I'm getting a new AR upper in .223A.I. and am wanting to know if any of you have tried any of the newer powders? Even the not so new ! What I'm looking for is accuracy and speed with 55gr. bullets in a 26" barrel with 1/14 twist. I know Accurate had a blend that would give 3650 fps in a rig like this; but they changed something and it won't do it now. It was very accurate too. I'm thinking TAC, Benchmark or 10X may work;but I sure would like to hear from anyone who has achieved 3600fps accurately with a like barrel set up. Anyone ? What was your load and results? Have you had success with 60s?