i figured out why my 870 was shooting a little off center inoticed my bead sight wasnt straight up it was tilted to the left a little when i loosened the magcap the barrel kinda shifted back where the bead was now straight up i had twisted the barrel a little when i tightened my magcap i had my fingers around the barrel and cap causing the barrel to be tilted a little i tightened the cap back just snug by just holding just the cap and not putting any pressure on the barrel accidently with my fingers or thumb i guess this makes sense/ live and learn i always say/ now it shoots straight