If you plan on shooting heavy-for-caliber bullets, like the 69 grain bullets then get the rifle with the 1x9 twist. If you plan to shoot most of the factory stuff in 45, 50, and 55 grain bullets, then the 1x12 twist is what you need. You need to ask yourself what you plan to use the rifle for, target work up to say 300 yards, hunting p-dogs and coyots out to 300 yards or so, then the 50 grain bullets will be your ticket. If you plan on any long range .22 caliber target work and shooting, then go with the heavier .224 caliber bullets. I have a 1x12 twist in my CZ 527 Lux/American. That is one, very accurate rifle. Tom Purdom