I disagree with the assertion that buckshot patterns tighter with a less restrictive choke. Now I am talking about basic, no-frills, cheap Remington, Federal, Winchester #4, #1, and 00 buck. I've never used the Flight Control ammo. I've patterned all three of my shotguns, using various chokes on each and trying all three sizes of buckshot in each. Without exception, I clearly get the tightest patterns with full choke. That's my experience, but I'd think that with my "sample of three" shotguns, it would hold water.
Robert in the hills of Tennessee