Some years ago I bought a Winchester 1894 SRC in .30WCF. The bore was a classic sewer pipe and wouldn't shoot anything with better accuracy than around 12” at 50yds.
This month it went to JES Reboring and came back a .38-55, 5 groove .376 1:15 twist. I received an Accurate 38-250D mold, but didn't have time to cast and load any for my first range session, so I made do with LEE 379-250RF bullets cast from w-w alloy loaded in new Star-Line cases primed with Rem 9 1/2 LRP. Best accuracy came with 24gr. of IMR4198, 2.5” at 50yds off a bench. I figure this can be improved using bullets from the Accurate mold and sized bigger, or unsized. A Saeco .377 die is all I could get at the moment, and .377 was what the LEE's were sized to, they drop at .381” from the mold. I just cast some from the Accurate mold, w-w alloy at .379” cooled. I'm thinking about loading these unsized, opinions?
Any powder suggestions or loading info would be appreciated. I don't expect bolt rifle accuracy from a saddle carbine, but I'm hoping for 2-3” at 100yds. I haven't ruled out duplex black powder loads.