my first experience of cheaters with hpa guns

[Sacarathe]

my gun shot at 340 and has a good range but these guys were firing well beyond my range and it still felt like getting stung by a bee through my trousers.

i asked one what fps he was at and the reply was "dunno"

 

Flat-hopped high airvolumed widebore HPA guns are known to shoot [25%+] further than AEGs on the same muzzle force though. I'll believe it when I see it mind you. Not knowing your FPS is pretty shameful.

[Samurai]

Because of joule creep. Not knowing his FPS suggests that it's deliberate.

[Sacarathe]

Because of joule creep. Not knowing his FPS suggests that it's deliberate.

 

Yep, this be why you shouldn't chrono HPA on .2g

 

@OP next time, ask them (any HPA user) their BB weight instead - if it's anything above .25, ask them what weight they chrono'd with and if they say a number below .25 report them immediately*.

 

*if you have existing reason for suspicion

[skarra333]

 

Flat-hopped high airvolumed widebore HPA guns are known to shoot [25%+] further than AEGs on the same muzzle force though. I'll believe it when I see it mind you. Not knowing your FPS is pretty shameful.

 

 

 

Yep, this be why you shouldn't chrono HPA on .2g

 

@OP next time, ask them (any HPA user) their BB weight instead - if it's anything above .25, ask them what weight they chrono'd with and if they say a number below .25 report them immediately*.

 

*if you have existing reason for suspicion

 

Sorry chaps but can you expand on this - or direct me to a link with further details?

I was stood behind a Tippmann M4 chrono'ing last game and the site did it on their own mag/0.2's - and that was it, it all seemed sufficient at the time. Should there be additional checks/calibrations to accommodate for something then?

[MrMcG]

 

 

 

Sorry chaps but can you expand on this - or direct me to a link with further details?

I was stood behind a Tippmann M4 chrono'ing last game and the site did it on their own mag/0.2's - and that was it, it all seemed sufficient at the time. Should there be additional checks/calibrations to accommodate for something then?

 

 

In short joule creep is when -

 

Using a heavier BB the FPS of the rifle increases, instead of doing what you would expect ( dropping as heavier bb ) so this FPS of the heavier BB then can be translated into what the FPS would be with a .2.

 

The gun should be chrono'd with the heavy weight bb and set then locked at that point.

[proffrink]

This might also help a bit as a precursor to what MrMcG is saying: http://www.airsoft-forums.co.uk/index.php/topic/28694-what-sniper-to-buy-snippaawiffaaa/?p=218860

 

If you understand what muzzle energy is then explaining Joule creep is easy: Muzzle energy doesn't stay the way you'd expect it to because heavier weights stay in the barrel longer and have more energy transferred to them in that amount of time, so their muzzle energy is higher than that of a lower weight BB. HPA uses high volumes of air and this exacerbates the issue.

 

Sites don't crono properly on the highest weight that someone will be using (as they probably should be) so Joule creep kicks in quite often. Especially with so many people going as high as .30s in fully automatic gats.

[skarra333]

Crumbs. I had no idea, I'll be watching for this at the chrono in the future. Thanks for this.

[Sacarathe]

Crumbs. I had no idea, I'll be watching for this at the chrono in the future. Thanks for this.

 

I did say something misleading above, should probably correct it somewhat, though I said HPA guns should* be chrono'd on 0.3g, the results are irrelevant if the owner uses exclusively any other weight, in which case they should be chrono'd with that, but the 0.3 thing is a general rule for simplifying things, because (I guess) 0.2g, through 0.3g is much more common than >0.3g.

 

I used the example above because of just that: common weights.

 

Ultimately, all airsoft chrono'ing should be with the weight the player will use, but simply by the fact that we chrono, and by the large numbers of guns which always fail - even to owners who're sure they wont, means that it's not practical to fire say 5-10 shots with the player's own BBs, then load site BBs in the weight the player says they have and repeat, and then IF the results match, then check the Joules.

 

Any reasonable site should allow any player with ANY gun to use BBs lighter than whatever they [passed] chrono with.

 

 

 

*convention has formed in the US

[Bencupra]

Ban hpa because of a few idiots and to be fair this comes down to the site aswell. Did they chrono guns? Tournament locks are available if there is a risk of people altering fps. All boils down to people being sensible I personally would have been having words if someone used full auto in my face at close range.

[Bencupra]

Might sound silly but do hpa weapons carry energy for longer in the bb? Mine chronos at 330 but they sound loud still when they hit an object and they do hurt apparently.

[Sacarathe]

TL;DR Always chrono with the weight you will use for the day, with the hop set - no more issues.

 

Might sound silly but do hpa weapons carry energy for longer in the bb? Mine chronos at 330 but they sound loud still when they hit an object and they do hurt apparently.

 

Do you play with the same weight of ammo as you chrono with? Did you read proffrinks post above, pretty much covers it? :) :)

 

Simple answer: No. Complicated answer: No.

