So far added new rocket high torque 16tpa motor. Prommy red bucking and nub. Bipod, scope, scope protector for externals. Took it too my first game. Using a 7.2 3000mah nimh battery to try to keep rate of fire lower. Gears started grinding and locked up. Screeched a few times so I stopped using. Opened it up and piston was stuck back. Not sure if that means anything. Looks to be metal shavings in gearbox. Gear teeth look shiny on ends at the edges. Going to clean out the shavings and put back together and see if it works. Pretty sure I tried shooting through a jam. Never had any of my guns jam before so wasn't sure what was happening. Bb was stuck in hop up. Opened up and gears moved fine while open. So did the piston get locked back somehow while trying to shoot? I'm not sure.