Nice Rifle!
I have had good luck with TAC in my 223s, from 22 to 16 inches in barrel length. Low extreme spreads and great accuracy are the norm. I shoot either the 55 sierra GK softpoint or the 55 NBT over 26.0 grains of TAC and the accuracy is wonderful in several rifles. This load is a few tenths over max but velocity is in line and no pressure signs in my rifles but work up accordingly.
All of that being said, in the last few weeks I have been playing with Benchmark and for 55 grainers and under this may be the powder for me, Its worth a look. I am getting good velocity and unreal accuracy.
