"ALL" barrels will pattern 100%. Some just have to be patterned a lot closer to the muzzle. As I recall Starr was speaking of the standard 30" circle at 40 yds. If that's your criteria sounds as if you should be doing those barrels for the Trap Shooters. 100% from a cylinder bore "Fantastic" (refined version of BS)

Stan; in full agreement if you have the wall thickness then my choice for a ML'er would be the jug chokes due to the loading factor you mention.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra