I had a model 70 featherweight in .223. Factory twist was 1-12 as was standard for the .223 at the time. Lots of good deer capable bullets that will stabilize in a 12 twist including 50 gr. Barnes TTSX, 53 and 55 gr. Barnes TSX, 50 and 55 gr. Hornady GMX, 64 gr. Winchester power point, 60 gr. Nosler partition and 64 gr. Nosler bonded performance.