Personally I'd opt for a 24" to 26" bbl. just because I'd rather have more than I need than less. I've got 2, 26" .223's with 12 & 9 twists & .223AI with 8 twist. This way I can maximize performance for the wide range of bullets now available for .223 Rem. as well as, extend accuracy range with my .223AI and heavies. 600 yd PD hits are not uncommon with the AI. Just another angle to consider. Good luck with your buy :)