I seem to recall from years ago when folks were importing all kinds of surplus guns & converting them all for US cartridges that many of the .310 bbls were too much over size for the .32-20 bullet dia. Many were I believe converted to .32 WS. As I understand it the only problems with this conversion were bbl thread dia & twist rate. Cast bullet loads in the .32-40 should be great up to whatever length the twist will stablize. Would of course check actual bore dimensions to see what sizing may be necessary for a bore fit.
