Also I just finished putting in the gears and the m130 spring (figured if I had it open might as well change out the spring) but I wanted to say the Pneumatic Blowback system really sucks its more of a pain putting back together than a gearbox if I had another decent gearbox to throw in there I would cause I dont ever want to deal with that BS again. Once it goes down again I will be buying another gearbox to throw in there cause like I said before I cold care freaking less about the BB function.