AGM M14 Low FPS

[mateba]

Hello,
I have an AGM M14 with a few upgrades.
Guarder SP130 spring
Guarder Infinite torque motor
Guarder metal bearing spring guide
Guarder cutoff lever
Deep Fire hard bushings
Prometheus Aero cylinder head
Prometheus air seal nozzle
Prometheus hard type bucking
8.4v 4500 Elite w/ Deans
Mosfet w/ AB
No selector plate (semi only)
V2/3 torque gears on the way

I don't have a chrono but I can not punch through the bottom of a coke can. I checked my compression and its great. I don't know about the nozzle to hopup but the hopup to barrel should be fine sine there is Teflon under the bucking. I'm getting the feeling its the hopup chamber design.

Has anyone had FPS issues with this AEG? Easy fixes?

thank you for your time,
mateba

[Caped_crusadar]

it must be an air leak, make sure the holes in the piston head are free of grease, check to see that the nozzle fits with the hop up rubber snugly, and the cylinder and the cylinder head fit snugly