need an upgraded piston
 

ok so I recently made and installed a mosfet in my gun and rewired to 16awg ... I put it all back together and did a bit of testing. Really improved the responsiveness and rps. It sounded a bit funky so I fiddled with the motor height but it didn't seem to make a difference. well long story short my piston is stripped from the 3rd tooth onwards. The gun is a VFC 416 running on 7.4 liop so its good quality.

Anyways I would like some suggestions on what may have caused this and what I should be replacing with?

Thanks!

Here is a picture of the damage

http://i824.photobucket.com/albums/z...ps0be596f8.jpg

Lonex extreme toughness
SHS 14 tooth
Modify High Speed

The stock VFC pistons aren't the greatest quality, so it's not that big of a surprise that it stripped.