I have two M1A', a Squad Scout and a Socom 16. With both came an instruction manual that said both guns were cleared to shoot all commercial and military ammo in good condition. But not the higher velocity stuff like the Federal "High Energy" ammo. The headspace settings, which come with the guns show you that the headspace is set in the overlap range for both types of ammo.
What I've noticed when handloading is that the best accuracy comes with loads that are a couple of grains less than maximum for the heavier cases. I've only loaded with H4895 and TAC powders. E
