I have one on my 870. If I were to do it over again I probably would have bought a "Rhino". My dad has one on his 870 and that thing is worth every penny, plus you can shoot hevi shot thru it. The older "Kicks Gobblin Thunders" you can't, don't know if that has changed. But if you ever think your going to shoot "hevi" make sure the tube is made for it.
I've shot many birds with the "gobblin thunder", the only reason I don't like it ALOT, is I think it should hold a better pattern at long range (40+).But, that is probably because I bought one that was to restrictive. Don't know what restriction it is, but it's tight. If you want to know p.m. me and I'll look into it.