I've just requested info on a new .50 barrel from Track for my 4140 Italian-actioned Sharps. Presently, it has an original 1859 percussion barrel, re-lined and chambered by Sharps in 1868 under government contract.
; The original lined barrel has the 42" twist, common for the day. Too bad it didn't have the other twist used and present on some .50/70's of 1 turn 1 in 24". If it was that one, I'd keep shooting it. It will shoot into 3" at 100 meters with it's original battle sights, with a shortened 450gr. Lyman bullet, original style and BP.
: I will chamber it for the .50Alaskan, probably, due to my stock of .348Winchester brass. I think I can live with 500gr. at almost 2,000fps and 600's close to 1,800fps. I expect they will work well on the beasts of this province.
: Quite possibly, the #4 taper blank, just over 1" in diameter and 35" long, would be a good one for the liner job you're doing.
: I anxiously await word of the double .50x2-1/2", Colorado. I do hope they don't use the 56" twist .50/110 barrel for the liners.
: Track does sell an 11/16" dia. liner in .50 with 1-24" twist, but it is undersize to line a 12 bore, at only .687" dia. It might line a 16 bore OK, but that would make for a thin liner turned to .662".
: I'm not sure what sort of pressures a 12 bore double can take as they only shoot 12,000LUP max pressures in shotshell ammo. I'm sure many aren't designed for much more than that. Perhaps, Browning and Rugers are annomolies here and are suitable as are the Ruger over/unders.