One of the cars is stripped-down and lightweight whereas the other is heavier, but they both have the same engine. The lighter car will reach the end of the track first and have, say, 100J of kinetic energy when it reaches the finish line, but it has not reached its top speed. It gets there the fastest (assuming it cannot reach a higher speed in the distance it is given to finish the race) while the other car takes longer to get up to speed. However, 3/4ths of the way down the track, the heavier car cuts out its engine and coasts through the same finish line the lighter car does. Both cars finish with roughly the same kinetic energy.

The cars are reset to the starting line and the finish line remains where it was during the last race. The race is repeated, although this time, the driver of the heavier car keeps his foot on the gas pedal the whole time and doesn't coast to a stop like he did before. He blows past the finish line at a slower speed than the lighter car did (remember, the lighter car cannot reach its top speed in the distance it's given to finish) but because of the mass of his car, he wins the race because he has the most kinetic energy as he crosses the finish line. The lighter car had 100J of kinetic energy as it crossed the finish line but the heavier car had 130J. Take a guess at what happens when you move the finish line for just the heavier car further and further from the starting line, still assuming that the lighter car cannot reach its top speed before it crosses its own finish line AND assuming that even with the excess mass, the heavier car can still reach the same top speed as the lighter car, although it would take a longer track to do that.
I do understand what the Joule Creep is, BUT I have a question for you that may seem to follow this post, and Dark's question.

Could the possible reason for Joule Creep have to do with the fact the AEG cylinder and piston only use a SET amount of air-volume, while P* doesn't? With only the heavier tensioned spring negotiating the velocity of the amount air exiting the nozzle, there will always be the same amount of "air-space" behind your BB.

With the P*, there is technically no amount of "air space" behind the BB, therefore the nozzles (which I could compare to the springs) and set amount of exit pressure(another comparison for springs) in the lines are the negotiators of the power behind the BB...leading to your kinetic energy car theory.
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  #144  
Old 02-15-2013, 03:44 PM
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Ohhh okay, I see then. So there's not a fixed ratio of air blowing down the barrel. Hmm. I see what is happening now.

So yea, that is a major headache and I see why Blade is so concerned about the problem. So I see your point. Yes, you'd need to chrono for energy/BB weight and not muzzle velocity at the chrono station.

I guess the only other thing you could do to counteract the problem would be to reduce the poppet valve timing to the point where it would essentially spill out the same/similar volume of air that an AEG would put out. But like the post you referenced above, each gun would need to be individually tuned for that kind of performance. It's easier to just keep the valve open for the maximum or minimum times, but neither setting would give you optimum performance.

Okay, so now that we're on the same page, continue with the ban discussions, lol!

Thanks for bearing with me Jonezy. I'm not familiar with P*'s and didn't even know they could be adjusted in such a way. And now I understand how people are shooting BB's 300 feet! lol

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Originally Posted by Flenner View Post
I do fully understand what the Joule Creep is, BUT I have a question for you that may seem to follow this post, and Dark's question.

Could the possible reason for Joule Creep have to do with the fact the AEG cylinder and piston only use a SET amount of air-volume? With only the heavier tensioned spring negotiating the velocity of the amount air exiting the nozzle, there will always be the same amount of "air-space" behind your BB.

With the P*, there is technically no amount of "air space" behind the BB, therefore the nozzles (which I could compare to the springs) and set amount of exit pressure(another comparison for springs) in the lines are the negotiators of the power behind the BB...leading to your kinetic energy car theory.
Yep, that's exactly what they're doing. By adusting the poppet dwell time, you can increase or decrease the amount of air volume entering the barrel, thus accelerating the BB for a longer period of time.
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  #145  
Old 02-15-2013, 04:00 PM
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Just wanted to pop in and say Thanks guys! I have learned, and still learning a LOT about the workings of the P*. With some of the stuff posted here, I have a much better understanding on the mechanics behind the system, and why it's cutting edge. I can see why folks drop the massive amounts of money into a P*. It's still not for me, but I can sympathize with the feeling of the P* owners about heavy restrictions. On the other hand, I can also see where the EO's are at for safety. this will be a difficult topic and perceived problem to resolve, but I'm sure that it will get there eventually. Just remember, a successful compromise is one where both parties are equally unhappy.
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  #146  
Old 02-15-2013, 04:17 PM
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Rygar, yep, I'm with you for the most part, but it's still a tough call for EO's. Two problems exist. One is really unintentional, in that the P*'s have an inherent issue regarding the way BB's behave relative to the amount of air volume entering the gun's barrel during firing. The second is the same intentional issue that PTW and ICS owners are scrutinized over, which is the ability to swap cylinders for different muzzle velocities. Personally I have a zero tolerance for the latter, though I've never caught anyone doing it. I would hope P* owners would be just as trustworthy, but the potential for exploitation can still exist. That possibility creates liability, and that's really what the EO's are worried about. They're not worried about the honorable player. They're worried about the a$$hats that cause problems, cheat, etc. But it's good that we're having this conversation.

