53.5 gr of IMR 4831 has proven to be awesome in my 270. Actually, I can load 51.5, 52.5, and 53.5 gr of IMR 4831 and still get around an inch out of all of them. I have only ever tested 140 Accubonds in mine, they were so accurate I couldnt see trying anything else. I am getting an average of .75-1" with the 53.5 load depending on the weather.