[Dirty Deeds]

He ran the gun stock, then upgraded, notice the metal bushings?

With that set up, be happy the piston jammed, and you didn't blow the front of your mech box out of the barrel.

First off, did you shim the gears properly? The other guys are right, lose the metal piston head, and buy an after market piston. Make sure you have a 120 or less spring.

A good purchase would be a bearing spring guide, a 110 spring, aftermarket piston, and a systema silent piston head set. Your mech box will thank you in the end.

Oh and make sure you shim the gears properly ;-)