...bought a Cooper-T bolt for his PGP, and he said he had a hard time getting it in the gun. I figured he had just done something like this guy, and I didn't think much of it...till I tried to pump his PGP. It was WAY harder than the original bolt to pump. I'm guessing that something was off internally in the Cooper-T, so that even when the rear part was retracted, the balls weren't fully released, and were pressing on the inside of the brass. I told him to return it, but he never did. I guess it'll eventually loosen up...as those balls press grooves in the inside of his gun!