I'm one of the last guys around shooting the M1A (Supermatch, heavy 1:12" Kreiger)
For 200yds and less I use:
125gr Speer TNT, 41.0gr IMR4895, WLR, LC90, 2.75"--2430fps at 80F
For 300-600yds:
155grAMax, 42.0gr SurplusIMR4895, WLR, LC90, 2.84"--2926fps at 112F (really hot load, really hot batch of powder--2750fps would do just fine).
Everyone else (who shoots an AR15-A2 config with float tube, match sights, 1:7-1:8" twist, match trigger). 24grs Varget with the 80grSMK is popular at 600yds.