What is your pet load for 150gr pills? I would be fine with refilling brass for it.
I don’t shoot the M1, I’ve got an M1A and use only the 168 gr Sierra BTHP Match bullets. But I keep them right around 2600 fps so as to keep the pressures down. I could push them faster, but the rifle isn’t built to take that.
When I don’t have those I use the 146 gr. FMJ stuff from Winchester. That’s just about an exact match for the mil-surp stuff.