My .22 BR has a 12" twist and shoots 40 gr V-Max's and Ballistic Tips to over 4200 fps giving groups in the 4's (0.4" for five shots), and 50's at 3800 fps with equivalent accuracy. Bad news for prairie dogs! The fast twist didn't help with 60 and 65 gr flatbase bullets (Berger's) though because they didn't shoot as well as lighter bullets for some reason.