I'm new to casting (as in I've never cast a bullet before) but am good not to get into it for a specific round to start with. I have a BSA Martini Cadet in the original .310 Cadet caliber. It fires a 120 grain lead heeled bullet at about 1,300fps. I make my own brass for it and have been using the bullets from BACO made in an RCBS 310-120 mound and they cast it from 20-1 alloy, considerably softer than I'm used to in lead bullets. I lube them with Lee Liquid Alox and have noticed that after a few rounds there are considerable lead deposits in the throat and first couple inches of the bore. I'm thinking the lead may be a bit soft for the application. I was wondering what alloy I should be using to make bullets when I do, the midway hardball (16bn)or maybe lineotype (22bn)?