I know you are asking about TAC powder loads in a .223, but I pretty much exclusively use Sierra bullets in shooting paper. Just last week I loaded some 69 gr SMK bullets seated .001 into the lands being pushed by 25.5 gr of H335 w/CCI 400 primers into my Savage Model 12 VLP bolt gun. Had very good results @100 yds with 5 shot groups at or under 1/2". That was the best success I've had with shooting 69 gr SMK bullets in this rifle that has a 1 in 9 barrel twist. TAC unfortunately, isn't listed in Sierra Manual for this bullet. Good luck!