I'm back up at the moment, don't know how long it will last, here goes....
jeff223, I'm sure it would shoot a jacketed bullet great, my 30-30 is a .310 groove diameter and it shoots several jacketed bullets into 3/8" groups. The barrel does seem a little long, but it doesn't seem a hinderance either. My 1885 Browning had a 28" barrel and I never felt it was a hinderance. And yes, it is drilled and tapped in the standard Handi pattern. I took the rail and scope off my 45-70 and stuck it on this barrel, no muss, no fuss, no alligator puss.
Somerled, it has been suggested that I try turning the neck down a few thousandths, I can use the shop lathe to do this as an experiment, but what I'm doing is working very well, and it only adds another step on the press, not a big deal at all really, and I see little difference between turning the case neck and resizing the loaded case, unless one were trying to shoot a bullet that is larger by .002" or so. If what I'm doing were not working I would persue neck turning with much greater vigor. As things are....
??
cabezaverde, .379 seems this is the largest diameter Lyman or Rcbs offers a sizing die in for this caliber range. I'm sure one could be opened up, but when it is considered that I'm sizing down another .002" after the case is loaded, I'm not sure a bigger bullet would help in anyway.