Don't have a M1 or M1A or AR if I did you can bet I would be shoot cast lead bullets in them all, use the right bullet usually a little heavier than normal, proper dia. and BHN gas checked bullet along with a good lube or PC, slower burning powder and your set for lots of cheaper shooting with good accuracy be it at a slower velocity.

I've been feeding my three different SKS rifle a Chinese, Yugo and Russian a steady diet of 155 to 185 gr. cast lead bullets for over ten years with no leading issues before I ever started powder coating my bullets.