A Bigger Stick: We Test AR-15s In 6.8 SPC from BRC and LWRCI
The intermediate chambering of the Stoner mechanism adds power to the 5.56’s basic performance, but the BR4 Odin and the M6A2 are two versions of it we probably wouldn’t buy.
Throughout American history, citizens have adopted the military arms of the nation for civilian use. Today, the military-based semi-auto AR-15 platform is showing the genius of Eugene Stoner by being adopted for a multitude of uses, in particular as a hunting round for medium-sized big game. One cartridge particularly suited to this role is Remington’s 6.8 SPC, an intermediate cartridge originally developed by the U.S. Army’s Marksmanship Unit and Special Forces personnel to provide more power and penetration than the standard 5.56 NATO round, while maintaining compatibility with the AR-15 platform. The 6.8 SPC round, topped with appropriate hunting bullets, is currently being used in the field to harvest deer, hogs, and other large game. Thus, our interest in testing two very different rifles chambered in this cartridge, the LWRCI M6A2 and the Battle Rifle Company M4 Odin.
The 6.8 SPC is a cartridge that pushes the performance envelope for the AR-15 platform. Over time, there have been several specifications published for the chamber, with a great deal of discussion regarding the compatibility between the different specifications. However, the available data shows the differences between chamber specs are minimal, so compatibility should not be a problem. It’s worth noting, though, that one ammunition brand in this test, Silver State Armory, suffered two case ruptures. As there was one rupture in each rifle, and both failures were early in the testing cycle, we are inclined to think the issue was with the ammunition and not the rifles’ designs or cleanliness. Having two ruptures in one test does not inspire confidence in the ammunition, so we wanted to mention that immediately.
LWRCI is headquartered in Cambridge, Maryland. The company says its mission is to provide “durable tools for the warfighter and law enforcement officer.” According to the company’s website, LWRC International (LWRCI) “was founded to pursue the development of a short-stroke gas-piston-operated version of the AR-15/M16/M4 family of weapons.” The company says it focused on eliminating the inherent shortcomings in the direct-impingement operating system, resulting in the family of M6 rifles and carbines.
The LWRC International M6 series rifles are rotary-bolt, magazine-fed, air-cooled, self-loading designs chambered in 5.56x45mm NATO and 6.8x43mm SPC. Some of the more common variations include the M6SL, a lightweight mid-length unit with polymer handguards; the M6A1, which has an A-frame front sight and quad-rail handguards; the M6A3, which has a four-position gas block, a mid-length action, and a mid-length quad rail; and the M6-SPR, which has a low-profile gas block and SPR configurable rail system. Our test unit was the M6A2 version, which has a low-profile gas block with a mid-length quad rail and heavy-duty polymer rail covers. The M6A2 retains about an 80% parts commonality with the direct-impingement carbine.
Battle Rifle Company was started in April 2010 and is based in Houston. The receiver on our rifle was stamped Seabrook, Texas. The company sells direct to the consumer or through its dealer network. The BR4 Odin gets part of its name from the Odin Works 12.5-inch keymod rail, which keeps weight down while allowing many accessory configurations. The BR4 designation is what the manufacturer gives all its guns with a 16-inch or shorter barrels. The 14.5-inch barrel has a Battle Rifle flash suppressor mounted permanently. The gun comes with a soft zippered case and one 25-round magazine. This was a direct-gas-impingement action, so it allowed us to compare it head to head with the piston gun for cleanliness, coolness, and function.