I just sent a barrel out to Mike Orlen (who turned it around in one day!). I had an old 18" park'd barrel from an 870P that I thought would be more flexible in terms of being able to get the best pattern if I could choose between cylinder and IC tubes (small difference, I know) and while it was out for work I asked Mike to lengthen the forcing cone (which arguably will do more for pattern density than choke selection...). I've also found, with my FN SLP, that using a rifled tube dramatically improved 50 yard rifled slug performance without having any effect on 10-15 yard 00 buck patterns, so that's another version of the flexibility that tubes can provide. Mike Orlen's work on this barrel was beautiful, by the way, as well as fast and economical. Big thumbs up for him, if you're thinking about that kind of work.