Really this isn't an issue of Joule creep at all. It's just how the guns perform since they let a greater volume of air into the barrel. That's why I was originally confused, because creep usually refers to the boiling effect of CO2 or green gas as temperatures increase of the course of a day. Since now I know how the P*'s operate, it's a completely different problem/issue altogether.

Glad we're all learning something here!
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  #147  
Old 02-15-2013, 05:10 PM
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Quote:
Originally Posted by Flenner View Post
I do understand what the Joule Creep is, BUT I have a question for you that may seem to follow this post, and Dark's question.

Could the possible reason for Joule Creep have to do with the fact the AEG cylinder and piston only use a SET amount of air-volume, while P* doesn't? With only the heavier tensioned spring negotiating the velocity of the amount air exiting the nozzle, there will always be the same amount of "air-space" behind your BB.

With the P*, there is technically no amount of "air space" behind the BB, therefore the nozzles (which I could compare to the springs) and set amount of exit pressure(another comparison for springs) in the lines are the negotiators of the power behind the BB...leading to your kinetic energy car theory.
Yes, exactly. In an AEG, you have a relatively fixed volume to play with because in order to change the volume of air the system moves, you have to change the cylinder. Aside from porting your own cylinder, which you can do with a drill press and the proper deburring tools, AEGs don't offer anywhere near the amount of flexibility as a PolarStar does with regards to volume adjustment. You'll notice that I never clear 500mm in barrel length in any of my AEGs for a reason.

When you swap a spring out in an AEG, you are changing the pressure at which that fixed volume of air reaches in the cylinder and barrel assembly. This is why we have things like air seal nozzles and hard buckings because at higher pressures, air will leak out more rapidly. The nozzle to bucking interface, the bucking to barrel interface, and the and the nozzle to cylinder head interface are where air tends to escape the most, which is why the first thing to do when you're building a DMR is to eliminate all sources of leakage to get the energy output you're seeking.

In a PolarStar, we adjust the pressure behind the BB in two ways: the output pressure of the regulator and the rate at which air may be expelled from the nozzle and into the barrel via adjustment on the regulator itself and the swapping of nozzles. As you step down from the highest-rated nozzle, you gradually restrict the space the air has to travel through to get into the barrel, leading to the different FPS ranges each nozzle is color-coded for. The back pressure generated by the lower-rated nozzles is unfavorable for air conservation, which is why you see so many people use the red nozzle all the time and simply cut the output pressure on the regulator back.

Quote:
Originally Posted by Darkstar View Post
Ohhh okay, I see then. So there's not a fixed ratio of air blowing down the barrel. Hmm. I see what is happening now.

So yea, that is a major headache and I see why Blade is so concerned about the problem. So I see your point. Yes, you'd need to chrono for energy/BB weight and not muzzle velocity at the chrono station.

I guess the only other thing you could do to counteract the problem would be to reduce the poppet valve timing to the point where it would essentially spill out the same/similar volume of air that an AEG would put out. But like the post you referenced above, each gun would need to be individually tuned for that kind of performance. It's easier to just keep the valve open for the maximum or minimum times, but neither setting would give you optimum performance.

Okay, so now that we're on the same page, continue with the ban discussions, lol!

Thanks for bearing with me Jonezy. I'm not familiar with P*'s and didn't even know they could be adjusted in such a way. And now I understand how people are shooting BB's 300 feet! lol
Now you get it! It worked!

You can adjust the poppet dwell down to where the problem disappears with some simple math or trial and error. You just have to volume your barrel using the same system Angus mentioned in the post I put up except with 0.20g BBs, but that's something people will have to do on their own time since it'd take so long in a chrono line. It'd also carry the possibility of being detrimental to your accuracy if your BB isn't propelled throughout your barrel, so it falls back to adjusting your output pressure on your regulator. This is why I've been pushing for chronoing guns as they're going to be used on the field to find their muzzle energy and that way, no one gets screwed as long as people are honest at the chrono booth.

Keeping the poppet valve open for the minimum amount of time stalls the system and won't allow it to fire. Setting it for the maximum dwell *may* cause the BB to continue to be accelerated even after it exits the barrel, at least for a short while. For every idea someone can come up with to target this problem, ******** like me can come up with 5 ways to sidestep it so there is no "perfect" solution.

