Iv'e been saving my pennies, nickels & dimes for a nice Varmint upper for my AR. I'm eyeballing the Rock River models, and have a question regarding barrel twists. My first choice was a 20" 1/8, but then I noticed that they have a 24" barrel available with a 1/12. My primary use will be target shooting, with the occasional prairie dog/coyote hunt. Several years back I had a Win 70 Varmint model, and I used a LOT of 50 and 55 grain SX bullets with very fine accuracy and performance. I won't be shooting any 600 yard matches with this, so I'm leaning towards the 1/12 twist and lighter bullets. Am I on the right track here? Just wanting to hear other opinions...Thanks.