I am having problems recently with my CA M15 A4. I recently installed a sp120 spring and noticed a heavy decrease in FPS. I checked the piston and what not and it seems to be fine. After resembling the gun again, it fired well in semi; however, it would jam after firing a few rounds in full auto. The motor will try to turn, but the gears won't move. Upon further investigation, the gears in the gears do turn when I manually move it with a screw driver. finally
did that. Tested on two battery as well.
possibly a motor problem. drop the spring. then test the gun
What kind of battery are you using?
NiHM Rechargeable Battery
Your rifle likely locks up after using on full because the piston is stopping partly pulled back at some point between firing. With the setup in your gearbox, your motor, and the battery you are using you're just not doing the job of pulling that spring effectively. It's possible your motor could be on the way out. It's also possible that cleaning up and reshiming your gearbox may reduce the load enough so you eliminate this problem. A torque-ier gearset would also do the job. A 9.6 mini or nunchuck may also solve your problem.
[quote="MuMuLi"]Will the motor effect accuracy/ FPS?[/quote]