Creemag Running Classic valve on LP tank

now i finally got the macro for my Latest build and i thought id try it with the classic valve as thats what i am going to run it with, anyway i only had a little air in my lp bottle (about 500psi) and it seemed to shot 14bps fine before i run out of air :) going to re-try with a full bottle and a chrono as im not sure of the shoot down effect it will have.

Now i know a classic valve can shout 15-16bps with 850 input but does any one have any thoughts on the LP side of things, only reason i ask is it saves me swapping out shims in my reg evertime i swap guns :)


http://www.youtube.com/watch?v=KGHPwMGVEOc&feature=plcp

That its a sweet mag :eek:

What is the output on your LP tank?

Im kind of wondering the same thing with my invert mag..
Ive been thinking, with a lighter return spring on the bolt, lower pressure would work on a pneumag, which would allow lower LPR pressure..

another nice creation renie

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Originally Posted by DarkApollo

What is the output on your LP tank?

Im kind of wondering the same thing with my invert mag..
Ive been thinking, with a lighter return spring on the bolt, lower pressure would work on a pneumag, which would allow lower LPR pressure..

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LP is running a blue crossfire reg think they push out about 500psi

I'd say you need a minimum of 650psi (medium pressure) reg output to get it to cycle ok Renie. You may still see shoot down or chuffing at high ROF though.

If your LP bottle only puts out 450/500 (ish) psi then I think it's a non-starter for the classic valve.

You might get away with a low pressure tank on a level 7 mag with an 11" non-ported barrel. They operate at around 350psi in the front chamber with the perfect barrel length for optimum efficiency. As soon as you put a level 10 on it, even with the gold spring, you increase the operating pressure in the front chamber up to at least 400psi or more, which would require about 600psi to proper charge at rate that would prevent shootdown and chuffing. If you use a longer, stiffer bolt spring the pressure requirement is even higher. If you use a ported barrel, the pressure requirement is higher again, because you are loosing efficiency.