I have an 870 with a .665 IC choke. First year I shot 3" 2 oz 4x5x7's. Last year I moved to 3.5" 2 1/4 oz. 4x5x7's...both heavy loads. The pattern I'm getting with the 2 1/4 oz. is really good and I'm really happy with it.
However, I went today to by another box and did some reading on the newer Mega Heavy shells. The Nitro book tells me to shoot the MH521F (3.5" 2 oz. 4x5x6x7). I'm buying for me and a friend with the same set up so I buy what we shot last year H510H and a box of the MH521F. I hate buying a full box without patterning but what I'm shooting now, that works, matches what Nitro says I should shoot in the Heavy load, so I'm hoping same holds true for the MH. Any comments? Thanks!