Black hills 77 gr OTM. While I've had a true 1/9 shoot the 77's and never seen a 1/8 that wouldn't, all mine are and will be 1/7.
MM, it was a minumim spec chamber, made segregating brass and loads a must. I could run a 1/2 a grain more powder in other guns I had. It still reached velocity with less powder but I'm want to like to standardize.
