The new RRA .17 HMR that we're reviewing today is Rock River Arms' first AR-platform rifle chambered in .17 HMR. If you're a fan of rimfire guns, or just looking for an accurate and reliable varminter, this semi-auto makes the most of the .17 HMR's ballistic range.
" What really gets interesting is what's inside of this gun and how this gun works," remarks American Rifleman's Chris Olsen. "So with a Rock River RRA .17 HMR, you get a pretty unique gas system. It is gas operated, but it's also delayed blowback. So you get that direct impingement like you get on a standard AR where gas is going rearward, but there's a ball detent mounted inside of the upper receiver that is designed to hold the bolt just temporarily to reduce some of the pressure in the barrel before clearing it and going rearward."
What that unique gas system does is allow for reliable cycling in the .17 HMR chambering in bullet weights from 15.5- to 20-gr. Accuracy is maximized with a precision-manufactured 41V50 CMV 18" barrel rifled with a 1:9 twist. Adding to the precision barrel is RRA’s NM Ultra Match 2-stage trigger—a key ingredient for pinpoint accuracy. The rifle uses a rear charging handle, and even comes with a winter trigger guard for use when wearing gloves.
The RRA .17 HMR was also created for adaptability and customization. With an ergonomic Magpul MOE grip, adjustable Magpul MOE SL-K six-position stock, and RRA’s lightweight 15" free-float handguard with M-LOK compatibility, the RRA .17HMR is ready to be outfitted with essential accessories like a bipod, lights, thermal, and optic. A 10-round magazine is included. MSRP $1,300; RockRiverArms.com.
