[Azathoth]

I just went back and looked more carefully at your picture. You can see that the teeth in the middle of the piston are in pretty decent shape but the second tooth (the one after the pickup lug) and the third and fourth are also fairly banged up. Go and check AoE,

You may not need to remove the second tooth of your piston to give enough clearance for your sector gear to pickup the piston.

Also your gun may be cycling too quickly and the sector gear is catching the piston somewhere between the lug and the first 3 teeth