hell yeah the sounds of GBB full auto in CQB is like a real wepon gets your blood flowin even when your standing still. My primary shoots at 630 but can handel over 800FPS I just dont use the full power cause I dont wana replace gears all that much, once every other year but it usualy is about a year or a little more for gears. Here the CQB coars has a 320 max so thats what my cutdown AR and my side arm shoot, about 330 or soo. What gear box doeas the saw use? Is it a custom or its own set up?? sounds like the tappet and or the spring guid is fuked. Possibly a piston problem as well. Parts are cheap but alot of time peolple work on their hardware and it never works again. personlay I think their realy simple just, very delicate oncee the gear boxes are open. I nerver Used a gass rifel, I herad the sniper gass is the way to go