Again, I apologize for losing my patience but when people can't seem to see the issue at hand through the data that has been presented, it gets frustrating after a while


Quote:
Originally Posted by Darkstar View Post
Rygar, yep, I'm with you for the most part, but it's still a tough call for EO's. Two problems exist. One is really unintentional, in that the P*'s have an inherent issue regarding the way BB's behave relative to the amount of air volume entering the gun's barrel during firing. The second is the same intentional issue that PTW and ICS owners are scrutinized over, which is the ability to swap cylinders for different muzzle velocities. Personally I have a zero tolerance for the latter, though I've never caught anyone doing it. I would hope P* owners would be just as trustworthy, but the potential for exploitation can still exist. That possibility creates liability, and that's really what the EO's are worried about. They're not worried about the honorable player. They're worried about the a$$hats that cause problems, cheat, etc. But it's good that we're having this conversation.

Really this isn't an issue of Joule creep at all. It's just how the guns perform since they let a greater volume of air into the barrel. That's why I was originally confused, because creep usually refers to the boiling effect of CO2 or green gas as temperatures increase of the course of a day. Since now I know how the P*'s operate, it's a completely different problem/issue altogether.

Glad we're all learning something here!
It is still technically a joule creep issue since your KE is gaining in some form or another. Any and all ways to get to that destination fall under the same roof in my book, whether it's simply from how heavier BBs retain their energy in flight a little better than lighter BBs or how heavier BBs attain a higher muzzle energy than lighter BBs. The former is completely within the rules, though

You should have zero tolerance for the intentional, malicious cheaters because that, along with all the misinformation and half-truths surrounding PolarStars, magnets, and the people that use them, gives all of us a bad name. That's not to say it's not happening because over the course of my involvement in this thread, I can't tell you how many PMs I've been getting about different people knowingly abusing the system and being general chodes on the field with 40 RPS DMRs and knowing full well what they're doing. But like I said, for every action you take to prevent those types of people from abusing the system, there are 5 ways to counter it.

Since you've got so many people that followed guides like Angus', you'll have to grant amnesty to everyone in the chrono line if they register as having wildly high muzzle energy. Once people realize that it's a problem and adjusts their setups accordingly either by screwing with the dP setting or lowering their reg's output pressure, you ought to see a reduction in the number of complaints about unusually hard hits.

Last edited by Jonezy; 02-15-2013 at 05:49 PM.
  #148  
Old 02-15-2013, 05:14 PM
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Quote:
With the P*, there is technically no amount of "air space" behind the BB, therefore the nozzles (which I could compare to the springs) and set amount of exit pressure(another comparison for springs) in the lines are the negotiators of the power behind the BB...leading to your kinetic energy car theory.
Well, actually there is a fixed amount of air being dumped from each P* shot, that is what our dP settings are for. Another factor affecting joule creep is that with an AEG piston, the volume of air that is pushed by the piston does not come out at a fixed pressure. As the piston moves closer to the cylinder head the pressure increases. This is one reason why it's so easy to accidently overvolume your barrel with a P* - whatever volume of air you set to release on each shot is coming out at a fixed pressure.

Still wanting more info on joule creep? This post (#23) gives another (same, just different wording) explanation:

http://www.pstartalk.com/showthread....ull=1#post1350
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  #149  
Old 02-15-2013, 05:47 PM
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Oh wow, I didn't notice HS5 posted there.

Quote:
Originally Posted by hunterseeker5
So what is the ideal? Well ideally, if accuracy is all you're going for, you want your bb to accelerate, stabilize, and exit the barrel. If you're over volume you're losing potential accuracy and if you under volume you're losing potential accuracy.
This may present a catch-22 because adjusting the poppet dwell usually necessitates the adjustment of your reg's output pressure and vice versa. I have to look into this some more...

Take a gander at this:

Quote:
Originally Posted by hunterseeker5
As far as pinheads banning the P* for its "dangerous" power creep I've been saying for years, LONG before the P* was a glint in anyone's eye, that rating guns by their output, hop off, and with .2s is stupid. If you know how to tune, or take the time to learn, its easy to gain a good 10+MPS just by turning the hop on and in extreme cases almost double your KE output just by switching to high mass ammo. The solution then is to, instead of chronoing guns like a knuckle dragging chimpanzee you chrono them in the only way that is relevant: AS FIELDED. You rate your field for X joules and guns used on that field must shoot at or under that KE. PERIOD. Its not complicated, it doesn't require a physics degree to figure out, its perfectly simple.
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Old 02-15-2013, 08:31 PM
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once you posted about the "dwell" ... a lot of gear heads could relate to this.. just like timing on a car with the old points set up.. your timing how long that valve stays open.

totally makes sense on that level... and you hit an explanation there that most people will be able to relate to even if they cant fully get a hold of it.

now the issue of someone chronoing how they are gonna play?

still doesnt change a thing on that end. people who cheat, will cheat at that very point... "im playing with 20's"... chrono'd ... then in go the 43's...

not sure how chronoing with "what you play with" fixes it or what the solution is.

but you guys are making progress and getting farther along, so kudo's on that.
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