I load my own ammo and as was said above, 4064 and 4895 are top powders for the M1 for 150, 165 and 180 grain bullets. Don't load it hot.
I also use 3031 for my loads with 220 grain RN bullets and it's worked flawlessly and I used it to kill elk and bears in the past. 220 gr Bullets chronograph at 2370 FPS with 42.7 grains. Those are very deadly when used on all the game I ever shot with them, most of which was shot between 30 and 150 yards.
I have had mine since about 1980. I glassed bedded the receiver. Other then that I have not done anything to deviate from GI specs and I have never needed to.
I just killed my 2020 Antelope buck with it a few weeks ago. Still works perfectly.
