I've got a 12.5" (Noveske barrel) on my AR10 SBR. It runs fine....even with the suppressor. She's not as "loud" as you would think she would be (running an AAC brakeout comp). As far as accuracy, she'll drill the center of a target. Now keep in mind, that I'm not looking for any kind of MOA with her. She's made for kicking in doors or shooting through them......not sniping.
Just recently, while playing at 50 yards. She ate the s h i t out of the center of the target. Same at 100. Still, not one hole or cloverleaf type of accuracy. BUT, if it was human.......it wouldn't be anymore.