Lee used to manufacture a 120 gr. round nose for the 32-20 and it mikes .313 out of my mold cast from Lyman # 2 Alloy. RCBS also makes, or used to, a semi-wadcutter for the 32-20 and it weighs 98-100 grs. from my mold. It comes from the mold at .312 again cast with Lyman # 2 alloy. I would expect a pure lead bullet from either mold to be .001-.002 smaller. Might check into those.
I can personally attest to the effectiveness of the RCBS bullet on properly sized game for the 32-20 from a Mod. 92 Winchester and a 1st generation SAA. Great bullet.
Vic