Between 25-26grs of Ramshot TAC powder usually shoots well in most any 223 (bolt action or AR-15) with 50gr H-Vmax or 50gr Nosler BT bullets.
I usually start at 25grs and work up .2grs at a time shooting groups until I find a sweet spot with a new rifle/barrel.
Generally best around 26grs; Tac burns pretty clean and is not to temp* sensitive either.
Has shot good with both Winchester & Remington brass & several type primers(CCI, Win., Federal).
If using military brass may need to reduce charge due to thicker brass (less case capacity).
For AR-15 just load to magazine length with no crimp.
Good luck,
Ted