Few would argue that the AR-15 has become one of the most relevant rifle designs available today. There are many reasons it has become so popular. Generations of riflemen are familiar with its upkeep and operation, thanks to the fact that the platform has been in military service for more than 50 years. It requires no special tools to disassemble and maintain. The rifle’s ergonomics make it comfortable to shoot, even during prolonged range sessions, and there’s no end to the number of aftermarket items available for those desiring to customize it.
While AR-pattern rifles are extremely popular, they have reached a plateau where most new developments result in a negligible increase in quantifiable performance. Until recently, that is. Efforts by LWRCI, Magpul and ATK now provide the venerable Stoner design with its first significant performance increase in decades.
Each of the three companies tackled a crucial portion of the AR’s performance upgrade. LWRCI did some heavy lifting by redesigning the rifle to accommodate a cartridge offering more ballistic performance than the traditional 5.56 chambering. The round the company chose for its new rifle was 6.8 SPC. Optimizing the AR for a cartridge that falls between the 5.56 and 7.62 NATO is no small task. It called for taking the relatively small and light AR-15 platform and stuffing the larger 6.8 SPC round into it. And that’s just what LWRCI did.
Refining a Concept
LWRCI isn’t the first manufacturer to chamber an AR-15 pattern rifle to 6.8 SPC. Since the round’s introduction in 2004, several manufacturers have done so. The problem with maintaining the standard specifications for the AR-15 while chambering the rifle in 6.8 SPC is that the larger cartridge doesn’t want to fit through the 5.56×45-size mag well, nor does it particuarly like getting stuffed into magazines designed almost 50 years before the 6.8 was conceived.
The obvious step toward solving the problem is to enlarge the mag well and make a bigger magazine to put in it. LWRCI took the very sensible approach of looking at the AR-15 bolt carrier and determining how far they could enlarge the mag well without having to redesign the bolt carrier. That’s a smart move. Since the bolt carrier works just fine, it’s best to leave it alone. Once they enlarged the magazine well, they also added a small shelf inside the front of the mag well to prevent “overinsertion” of the magazine. This little feature ensures that no problems will arise should the shooter decide to use the rifle’s magazine as a rest to steady the rifle.
The new LWRCI M6.8-A5 also has a fully ambidextrous lower receiver that makes it possible to manipulate the rifle with minimal gun juggling. With traditional AR-15s, the shooter has to remove his firing hand from the pistol grip to pull the charging handle to the rear so that the support hand can manipulate the bolt catch and lock the bolt to the rear. This is the first maneuver for doing everything from loading and unloading the rifle to clearing malfunctions, so it gets repeated often.
With LWRCI’s new ambidextrous design, the firing hand can stay on the pistol grip while it manipulates the bolt catch, and the support hand pulls the charging handle to the rear. This small change to the rifle’s manual of arms might not sound like much, but it eliminates the most time-consuming step of switching hands around. Seconds might not matter to many shooters, but to citizens defending their homes, soldiers or law enforcement professionals, a few seconds can determine whether we live or die. There’s also the added convenience of having a rifle that both right- and left-handed shooters can easily manipulate.
The upper receiver saw some slight changes, too. The portion of it that mates against the lower receiver had to be opened up to accommodate the larger magazine. The upper also saw the addition of one of the sweetest ambidextrous charging handles I’ve seen on an AR. It’s unobtrusive yet still offers plenty of purchase. The way that the retaining arm rotates away from the charging handle shaft toward the perpendicular handle indicates that there is very little outward pressure placed on the pin about which the retaining arm rotates. When charging handles break, it’s usually because this pin gives way from outward pressure. I’m not sure you could break the LWRCI charging handle through normal manipulation if you made it a point to try.
The rest of the six-eight is classic LWRCI. It’s a piston-operated Stoner variation that’s been updated with all of the latest coatings and materials available to further refine the design. LWRCI has been making piston rifles for quite a while, and the company’s brain trust has long since figured out how to fabricate a premium product. The hammer-forged barrels are surface-converted with NiCorr, making the finish incredibly hard and durable, much more so than their chrome-lined and Parkerized competitors. The piston system self-regulates, so there are no wild variations in bolt speed (as is often the case with the traditional direct-gas-impingement system, especially when using a suppressor). The bolt carrier and bolt are coated with nickel boron, making them extremely slick and less dependent on lubrication for reliable operation.
LWRCI also takes the time to make its bolts out of 9310 steel, not the traditional Carpenter 158 or less expensive 8620 that are often used in other ARs. The 9310 steel has a little more nickel than the other two, making it less brittle and longer-lasting. No single part takes more of a beating in an AR than the bolt, so it’s important to have as stout a one as possible. I prefer that my bolts be made from 9310 even though they’re more expensive (and are standard in all LWRCI rifles).
Part of the AR-15’s popularity comes from the inexpensive 30-round magazines that feed the rifle. Many of us remember the 1994–2004 magazine ban and like to keep plenty of magazines around for our ARs. This has been no problem for those whose rifles are chambered in 5.56, but it has been hugely problematic for those with rifles chambered in 6.8 SPC. Up until Magpul’s intervention, the only viable choices for 6.8 SPC magazines were Barret and PRI. These magazines cost approximately $40 each, so keeping several on hand quickly became an expensive proposition.
As part of a joint venture with LWRCI, Magpul designed a new version of its popular PMAG to fit the newer, larger magazine well. While the COL of the 6.8 SPC is 21/4 inches, the new PMAG offers 2.32 inches of internal volume. This enables bullet manufacturers — and reloaders — to use longer bullets with better ballistic coefficients, further stretching the effective range of the cartridge.
The 6.8 SPC PMAG accepts 30 rounds and fits snugly in the magazine well. It is approximately half an inch taller and one-tenth of an inch wider than its 5.56 stablemate. And it fits just fine in magazine pouches designed for the 5.56 mags.
…And New Ammo
ATK also participated in the project by developing a few new loads for the 6.8 SPC. In an effort to drive down the cost of 6.8 SPC to make it more competitive with the 5.56, ATK has devoted an entire production line to loading 6.8 SPC. Assuming the economy-of-scale principle applies, this will result in a significant price decrease. Current retail pricing for the new ammunition still hovers at around $1 a round, but I expect that price to drop once the new line generates some inventory.
The two new ATK products supporting the 6.8 SPC are an American Eagle loading with a 115-grain FMJ and a Fusion load with another 115-grain bullet. The American Eagle ammo should be great for range use, and the Fusion load with its expanding bullet should be ideal for hunting and self-defense.
Shooting LWRCI’s new rifle was a pleasant experience. I’m sure the 6.8 SPC recoils more than a 5.56 carbine, but neither generates enough backthrust to ever be uncomfortable. The rifle I evaluated is one of the first ones produced, so I anticipated a minor problem or two.
That was not the case. The rifle functioned flawlessly. I was able to shoot two different Hornady loads through the rifle. Five-shot groups for the 110-grain Hornady Tap averaged 1.7 inches, with the best group measuring 11/2 inches. The Hornady 110-grain BTHP load would consistently put three shots into one to 1.3 inches, then the next two rounds would open up the group to right around two inches.
My Oehler 35P had the TAP load moving at 2,567 fps out of the 16-inch barrel. The 110-grain BTHP had a muzzle velocity of 2,393 fps.
What LWRCI, Magpul and ATK have done is take an AR-15-pattern rifle and bump its combat-effective range from 200 meters to 400 meters. This change is possible thanks to the 6.8 SPC chambering. Along the way they’ve addressed the problem of expensive and heavy magazines and costly ammunition. The efforts of these three companies has breathed new life into the 6.8 SPC.