4895, H or IMR, and cci #34s is a popular combo. I use Varget and cci br myself. BL-C, rl15, win748 are popular too. Most medium burn powders will work fine.
I did some load testing with my SA M1A a while back with Hornady 168 gr. AMAX bullets and also the 155 gr. SST bullets. I got my best grouping with the 168 AMAX....the 5-shot group came in at 1.020"
Here's the 168 gr. grouping......
The best 4 shot grouping with the 155 gr. SST was 1.055". My stock slipped off the rear sand bag for the last shot & sent it up high!!
Here's the 155 gr. grouping.....
Keep in mind, my M1A is a standard model.....nothing special, so I was really happy to get these types of groups.