Chote extensions (spelling?) seems to work just fine for me, both on my 1100 and 870
Respects,
Richard
Those are the best, Tac Star extensions work well, too, but I favor Choates. I have them in 7, 8, 10, and 12, but the 12 shots are ungainly and awkward.
I used them for 3-gun matches, never had an issue.