I had been using #5 Heavy Shot in my old 12ga 870 pump (3" max). 7 years ago, by accident, I tried Federal #5 turkey loads and have been using them ever since. What I had thought was a good pattern with HeavyShot, was even better with Federal. When I bought a 20ga 870, with the same 21" barrel for my daughter, I just naturally got Federal #5, and it patterns better than my 12ga.