I have a very tight chambered M1A Supermatch. I shot the 155 AMax for about a year. I think the long bearing surface drives up pressure, so if you use 155 Sierra data, you'll need to back off 1-2grs.
155AMax 2.845"
41.0gr IMR4895
WLR
LC90 case
I got about 2850 FPS out of this.