Something else comes to mind regarding accuracy. I've done most of my slug shooting with a single shot gun so pretty solid platform.
A few months ago I bought a Mossberg 500 which so far I really like but... the barrel to receiver fit was very sloppy. Probably makes little to no never mind for shot but for slugs i think so.
I decided to try the "recommended" beer/pop (soda) can shim. I found it hard to make and too fragile so went to brass shim stock. Worked great and nice snug fit. I haven't shot it enough since to note tighter groups but it was sloppy and pinning or shimmying is recommended by many.
Longbow