Try different shells with a couple of chokes I have a 870 super mag as does my buddy. We each bought 2 choke tubes and each bought different ammo to defray cost and multiply our chances at finding a pattern we liked. What we found was the same guns patterned differently with same choke ammo setup. We also found some of the 3 1/2 inch shells actually blew holes in the pattern not to mention are a bit tough on the shoulder. Ours were better with just 3 inchers maybe yours isn't. But the heavy shot was worth the extra cost hit amazingly hard. Knocked over the target we where shooting at were as regular ammo didn't maybe just got lucky seemed to be a much more solid shooting shell. Good luck, try to find someone to buddy up with it does save a ton!