[Red62]

I'm thinking that it might not have strong enough springs for the Tappet, the contact and the anti-reversal for the 11.1V battery: rapping the voltage 150% like that will also put 150% stress on your motor's coils. When you add in the resistance from the piston spring, it'll also add a few more percentages to that load. With parts spinning faster, the time for things to travel have to decrease too in order for them to work, but doing that will require more tension and more friction on your parts. Unless the thing has a heavy amount of grease on it, it may also cause faster wearing.

Personally, I'd either stick to the 7.4V LiPo or get one of those sector gears that pre-cocks your piston or partial cocks it so that the time you have pulling the trigger to when it fires feels much closer and it'll reset sooner from displaced reaction time.