Rock River Arms LAR-BT3 Operator DMR Enhanced

Rock River Arms LAR-BT3 Operator DMR Enhanced

By: Guy Coursey

Rugged, reliable, and hearing-safe from the factory

Back in the early 2000s, Rock River Arms was part of a small contingent of top-quality AR manufacturers often referred to as the “Big Three”, alongside Colt and Bushmaster. Obviously, the competition has grown tremendously in the past twenty years, but one thing has held true — Rock River Arms (RRA) still needs to be on the tip of your tongue when you think of manufacturers of quality AR-type rifles. RRA makes as many or more variations as most other producers, and they still compete with the best on a performance level. The latest examples of RRAs prolific offerings are its new Operator Designated Marksman Rifle (DMR) series, which consists of six different models, or a family, as I like to think of them. Our focus today is on the OP1007BT Enhanced model, a .308/7.62 NATO caliber, 20-inch barreled AR-10 style semi-auto rifle. Its smaller brother, OP1012BT, has a 16-inch barrel, with both sizes coming with a Silencer Co. 300 Chimera suppressor (requiring the usual nonsensical paperwork and wait from everyone’s favorite three-letter federal agency). Both versions are also offered with an A2 muzzle device and no suppressor for those who don’t have that kind of patience or money. RRA also has two .223/5.56 NATO DMR models with 20 and 16-inch barrels, both with mostly similar parts and characteristics to their higher caliber cousins.

The 7.62mm Operator DMR is available with a SilencerCo Chimera 300 suppressor directly from the factory, attached to either a 16 or 20-inch (tested) barrel. Suppressor-equipped models come with a SilencerCo ASR suppressor mount/muzzle brake; otherwise, it’s an A2 birdcage flash hider. A 17-inch M-LOK/Picatinny handguard is accompanied by two M-LOK Picatinny strips and an M-LOK QD sling cup. Magpul MBUS Pro sights are standard.

RRA has had a long line of excellent AR-15 rifles for decades but is now entering a blooming market for specialized DMRs. For those who may still be unaware of the DMR pedigree, recall that following 9/11/2001, during the opening decades of the 21st Century, the U.S. military experienced consistent ground combat in Iraq, Afghanistan, and other sub-second world countries around the planet. During this Global War On Terror or GWOT, some interesting lessons were learned (or re-learned) on both sides. One of those lessons was that there was a gap in the effective range of our issued infantry rifles, the M16/M4, and the longer ranges where specially trained snipers operated. Our enemies learned to exploit this, so in the interim, Uncle Sam pulled some 7.62mm NATO M14s out of mothballs and mounted scopes. Soon, more purpose-built rifles, such as the Knights Armament SR25, were being built, and infantrymen trained to operate them. The DMR operator is a trained marksman who provides overwatch, effective fire suppression, and accurate mid-range (300-800 yards) engagements for his unit while maneuvering against the enemy. The DMR rifle itself is usually an upgraded version of the standard semi-auto infantry rifle, commonly in .308/7.62 NATO caliber, and typically mounts a low-power variable optic to increase range and lethality potential. As of today, the choices of AR-10 pattern, DMR-type rifles out there for military and civilian use is large and varied.

The Operator DMR’s billet upper and lower receivers are treated to attractive-looking recessed cuts on the milling machine, and the same pattern on the bolt release paddle ties in nicely. As with most of its offerings, RRA equips this rifle with its Star Safety Selector; its single raised point completely eliminates binding when swinging back and forth between safe and fire.

The 20” barreled OP1007BT Operator DMR rifle I was sent (less the suppressor for NFA reasons) for testing has all the parts and characteristics one would expect from a modern, well-made DMR. The receivers are RRAs billet LAR-BT3 units, which are both stout and

The rifle’s enlarged integral trigger guard contains RRA’s Two-Stage Ultra Match trigger. The lower receiver features a concave magazine well cut for more efficient mag insertion and release of its metal 20-round magazine, of which one is included.

