So.... this has been baffling me for a while. I have an CMYA M14, with upgraded motor, piston+piston head, and air nozzle. When I test compression its all pretty good (I know it could be better but I'll live with it). However here comes an the issue................ when I put the gun together I get about 190 fps if I load a single bb in the magwell or use a magazine BUT if I muzzle load the gun, tilt it back until I hear the BB make a seal, boom! 410 fps (which is what I was expecting)
So in summary:
(high cap) Magazine = 190fps (no hop set)
Muzzle Load = 410fps
I've tried this with different bucking, changing the hop, rhop even. its consistently bad
the best improvement has been trimming the lips off a bucking, I then get about 330 fps if I muzzle or mag feed the gun.
ideas anyone? I did try a google and haven't seen anyone else with this issue