Experiences in Somalia were confirmed in more recent operations in Iraq and Afghanistan where enemy combatants continue to be shot with standard M855 ball ammunition with wounds that are narrow, “through and through” shots similar to those that might have been inflicted by a .22 Mag. This is less of an issue for law enforcement, which isn’t restricted to “ball” ammunition and can use expanding bullets against the “bad guys,” but even so, bigger is generally considered better and so the 6.8mm is a round that provides an alternative caliber to law enforcement, especially in short-barreled carbines where the 6.8’s ballistics overshadow those of the 5.56mm.
The 6.8mm SPC was fully developed and recommended for adoption by Army Special Forces units by the time the War on Terror began. The 6.8mm SPC was designed to perform in essentially the same role as the 5.56mm, but with enhanced terminal ballistics out to 550 meters. In testing, the 6.8mm surpassed all types of 5.56mm rounds in every area of terminal ballistics at any range from point blank to 500 meters. Because of this, in 2002 it was recommended that the 6.8mm SPC round be adopted as soon as possible as the standard caliber for USSOCOM and some other special warfare organizations. As of early 2008, this has yet to be implemented for reasons that are beyond the scope of this article, but the 6.8mm SPC is superior to the 5.56mm in terms of both terminal ballistics and barrier penetration, key attributes for law enforcement.
Terminal ballistics expert Lt. Cdr Gary Roberts explored the implications of the 6.8mm SPC for law enforcement in depth in March 2004. Once the decision has been made to employ lethal force, law enforcement weapons have only one purpose: to stop dangerous individuals as quickly as possible to prevent them from continuing their threatening activities. According to Roberts’ study, 6.8mm SPC Development and Implications for Law Enforcement: “Bullets…must reliably penetrate a minimum of…10 to 12 inches of tissue in order to ensure disruption of the major organs and blood vessels in the torso from any angle.” In order to achieve this, 5.56mm bullets must yaw, expand significantly or fragment in order to create the permanent wound cavity required to reliably incapacitate violent individuals. Even with expanding rounds available to law enforcement, Lt. Cdr Roberts concluded through extensive testing that after being shot with any 5.56mm bullet, “…vioent suspects can remain a danger to law enforcement personnel and the pubic.”
One thing that we should remember is that the 5.56mm round was originally intended for hunting small game and varmints. In many states it is illegal to hunt deer with a 5.56mm/.223. Considering that many adult deer are approximately the size and weight of a human, the question arises as to just how effective a .223 can be on human targets. To quote again from Lt Cdr Roberts’ in-depth study, “Compared to current 5.56mm carbines, pistol caliber SMGs and small caliber PDWs, the 6.8mm offers law enforcement a cost effective, yet significantly improved capability to rapidly incapacitate and stop dangerous individuals who pose an immediate threat to public safety….” With many law enforcement organizations changing from submachine guns and pistol caliber carbines to M4-type carbines, the ballistic shortcomings noted by the military have come to the attention of American law enforcement.
Although the 6.8mm SPC’s ballistics are demonstrably superior to those of the 5.56mm, the 5.56mm remains a primary law enforcement cartridge because it is widely available and ammunition has been relatively plentiful and inexpensive. Recently, however, 5.56mm ammunition prices have risen and availability has been curtailed as military demand for 5.56mm ammo increased because of operations in the Middle East and elsewhere. Also, 6.8mm ammunition has been a long time coming in quantities needed for law enforcement. Another factor is the lack of weapons to fire the 6.8mm SPC. Until recently, only Barrett Firearms offered 6.8mm SPC carbines, but that has changed as other manufacturers got on board with 6.8mm SPC carbines and rifles. One of the most recent is the Stag Arms 6.8mm SPC carbine. Ammunition is currently available from Hornady, Remington and Silver State, which specializes in manufacturing 6.8mm cartridges.
One of the best features of the 6.8mm is its simple conversion from existing 5.56mm arms. All that is necessary is a replacement upper receiver to include bolt and bolt carrier, since the 6.8mm case head diameter is larger than that of the 5.56mm. The 6.8mm magazines, different internally than those in 5.56mm, are also required. If the user desires, complete rifles and carbines are available from Stag Arms. For our test, we acquired a Stag Arms 6.8mm SPC 16-inch barreled carbine. Each Stag Arms 6.8mm is shipped with two magazines. We should note that 6.8mm SPC magazines are externally the same as 5.56mm magazines and although there have been reports of successful conversions of 5.56mm magazines to 6.8mm SPC by simply changing followers and springs, we don’t recommend such a “band-aid” fix. If you are going to change over to 6.8mm SPC, order dedicated 6.8mm SPC magazines. We recommend at least five per carbine for LE use. The 6.8mm SPC magazines hold 26 to 28 rounds, depending on manufacturer. Also, the 6.8mm magazines can generally be differentiated from 5.56mm magazines by their red followers that are configured differently. But since Murphy is along for the ride at all times, we like to label the floor plate of our 6.8mm magazines “6.8” just to make sure.
