Welp....after a week of fiddling around, I've settled on a charge of 18.5gn of W296, COAL of 2.160"
I'm getting an average 2140fps, not the hottest load under the sun, but giving .75moa 5 shot, 100yd groups, I'll take accuracy over velocity every time.
They're shooting 3" lower than the TAC Tx...