December 07, 2021
Rock River’s time-proven LAR-15 platform is unquestionably reliable. It shoots straight, and is the cat’s pajamas to accessorize. What’s not to like? Almost nothing.
Exception: The AR-15, although not especially heavy, is a bulky firearm — even in carbine form with the stock collapsed. Hence, we have the AR pistol. Essentially, the action is the same, but AR pistols feature a handgun-length barrel. In pistol form, such a firearm is capable of one — or two — hand operation, typically with a padded buffer tube or compact arm brace for stabilization.
Neither accuracy nor velocity match what you can wring out of a full-size platform at distance, but the AR pistol is handier for carry in vehicles, boats or backpacks. Due to the cartridge, they can offer significantly more capability than the typical pistol-caliber handgun.
The AR pistol is not a short-barreled rifle (SBR). It is manufactured and sold as a handgun, which means that it has to have a barrel measuring less than 16 inches. To be classified as a handgun, it cannot have a traditional stock or a vertical handgrip on the forend, but it can have the clever arm brace for one-handed use. Although short and targeted by controversy, it was still legal to accurately fire from the shoulder at the time of this article’s writing. (The Biden Administration seeks to ban stabilizing arm braces.)
Pistols accepting AR-15 magazines go back to the Bushmaster Arm Pistol, which was in production from 1972 to 1988. Olympic Arms continued this legacy with its OA-93, OA-96 and OA-98 models. After the 2004 sunset of the Assault Weapons Ban, AR pistols developed rapidly and have become popular. Rock River Arms offers its version with a twist near and dear to my heart: the new LAR-15 pistol is available in both right- and left-hand configurations.
Left-eject ARs are uncommon; there are only a handful sold across the market. You, undoubtedly of the oppressive right-hand majority might say, “What’s the deal? Operation is ambidextrous!” Obviously, you’ve never fired a right-hand-eject AR from your left shoulder and had red-hot brass cascade down your shirt collar. From a safety standpoint, lefties are better off with left-hand actions because, in case of a catastrophic failure, hot gases and shrapnel are directed away from your face.
Interestingly, most “southpaw” ARs are left-hand eject, but not mirror-image because the safety and bolt release remain on the left side. There are two schools of thought on this: Left-hand eject solves both the safety and hot brass issue, but controls remain in the familiar position. Uniquely, Rock River’s LEF-T LAR-15s, both rifles and pistols, are true left-hand ARs. The safety is on the right, accessible by the thumb of the left (shooting) hand, the bolt catch is on the right, and charging handle release is left-hand. The magazine release is ambidextrous, too.
Most lefties have not seen these features together. They can take a bit of getting used to, but you’re gonna like them! When I took the LAR-15LH out of the factory hard case, all of this was quite familiar: A lefty Rock River AR in 5.56mm has long been my “ranch rifle” on the Kansas farm. When I’m there, it stays handy. It has accounted for several whitetails, and I’ve taken it on several prairie dog shoots.
That Rock River left-handed AR is a known commodity to me. It produces sub-MOA groups on command. Unknown, however, was how the new pistol version would stack up against its big brother for only having a 101/2-inch barrel. The short answer was extremely well!
We must be reasonable though. Any AR pistol with a short barrel is not a full-length AR. Let’s examine its sights, functioning, accuracy, velocity and, finally, handling.
The Rock River LAR-15LH pistol was supplied without sights, but it does have a Picatinny rail that continues along the top of the 91/4-inch, mid-length aluminum handguard. The free-float handguard is M-Lok compatible, so it can be accessorized in the same way as a full-size AR-15. The top rail allows the full range of sights, including flip-up sights, red dots and magnified scopes. With the arm brace supported for shoulder-firing, conventional riflescopes can also be accommodated — just ensure plenty of eye relief!
Decisions on configuration depend on your purposes and needs for employment. With a short barrel and arm brace, I figure the LAR-15 pistol is primarily a close- to medium-range platform. I used this opportunity to evaluate Leupold’s new Freedom RDS ($300, leupold.com). This affordable sight has no magnification, a 1-MOA red dot, and eight illumination settings. It has unlimited eye relief, which is critical for using in the LAR-15 pistol in handgun-type firing positions.
I put the RDS well forward on the rail with Leupold’s supplied cantilever mount. Unlike many red dots, the Freedom has precise quarter-MOA adjustments. This made it easy to get the LAR-15 pistol zeroed at 50 yards, and my Kansas neighbors had fun ringing steel out to 200 yards afterward.
Out of curiosity, and to satisfy G&A’s 100-yard-group protocol, I cheated! For shooting groups, I switched out the RDS for the Leupold VX-6 2-12x42mm that’s been residing on another Rock River LAR-15 rifle.
At The Range
I suppose I’ve put at least 2,000 rounds through that Rock River rifle. I can’t say that I’ve never had a stoppage, but it has been absolutely reliable. We put at least 300 rounds through the new LAR-15LH pistol, and there was never a single jam. Ammunition was largely odds and ends, from 40 to 70 grains, with never a stutter or a hiccup when fed from a variety of commercial and GI-style 20- and 30-round magazines.
The action is still akin to a standard AR-15: direct-impingement, gas operated, rotating bolt and magazine fed. The difference is in the upper receiver, which features a left-hand ejection port, forward assist and brass deflector. Inside, the LEF-T bolt carrier group (BCG) is reversed in design, aside from the firing pin, retaining pins, bolt cam, and gas key. Additionally, Rock River has chromed the BCG for increased wear resistance.
