Post
by Iprenen » 27 Aug 2018, 06:23
[quote=Majk post_id=77393 time=1530962920 user_id=851]
Joule creep is the biggest problem. My P* M27 is 301fps @0.20 and 348 fps(equvalent) with 0.30's.
Majk, his readings are probably not off. I've seen similar ones before. It depends on a lot of factors, like barrel length, air pressure, hop-up setting, bore diameter.
The serious thing here is that if you tweak these parameters, you can have an even larger difference in the readings and it would still be classified as field legal at Berget with the current rules.
Well, if he measures at end of barrel the fps should go down and the Joule should go up with heavier BBs, it's the same size and geometric form, the only variable is weight. I seriously doubt he can break the laws of Physics...
I assume he has the same configuration of the gun otherwise its not a valid test at all.
A qualified guess, if he has done his test right and only changed the weight of the BBs, he might have mixed up the fps readings... If thats the case I get 13% Joulecreep which sounds quite reasonable.
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Not at all: Joule creep is about the efficency of a gun. With HPA, GBBR, bolt snipers and Semi snipers, you often have a bigger air volume being released than the air volume in the inner barrel.
This means that when you chrono a gun with extensive air volume with 0.20g bbs, the bb will have left the barrel before maximum pressure has been obtained, meaning that alot of energi goes to waste. If you then utilize .3 or 0.43, the bb stays longer in the barrel (mostly) and absorb more of the energy before leaving the barrel and as a consequence, have been joule creeped.
I agree that he can't break the laws of physics but the law of energy of a moving object does not take the acceleration of the object. Newtons first law (M*v^2) is only a point in time measurement.
Newtons second law (m/s/s) is the one introducing joule creep.