I have 4 shotguns--Mossberg 835, S&W 916-A, Rem 1100, and SLE o/u, all 12ga.
I hunt deer with the Mossberg and S&W with 00 buck. My closest kill was 8 feet, and the farthest out was about 35 yards. You didn' t say if you were gonna be using slugs or buckshot, but I don' t think I would be comfortable, personally, going any farther out than 50 yards with buckshot. I' ve never used slugs, so on that I' m not sure.