3'' 870 Express with a modified choke, Kent Fast-Steel loads work for me and I also use 71/2 steel for the cripple shots when needed.
I have often considered upgrading my shotgun, but I think of all the abuse I put them through afield and in the marsh! you cant beat the 870 for Durability and reliabilty.
My 870 has been to the bottom of Sapowet Marsh in RI,
and dragged through the Virginia woods for 60 yards by a 4 pointer!!!
(No Joke) I had just finished securing my climber to the tree and was getting ready to lift my gun and backpack when the deer appeared under my tree, well he walked into the parachute cord I was using and it became entagled in his antler with the gun & backpack snug under his front quarter and my end was tied to the treestand, after hanging on for dear life for about 30 seconds I cut the cord and off goes the deer with my equipment. I found it 60 yards later hung up in a barbed wire fence.