The real issue with the M1A is the OPERATING ROD part of the gas system.
If you use a powder with too fast a burn rate, it throws the gun out of proper cycle speed, and bends the OP ROD.
The ONLY powders I have ever used for my M1A has been IMR 4064, and IMR 4895, with my favorite being the IMR 4064. Both have a perfect burn rate for the gas system of an M1A.
Refer to your load data book for how much to use with whatever bullet you choose. When in doubt, call the powder manufacturer for load data. They'll be delighted to get you start and max loads.
BTW, lots of good info (general knowledge) over at m14forum.com