I've got some Hornady #3120 which is a 150gr. Spire point .312 Dia. that I want to try in my M39. The barrel slugged at .3115 but that was before I got the last few layers of cosmoline out of it. I intend to start at the low end charge weight. Have any of you shot .312 dia. jacketed bullets from your Mosin Nagants? One more thing. I know many guys shoot .312 cast bullets do you change your expander ball when loading the bigger dia. bullets?