I'm thinking it's Accurate Powder's new letters/numbers for their old AA2015br. its short grain extruded powder that goes through a measure real well. I used it years ago in a bolt 223 gun. Looks to be close in the burn rate chart to RL7 and BenchMark.

Last edited by 222Sako; 01/26/13.
Then you will know the truth and the truth will set you free.
John 8:32

A lie doesn't become truth; wrong doesn't become right; evil doesn't become good, just because it's accepted by the majority...Rick Warren