moderator , muzzle device.
I literally cannot pump more than 3 times now because of noise. You can hear a pin drop in my garage, nothing to absorb sound it just reverberates. If i can get it to a single pump with consistent accuracy I'll do it, just because a single pump is the quietest it can ever get.
I just realized the physics formula isn't quite right because i forgot to take into account headspace. The physics formula shows an increase in velocity as valve volume decreases for all pump numbers, which doesn't match experimental results. Once i take headspace, even as small as .01 cubic inches, i see the increase for low pump numbers and decrease for high pump numbers. The reason is because the smaller valve volume builds pressure faster and that headspace really starts to have a dramatic impact. Halving the valve volume with the same headspace reduces efficiency of the pump, which has a compounding effect as you pump. So while i might be able to hit higher velocities and hopefully a little better accuracy at 3 pumps, i doubt I'll be able to just use 2 pumps now. Probably still worth doing though. I also need to reseal the pistol (it doesn't hold air overnight) and while doing that I'll check the flat top piston while the valve seal is off and make sure it's set right, and then I'll stuff the valve a bit and see what happens