Barrels that are short and stiff tend to be accurate. With handguns, it’s really more a matter of position and sighting equipment that create limitations. When shooting groups for score, I did everything possible to allow the pistol to shoot its best: I used the big VX-6 2-12X scope (of proven accuracy), and I fired from a steady bench over a Caldwell Lead Sled. I also took my time and allowed the barrel to cool between groups and frequent cleaning.
Rock River’s literature states “one MOA” accuracy. This pistol met that criteria with some individual groups, however, as the chart indicates, the averages weren’t there. Honestly, I didn’t expect them to be. That would be asking a lot.
Accuracy was beyond adequate for this firearm’s purposes out to 100 yards. Any perceived shortfalls in accuracy should be attributed to ammunition pairing, both in bullet weights for its twist and the use of rifle-spec loads.
The LAR-15LH has a chrome-moly barrel with a 1:9-inch twist rate. That’s a versatile twist that is able to stabilize a range of bullet weights. In my experience, it’s just a tad slow for the heaviest .224-inch bullets such as 69 grains and above. My Rock River rifle with the same twist is deadly accurate with bullets up to 62 grains, but accuracy falls apart with heavier bullets. Adding to the complexity of this test, shooting for this article was done during pandemic shortages. Initially, I started with one 69-grain load and two different 70-grain loads. Of these, Black Hills’ 70-grain GMX load shot the best at 100 yards with a 2¾-inch average.
I set the other two heavy bullet loads aside and dropped down to Hornady’s 55-grain V-Max bullet — and the pistol came to life! This load produced groups that met Rock River’s one-MOA criterion, averaging 1.497 inches.
I wish I could have tested it with a 60- or 62-grain load, but I didn’t have enough cartridges of any load in this weight range, and I wasn’t able to obtain more.
I did have Hornady’s Superformance 53-grain load. Performance was better than with the heavy bullets, but I think it pointed to another characteristic of AR pistols and ammunition used in them.
The challenge is that most 5.56mm and .223 Remington loads are designed for use in rifle-length barrels, so they’re loaded with propellants that will burn completely to provide consistent velocity in barrels of at least 16 inches. There are 5.56mm loads intended for optimum performance in AR pistols and SBRs, but availability is limited. I suspect most of us who own AR pistols will, as I did, use the ammo we have and accept its range limitations.
Mind you, the three loads I chronographed and fired for groups are proven. But the extreme spreads (ES) in velocity were large: 30 feet per second (fps) for the Black Hills’ 70-grain GMX (amazing), but 140 fps for the 55-grain V-Max and 169 fps for the 53-grain Superformance. This actually follows, because the Superformance load is rated at a screaming 3,465 fps in a rifle barrel. It struggles to burn the full powder charge in a 101/2-inch pistol barrel.
Velocity In my experience, there is no definitive rule for velocity loss per inch of barrel. It depends on the cartridge, case design and propellant.
Regardless of bullet and load, your .5.56mm or .223-caliber pistol has neither the range, trajectory, nor energy of the same bullet and load in a rifle-length barrel. Factory-specified velocities of the three loads I chronographed in rifle barrels were: 70-grain GMX, 2,800 fps; 55-grain V-MAX, 3,240 fps; 53-grain V-Max, 3,465 fps. With these loads, velocity losses with the pistol were, respectively: 213 fps, 592 fps and 687 fps. This suggests that the faster the load, the greater the loss. This may not always hold true, but Hornady’s Superformance load is a varmint load, wringing max velocity from the .223 case. It stands to reason it will lose the most velocity from a short barrel — and it does.
Weighing 6.3 pounds unloaded without sights, the AR pistol can be a handful. As a plus, with this weight, recoil is very manageable — but beware the muzzle blast from the short barrel!
Some AR pistols are supplied with a padded buffer tube for a more comfortable chin weld, but the arm brace offers support for one-hand shooting. The brace offers a variety of options for two-hand positions, too. Rock River supplies SB Tactical’s SBA3 arm brace, which is sturdy and simple to use. Tightened on the forearm, the arm brace is surprisingly effective. Most of us, me included, will find the AR pistol heavy for one-hand shooting with any degree of accuracy. Two-hand shooting makes the LAR-15 pistol more accurate and controllable. Use of the arm brace in its extended position for conventional shoulder-firing is steady, however, and does not change its legal definition. The LAR-15 pistol is still a handgun! In use, the new LAR-15LH was reliable, accurate, and a lot of fun to shoot, just like an AR — except a lot shorter.
Rock River LAR-15LH Pistol
- Type: Direct impingement, gas operated, rotating bolt, semiautomatic
- Cartridge: 5.56mm NATO
- Capacity: 30 rds.
- Barrel: 10.5 in.; 1:9-in. twist
- Overall Length: 29.25 in.
- Weight: 6 lbs., 5 oz.
- Arm Brace: SB Tactical SBA3
- Pistol Grip: RRA/Hogue soft overmolded rubber
- Handguard: RRA Lightweight, pistol length, M-LOK
- Finish: Hardcoat anodized (aluminum)
- Trigger: 3 lbs., single stage
- Sights: None
- MSRP: $1,045
- Manufacturer: Rock River Arms; rockriverarms.com; 866-980-7625
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