ORIGINAL: BS
My slug shooter is a 54 with a 1-36 twist that shoots BB 460s.......90FF is the most accurate load...........one of the secrets to shooting BB is, the barrel maker sent me the extra lenght of barrel to make a swedger with. With a couple of wraps with a mallet, I can have a BB bore size. You just have it spin them on the bore till the groves align, then down they go.
Cool! You know I've though about doing the same thing, but I haven't figured out how to get the extra length of barrel. Maybe I'll call NEF about that. Nice to know its working for you.
Happy Hunting, Phil