 

Actual answer: any excess air discharging a BB is wasted, if you put in a heavier BB, as that BB will stay in the barrel longer, some of the excess air will be applied to that BB. Thus that BB will have more active forces applied to it than the lighter BB, thus it exits the barrel with more force. HPA guns have, relative to AEGs - unrestricted access to excess air.

 

 

 

 

 

It is well established that a heavier BB will hold it's energy for longer, in AEGs there is a general trend (due to cylinder volume) to follow the various tables for predicting the muzzle velocity of various weights of BB when you chrono with any particular weight.

 

However due to the way in which the force is generated in a HPA gun [Read: Options] and the intrinsic fact that a heavier BB takes longer to leave the barrel as it needs more applied force to get moving the same does not occur.

 

The problem is not an issue of some kind of magical hot gun effect, joule creep can only occur when the player uses a BB weight other than which the gun was chrono'd with. (or modifies some other aspect of the gun post chrono - but I would consider that cheating not joule cree: vs using a different weight being just ignorance.)

 

The problem is as proffrink basically said above, a heavier BB will remain in the barrel longer than a lighter BB - In HPA guns , relatively speaking (vs an AEG), the method of propellent is fairly infinite/exponential.

 

The easiest practical example is that an overvolumed HPA gun firing a high PSI can propel two different BB weights at the same muzzle velocity - but the heavier one has the most energy. If you chrono on the lighter one, and then user a heavier one to play, that's a hot gun.

 

Now don't get me wrong, for the most part a HPA gun can be set up to operate to a similar table of predictable velocities, but it's not necessary and it has been demonstrated that HPA guns operating in this manner are more effective than not.

 

All the faults with HPA lie at the chronograph - cheaters will always be cheaters and HPA makes no difference to that, but to chronograph players with any weight other than what they will use - that their hop is set for, is the mistake.

[Bencupra]

I chrono with the BBs I'm using and it was 330 on .28s

[ImTriggerHappy]

I chrono with the BBs I'm using and it was 330 on .28s

Thats over 380fps on 0.2's so you were running hot if the limit was 350fps.

[Bencupra]

Really I told them it was 28s and he said don't engage at close range so I said ok didn't say it was over. So what should it be on 28s? And I can dial it down for next game. Need to get myself a chrono.

[proffrink]

[Bencupra]

So it should be 270 on .28s is that right?

[ImTriggerHappy]

Really I told them it was 28s and he said don't engage at close range so I said ok didn't say it was over. So what should it be on 28s? And I can dial it down for next game. Need to get myself a chrono.

Its difficult to say for definite but I usually find its about 55fps difference between 0.2 and 0.28. But it can vary between types of gun and how they are set up.

[Bencupra]

I'll have to have a play around with it on the chrono and see what it is. Was the first time using it. I've got the flow restrictor aswell as people had trouble getting them under without it will get it sorted before next game.

[Hudson]

It should be about 295fps on .28s, iirc.

[Bencupra]

Cheers mate I'll take the Allen key to the chrono with me on Sunday and turn the old girl down.

[mimozine]

thanks for the replies guys. glad its not just me thinking their a bunch of muppets,

[Sacarathe]

thanks for the replies guys. glad its not just me thinking their a bunch of muppets,

 

So, really the thread title should be about the arses the thread is about and not HPA, throwing fuel on the HPA hate fire?

[proffrink]

I'd hate to speak on OPs behalf, but maybe it's possible he was just frustrated at having his day ruined? Hopefully his opinion of the site and players is now slightly more disconnected from his opinion of HPA, but it's a bit unfair to go after him about his title.

[Sacarathe]

 

So, really the thread title should be about the arses the thread is about and not HPA, throwing fuel on the HPA hate fire?

 

I'd hate to speak on OPs behalf, but maybe it's possible he was just frustrated at having his day ruined? Hopefully his opinion of the site and players is now slightly more disconnected from his opinion of HPA, but it's a bit unfair to go after him about his title.

 

Aye given my usual gusto about titles, I can see that my post could be presumed to be a suggestion. Nothing wrong with the title, just wondering if the OP is willing to concede it's the people not the tools. I simply meant that, as you have indicated, the OP might want to clarify post 46 on whether he gets that HPA is not the problem.

 

It's like comparing gas and electric cookers and saying I don't like electric cookers because I burn my tongue on the food more often.

[ImTriggerHappy]

 

 

Aye given my usual gusto about titles, I can see that my post could be presumed to be a suggestion. Nothing wrong with the title, just wondering if the OP is willing to concede it's the people not the tools. I simply meant that, as you have indicated, the OP might want to clarify post 46 on whether he gets that HPA is not the problem.

 

It's like comparing gas and electric cookers and saying I don't like electric cookers because I burn my tongue on the food more often.

How about the fact that the biggest nobs who overshoot and generally take the piss are drawn to hpa?

 

Its not that hpa is the problem its just that it has become the weapon of choice for the wrong sort of players and that rep is now starting to tar all those who use it correctly.