if you shove an 11.1 in a gun which isnt made to withstand it, it will destroy the gears. you need to get new motor,gears,piston and then you can use an 11.1 without it shredding gears but im sure some other guys will know more on this stuff but thats my understanding on it!
^this, not forgetting a MOSFET of some kind to prevent electrical arcing which will mean the motor turns over twice on semi (effectively firing 2 shots instead of 1)
If you're upgrading anything, it should probably be everything. For higher ROF specifically: gears, piston, piston head, cylinder head, gearbox shell, motor, wiring, battery, tappet plate and a mosfet...
