Just picked up a 930 pro series waterfowler, 12 gauge. Looking forward to breaking it in. As always, I broke the gun down for a thorough cleaning upon getting it back home. I had noticed before taking it apart, that there was slight play in the barrel. Almost like the magazine cap was loose. Thorough cleaning, re-assembled, tightened mag cap, tight, and barrel still has a slight "looseness". First Mossberg, but all my other semis and pumps lock up tight. Is this normal, or should I be sending it back for work?