I would love a 12 twist, it's the 14 twists that suck. My buddies and I want AR15s for coyote hunting-40, 50 and 53 grain bullets. A 12 twist would be perfect for that. An 8 twist just over spins the bullets and you give up a little velocity, a little accuracy and a lot of bullet integrity.
I shoot coyotes with several guns but my main gun is a Kimber Montana I had rebarreled to 22-250AI in an 8 twist. I started out shooting 55 gr NBT's and it shoots them just fine. No jacket issues, coyote dies just as dead and I've even killed bobcats with it that didn't explode. I haven't tried any lighter bullets in it and in fact went to 75 gr A Max's but I've killed many a critter with a 40 Gr NBT in my 1/7 223's as well as a couple of 1/8's. I just haven't seen any downside to a 1/8 at all.
