Rock River Arms (RRA) was founded by Chuck and Mark Larson in 1996. This American manufacturing company quickly developed a reputation for quality AR-15 carbines that led to a contract with the Drug Enforcement Administration in 2003. Over the years, its product lines have expanded to include AR-10-pattern platforms, bolt-action rifles and in-house custom M1911 pistols. In 2019, RRA diversified its AR-15 catalog once again by adding the LAR-22 series of dedicated rimfire carbines chambered in .22 Long Rifle. As of this writing, the available models include three versions of the Tactical Carbine, a pair of Mid A4 options, the NM A4 and the NM A4 CMP Trainer. This evaluation takes a closer look at the version of the Tactical Carbine outfitted with aluminum upper and lower receivers and a non-folding, length-adjustable stock.
Unlike some semi-automatic rifles that only emulate the cosmetics of an AR, the LAR-22 is an AR-15 that happens to be chambered in .22 LR. The majority of this rifle’s components are the same mil-spec parts used by RRA to build its 5.56 NATO/.223 Rem. centerfire models. These include the muzzle device, handguard and the entirety of the lower receiver assembly. Key changes have been made to the upper assembly, however, to accommodate the diminutive .22 LR cartridge; the barrel, upper receiver, bolt assembly, charging handle and recoil assembly are all specialized rimfire parts. A dedicated magazine is also required. The complete .22 LR upper receiver and magazine are drop-in-compatible with most mil-spec AR-15 lowers with no modifications required.
The LAR-22’s blowback-operated bolt and recoil-spring assembly is fully contained within the upper receiver. Elegant in its execution, the flat-faced bolt is attached to a rearward weight via a top-mounted guide rod wrapped in a single round-wire spring. The rod is pinned at both ends so that the assembly can be removed from the receiver as a unit for routine cleaning. Although the charging handle’s exterior shape is a familiar mil-spec profile, the internal extension has been modified to better fit the rimfire bolt assembly. The flat-top forged-aluminum upper receiver features an integral Picatinny optic rail and is clearly marked “.22 LR” over its ejection port in white lettering. The port is fitted with a cover but the receiver’s forward-assist button has been omitted.
The carbine’s 16″ chromoly-steel barrel has six-groove rifling cut at a 1:16″ twist rate. The 1/2×28 TPI threaded muzzle is fitted with an A2 flash hider at the factory. The vented 3G free-float aluminum handguard is 15″ long; it is topped with a Picatinny rail at the front and rear, but the majority of the top edge is left smooth. M-Lok accessory slots are situated along the right, left and bottom sides along with a total of four QD sling ports, two at the front and two at the rear.
The rifle makes use of a LAR-15M multi-caliber lower receiver, a .22 Long Rifle-specific upper and features many mil-spec parts.
This rifle makes use of RRA’s LAR-15M multi-caliber lower receiver, which is made from forged 7075-T6 aluminum with a hardcoat-anodized finish. The magazine-release button, bolt catch and left-side safety selector are all in their customary locations. Our test rifle came with an oversize winter trigger guard for use with gloved hands. The fire-control group has been upgraded to include RRA’s two-stage trigger. It exhibited a short, clean take-up with a firm stop before breaking smoothly at 4 lbs., 3 ozs., of pressure. The factory-installed polymer pistol grip is of the basic A2 variety.
Although an AR buffer and buffer-spring assembly are not required for this rifle’s action, RRA kept things simple and flexible by installing an aluminum, six-position, commercial buffer tube using a mil-spec latch plate and castle nut. The adjustable shoulder stock features bilateral QD sling ports and a textured rubber buttpad.
The translucent polymer magazine provided with the rifle has a profile that mirrors the 30-round .223 Rem. magazine; this makes it compatible with AR-15 magazine carriers and pouches. They are produced for RRA by Black Dog Machine and can hold up to 25 rounds of ammunition. It should be noted that rimfire magazines made for other .22 LR AR-pattern platforms are not compatible with this rifle due to the differences in their followers. This evaluation was conducted using a total of four factory magazines, all of which operated properly.
At the range, the LAR-22 was test-fired using a Bushnell Rimfire 3-9X 40 mm riflescope. Test ammunition included a range of loads, from practice- to premium-grade; these rounds were topped with 36-grain to 40-grain bullets with listed velocities between 1,200 and 1,470 f.p.s. Throughout testing there were two faulty cartridges, both of which were bulk-box loads and can likely be attributed to inconsistent distribution of primer compound within their rims. Otherwise, this carbine fed, fired and ejected all the ammunition used without any other malfunctions or issues.
The RRA LAR-22 is a well-made and reliable multi-purpose rimfire carbine. Its primary function is to provide the means of practicing with an authentic AR platform using affordably priced .22 LR rimfire ammunition. But cutting ammunition costs is just one role it can fill; rimfire fans will find this to be a handy target-shooting and small-game-hunting model as well. It is also an ideal trainer for instructing new shooters using a less concussive, reduced-recoil rifle.
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