Just bought a sp-10 thumbhole. The barrel fit into the receiver is not rock solid, it does have a little play. if you set the butt of the gun on the floor and pull straight on the barrel it doesn't move or come out of the receiver at all but if i twist the barrel clockwise or counter clockwise I do get some play not a crazy amount, but not just a tiny bit either. Is this normal with theses auto loaders? ive tightened the mag cap as tight as i can by hand and it doesn't seem to do anything. any help would be greatly appreciated.