If fire-lapping, use jacketed bullets fired at low, very low, velocities. The jacket and the low velocity will largely prevent the bullets from obturating/expanding into the throat area.

Check your groove size, it's probably too large for reboring to 9.3 but would probably be fine for .375 (9.5x57/375 Express).

Check the crown; a recrown may, just MAY, improve accuracy.
Regards, Joe

You can lead a man to logic but you can't make him think. NRA Life since 1976. God bless America!