The Stag Arms 6.8 comes ready to be fitted with modern tactical accessories right from the box. The optional Vltor collapsible Modstock is a decided improvement over the original M4 type, with improved configuration that provides a cheek rest that is actually better than a full stock AR. The Modstock configures the shooter’s eye relief perfectly for using optics that are virtually universal in today’s tactical operations, both military and law enforcement. Even better, the Modstock provides waterproof compartments for batteries and other small gear. These compartments are not only waterproof, but can be accessed without removing the stock from the drive spring tube, unlike some others that must have the stock removed in order to access the storage compartments. Furthermore, the latest Modstocks have extra compartments near the toe of the butt and a rubber recoil pad that isn’t necessary for recoil with the 6.8mm, but firmly positions the carbine against the shooter’s shoulder for improved fire control.
The Stag 6.8mm also came with a Samson STAR-C Tactical Accessory Rail System that can be installed without removing the front sight, if the user decides to add this accessory to an existing carbine. It also free floats the barrel, a critical element when using heavy accessories and with full-auto fire, although this is less critical in semi-auto. Why is a free-floating barrel so critical when using the many accessories that are common in today’s tactical operations and in full-auto? When Special Operations Forces must break contact or overcome an ambush, they must lay down a heavy volume of full auto-fire that causes barrels to reach red-hot temperatures in very short order, especially in carbines with short 6-inch gas tubes. If the barrel isn’t fully free-floated, heavy pressure on the vertical foregrip can actually cause the red-hot barrel to bend slightly in the center with the result that bullets come out the “side of the barrel” rather than out the muzzle. Not what you want in a firefight. As unlikely as this may sound, it is documented fact, so a free-floating tube does much more than just enhance accuracy. The Samson tube is made of 6061-T6 aircraft aluminum, is hard coat anodized to MILSPEC, has a removable bottom rail to accommodate an M203 Grenade Launcher, a winged clamp to eliminate barrel nut rotation and forms a continuous top rail in conjunction with the carbine’s flat top upper receiver. It is also well ventilated to dissipate heat.
There is a huge array of aftermarket gear available for ARs, and that is another beauty of the Stag Arms weapon; just about any MILSPEC component or accessory that fits an AR can be used in conjunction with the flat top upper and Samson STAR-C free-floating rail system, so existing accessories can be used if the decision is made to convert from 5.56mm carbines.
It is rare to see any tactical carbine without optics and one of the most popular ones in use by the military and law enforcement tactical teams is Trijicon’s ACOG. The military is gradually eliminating iron sights in favor of optics whose technology has brought them to the point where they are nearly as reliable and rugged as iron sights, although every rifle or carbine with optics has backup iron sights, just in case. Optics eliminate the need to align three separate elements necessary with open sights: rear sight, front sight and target. With an optic, all that is necessary is to place the optic’s reticle on the target and shoot it, although the shooter must still correctly estimate range and windage. Even so, optics are much faster “on target” than open sights, especially at CQB distances that characterize urban operations in Iraq and American SWAT operations that generally involve dynamic entries and room/building clearing.
There is a variety of MILSPEC optics available for LE use. The US Marine Corps has chosen Trijicon’s ACOG (Advanced Combat Optical Gunsight) TA31RCO 4x32mm optic. This optic utilizes the Bindon “both eyes open” aiming concept, which provides quick target acquisition at CQB distances while enhancing target identification and hit probability out to 800 meters. Our particular sight was calibrated for the standard 5.56mm round, but since our test was conducted at a fixed distance and 6.8mm ballistics are similar, we chose the military standard Trijicon. The reticle is illuminated via a combination of fiber optic and tritium, allowing the aiming point to be constantly illuminated without batteries. The tritium illuminates the chevron aiming point in complete darkness, while the fiber optic regulates reticle brightness in daylight depending on ambient light conditions. Our test TA31RCO came with a Trijicon TA57 KillFlash anti-reflection device manufactured by Tenebraex Corporation. This device prevents glint from revealing the presence of a shooter whose rifle is equipped with the Trijicon ACOG.
