Friday I was chronographing some rounds and had a .223 with me so ran some of them over the screens.
Two 3 shot groups, 26.0 TAC, Sierra 53 HPBT, WSR primer.
First three - high of 3211 fps, low of 3209, extreme spread of 3 fps.
Second three - high of 3207 fps, low 3201, extreme spread 6 fps.
Six shots total with an extreme spread of 10 fps.
Not saying other powders won't produce good results also - good ol' IMR4198 is still an excellent powder for accuracy in the .223, but once you get TAC up into its optimum pressure range it produces very consistent velocities and great accuracy.