feature recesses and scallops, which are mostly cosmetic but are attractive. The lower has a concave magazine well for more efficient mag insertion and release, as well as RRAs proprietary Star safety selector and an RRA branded Hogue rubber-overmolded grip. The trigger is RRAs Ultra Match two-stage trigger, and the stock is a BCM 6-position SOPMOD. The upper has a 17-inch free-floating rail with a full-length strip of Picatinny rail on top, and M-LOK cuts at 3, 6, and 9 o’clock for mounting whatever accessories are necessary. The rifle’s lightweight, 20-inch chrome-lined barrel has a mid-length gas system and is equipped with A SilencerCo Charlie ASR three-port muzzle brake to accept the included Chimera 300 suppressor. A set of Magpul Pro flip-up MBUS iron sights are included, as are an RRA AR-10 style BT-3 metal 20-round magazine, two M-LOK Picatinny rails, a QD sling mount, a padded hard case, and the usual manuals. In addition, my rifle came with a Trijicon Tenmile 4.5-30×56 long-range rifle scope in a Larue SPR 1.5 QD mount. Space prevents extensive discussion of this optic, but suffice it to say, it’s all one would expect from Trijicon: uber-clear glass, excellent controls, and a user-friendly reticle. It is also heavy, adding about two pounds to the 10 or so the Operator already weighs, and in truth, probably more scope than the average DMR would likely wear. That said, more scope is usually better than less.

Out back, you’ll find a solid combination of a six-position BCM MOD-0 SOPMOD buttstock with a pronounced sloped cheekweld and a Hogue rubber-overmold beavertail pistol grip.

My range time with the Operator went generally as expected, if not entirely as hoped. A combination of scheduling, weather, and range limitations prevented the exhaustive testing I would have preferred with the Operator. I managed to get about only 100 or so rounds in with four types of .308 and 7.62mm brands of ammo, but Editor Ben Battles squeezed

The Operator DMR’s accuracy potential proved impressive, with some very tight clusters within the five-shot groups during 100-yard bench testing—made even more impressive without match-grade ammunition on hand.

in another 200-plus rounds out of the rifle after the fact, with no recorded function issues. After getting on paper with some bargain CBC 147gr ball, I shot five-shot groups with my other three brands at 100 yards, firing from a bench rest. The sun angle was not optimal, being low and just to my front right at that time of day, and I found myself wishing I had brought my bipod so I could shoot from prone. In addition, the Ultra Match trigger was adequate but not as light as I would have preferred, breaking at about 4.25 pounds. Nevertheless, personal gripes and excuses aside, I still achieved the anticipated results. RRA advertises the non-suppressed versions of the Operator DMR will hold one MOA at 100 yards, with 1.5 MOA for the suppressed versions. It proved to be so for me, with strong potential for better. My groups averaged between 1.5-2 inches, with the best five-shot group being 1-1/4 inch, somewhat surprisingly, with PMC .308 147gr FMJ-BT. Of note, a slightly larger group was achieved using Hornady .308 150gr Interlock, but with the best four being inside 0.6 inches. As important, functionality of my Operator was near flawless throughout testing, with only one failure to feed using both the BT3 mag and a 20-round Magpul LR/SR PMAG. Overall, very satisfactory.

Durable, precise, and crystal clear, the Trijicon Tenmile 4.5-30×56 is fast becoming a staff favorite for mid- to long-range precision rifle engagements. Between the large 34mm tube and 56mm objective, light transmission is outstanding. Custom-built turrets are available, as are either an MOA or MRAD reticle mounted in either the FFP or SFP. Check out the details at

In today’s competitive DMR market, RRA is on the board with its Operator series. If you are looking for a quality semi-precision gas gun for duty or defense applications that comes with everything necessary out of the box minus a magnifying optic, the Operator is a worthy candidate. The .308/7.62 NATO versions can be had for an MSRP from $1,935 to $1,960 for the non-suppressed versions or $3,070 to $3100 equipped with the SilencerCo Chimera 300 suppressor. Check them out at your nearest dealer, or for more information, contact Rock River Arms; Tel.: (866) 980-7625; E-mail: [email protected]; Web:


MSRP:                        $1,935 to $3,100

Caliber:                      .308 Win./7.62 NATO

Barrel Length:            16 to 20 inches

Weight:                      8.30 to 10.40 lbs.

Gas System:              Mid Length

Furniture:                   BCM Stock/Hogue Handgrip

Sights:                       Magpul MBUS Pro

Trigger:                      RRA Two-Stage Ultra Match

Mag Capacity:            20

Quiet, precise, and reliable sum up the Chimera-equipped Operator DMR. This rifle does everything it’s supposed to do and is backed by one of the oldest names in the AR business. If you’re currently in the market for this type of platform, we can wholeheartedly recommend RRA’s version.