I spent years when I was younger using a 28" barrel 12 ga with a modified choke. It was hard to hit anything with that. I finally got a 26" over/under double and put improved cylinder in the top (first) barrel and modified in the bottom barrel. My hit rate went way up. I also use high brass size 6 shot for squirrel and grouse. I use low brass 7 1/2 for dove and quail. I still use the same chokes though. I have killed 2 turkeys with the gun using 3" magnums with full choke. The last turkey was at 40 yards.

**Disclaimer** I am by no means an expert as I mostly deer hunt so hopefully other, more experienced shot gunners will chime in.