I just finished a .223 Imp build on a Stevens 200 action. I used a CBI barrel in 1:9 twist. I haven't shot anything heavier than 69Gr in it so I can't help with that question, but it is much more accurate than I am able to shoot. I'm still working on load development for it and it shoots 0.5 inch 5 shot groups @ 100 with me pulling shots to ruin otherwise 0.3 or smaller groups. Here is my rifle and some groups that I have shot so far.

http://savageshooters.com/SavageForu...c,43632.0.html