eme226 - you must be a glutton for punishment with those 3 1/2's.
I shoot an 870 Wingmaster (full) but it's only chambered 2 3/4. I use the copper-plated #5 Winchester turkey mags and it patterns well. Took a 23-lb tom last year at 37 yds.
One thing I think helps is having confidence in your gun and your shooting ability. I've shot pheasant, ducks, geese, quail, five deer, and three turkeys with this 870 that I bought back in 1979. Every time I think about trading up or getting something different, I have to ask myself why and can't come up with a good reason. If I got a gun that I wasn't happy with, I'd kick myself; so I just keep using it and it's never let me down.
(And it's ready to go again this spring!!)
Threebeards