I picked up one for my BPS. Called a "long range full" but I do believe it's IM. Forget the actual constriction. It throws damn near a 100% pattern @ 30yds with Rem Hypersonic 2's. Fasteel 5's have a working pattern @ 40. That's a light load out of a 20 for 40 yard shooting, but I was impressed... Follow the above advice. I looked into getting a Briley before I picked up the Carlsons and they do the same thing. Charge a premium on top of it... for the same choke, just a different title.