I've done a lot of experimenting with loads for the .223AI albeit not with Barnes 62TTSX...Ive been shooting the 55 TTSX and earlier, the 50 TTSX
Best velocities, and accuracy were obtained using TAC and H335....3500 fps and 3473 fps out of a 1 in 8 22 inch barrel.
H335 however is extremely temp sensitive, for me to the point that it is unusable.
TAC does not suffer from that malady and I wouldn't hesitate to try it with 62 grain Barnes.
Max load with a 55 grain TTSX is 28.5 grains for both TAC and H335
My second go to powder is IMR 4895...28 grains of it...but it only brings about 3300 FPS... and Im with you on the faster I can get a Barnes to go...
