Does anyone have experience with the Rock River Arms uppers. I was looking to purchase an RRA Varmint 24" Standard upper. What I liked besides the cost ($520) was the fact that the barrel diameter is .920 in front of the gas block and a full 1.050 under the handguard. Also come with the complete bolt carrier group and charging handle assembly and the stud for a bipod. The barrel also come with either a 1:8 twist or 1:12 twist. My Remington 700 Varmint has a 1:12 twist and shoots very very good at 200 yards using standard 223 Black Hills 55 grain ammo. May stick to that same twist. My lower is an Olympic Arms PCR. Would of gone with the olympic upper but the cost is $800 dollars for the same thing as the RRA. I do not feel that its worth $300 dollars more for the Olympic's upper. Any comments would be much appreciated.