6.6.2 HOW TO RELOAD FOR THE M1 RIFLE
My cast load for the M1 was developed when I was a poverty-stricken undergraduate student in the 60's. Bullet was 311284, cast out of wheel weights (which were much harder in 1968 than they are today); Hornady gas checks, the then new-fangled Alox-Beeswax lube; and they were sized to .309 for my rifle. Powder charge was 42 grains of WW II surplus 4831 that was sold by Hodgden for $1 a pound; less if you bought it in bulk. Over the charge was 1/4 sheet of TP; old FA or WW II contract ball cases; CCI 200 primer. The bullets needed to be seated deep (to the "dirt groove) in order to fit in the magazine. There are a few "rules" violated here: powder allegedly too slow for M1 gas system, bullet too heavy; bullet seated deeply into powder space. The charge is so light that the op rod seems to get a long gentle shove instead of a sharp push. I never had any difficulties with it. Like wise, the deep-seated bullets did not seem to seriously hurt grouping. Groups (fired prone) went about 2-1/2-3" at 100 yards, about the same as the M2 ball that was around then. (this was not a "match" rifle) I may have had one or two failures to feed in the hundreds of rounds that I fired. I used to break it down and clean after shooting this load; and I would usually find a few flecks of lead on the gas piston that would brush off with an old bronze bore brush: I cleaned the gas cylinder with a 16 ga shotgun brush and patches, and never had a lead problem there.
Today I would start with 40 grains of new-production 4831; if you are using post-1970 wheel weights, you will probably need to add some type metal to it. One thing you must never due with the M1: never, ever load the bullet to engrave in the throat. You will be asking for a slam-fire and the results won't be pretty.
BTW, the same load tweaked for the 03A3, and shot at 200 and 300 yards, got me my first Master classification in 1973.