mine as stated is 24" I went with rifle length w/adjustable gas block. on the 243 as stated I went with h/p bolt. that said I just put together a 260 rem. and went with std 308 bolt. as far as twist, what are you going to do with it. a 243 in the lighter bullets is quite capable of over rotating them with std 1:10 twist, heavy bullets of coarse need more twist