One of the most significant developments in night vision technology is Trijicon’s Gen III+ Tactical Weapon Sight (TaNS), especially designed for short-barreled carbines. Manufactured for Trijicon by Optical Systems Technology, the TaNS is built to full military specification and must be actually used to appreciate its effect on night operations. The Gen 3+ TaNS completely overshadows earlier night vision optics. Images seen through the TaNS in almost total darkness are completely clear with nothing to distract the shooter. Unlike earlier night vision devices, the TaNS mounts forward of the day optic on the Stag Arms MIL-STD-1913 rail via a LaRue throw lever, so eye relief is not an issue. Previous night vision optics like the AN/PVS-14 had to be placed behind the day optic, requiring an adapter and IR illuminated reticle with eye relief issues that made them inconvenient to use. The latest night vision optics like the TaNS can be used with the weapon’s day optics without adapters of any kind. The TaNS offers night vision capabilities almost as sophisticated as the larger AN/PVS-22 in a more compact package.
The TaNS can also be used as a hand-held night vision optic. There is no IR mode on the Trijicon TA31RCO, so the TaNS is almost mandatory for use with short-barreled carbines like our test Stag Arms 6.8mm in night operations. The TaNS has no effect on the day optic’s reticle or the rifle’s zero. Further, the TaNS incorporates autogating technology that automatically regulates the amount of light entering the intensifier tube, preventing “blooming” caused by bright lights and muzzle flashes. Finally, the TaNS intensifier tube is assembled in the optic so that it is “shock mitigated,” meaning that it is resistant to shock. Just because a NVS has a Gen 3 or Gen 3+ tube doesn’t mean that it has autogating and shock mitigation, so beware of imitations.
We also installed The Mako Group’s T-Grip vertical foregrip that adapts to any one-inch diameter high intensity light. This vertical foregrip attaches to any MIL-STD-1913 rail via a quick detach mechanism and firmly clamps any 1-inch light into place. The T-Grip has a trigger to press in on the rear tailcap switch present on most such lights. For this application, we chose a Laser Devices OP-6 “Operator” 5-watt LED light. This little light is incredibly rugged, with shock-absorbing light head and conforms to MIL-STD-810F for rugged environmental conditions. The OP-6 is machined from aircraft aluminum, is waterproof to 20 meters and its LED version has an output of an incredible 150 lumens in a light that can be held in the palm of one’s hand. The OP-6 LED is so bright that looking at the light, even from the side, leaves one flash blinded with dazzling spots of light in front of their eyes for several minutes. IR filters are available, but only for the slightly less bright OP-6 incandescent version that produces 95 lumens. The rear switch can be used for momentary “On” by partially pressing it in or constant “On” by just pressing further. This was easily controlled using the T-Grip’s trigger. Battery life on the LED version is 1.5 hours in constant on mode.
We tested the Stag Arms 6.8mm with ammunition from all current producers: Hornady, Remington and Silver State. The Stag Arms 6.8 functioned flawlessly and had excellent accuracy. Felt recoil was little more than a .223 and required no getting used to, although muzzle blast was noticeably increased over the smaller caliber. The single stage trigger was typical AR, breaking at 5.5 pounds with a bit of creep. We tested our carbine at 50 yards, about the maximum for law enforcement carbine engagements. The 6.8mm essentially replaces short-range .223 carbines with a carbine that is identical in size and shape, but with increased lethality at typical LE engagement ranges. Our best group was just under an inch using Hornady 110-grain TAP (Tactical Application Police) ammo, although all types tested delivered groups that averaged less than 2 inches.
All in all, we like the idea of the 6.8mm SPC as a replacement for .223 carbines for law enforcement. Overpenetration isn’t any more of an issue with the 6.8 than it is with the .223. Although, the 6.8mm’s terminal ballistics are a decided improvement over the smaller caliber round with improved barrier penetration and increased wounding potential. Perhaps best of all is that individuals and agencies wishing to upgrade to the 6.8mm SPC can do so by simply replacing upper receivers and magazines on their M4-type carbines. The manual of arms is identical, so training isn’t an issue and all accessories that work with a 5.56mm M4-type carbine will also work on the 6.8mm SPC. Whether one purchases a complete carbine, or simply upgrades by replacing the upper receiver and 6.8mm magazines, we think that Stag Arms’ 6.8mm SPC rifles and carbines are an idea that will appeal to many tactical teams and patrol officers throughout the country.