The L1A1 Armourer

AND IN THIS CORNER: The Barrett M468 Challenges the M16/M4/XM8 [from Soldier Tech, www.military.com]

The race to replace the M16/M4 family of rifles is on -- and Barrett has its own worthy contender in the M468 rifle, which features an improved, more powerful 6.8mm cartridge.

The Barrett M468: Upper receiver M468/M16 conversion kit (Image from Barrett Website).

Barrett M468 Rifle: The Skinny

Name:
M468 Rifle (Barrett Firearms)

Type of Equipment:
Battle rifle

Killer Features:

Firepower: Rifle uses 6.8mm cartridge which has 50% more stopping power than the M16's 5.56mm cartridge
Ease of adaptability: Selective Integration Rail (S.I.R.) hand guard allows all existing military night vision devices, combat optics, and weapon accessories to be mounted on rifle, without need for adjustments

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For 40 years, the M16/M4 rifle family has reigned as the U.S. military's standard-issue battle rifle. Any gun manufacturer that wants to tackle that stranglehold must also take on the legacy issues that have plagued the M16/M4 series over the years: maintenance and reliability issues, overheating (especially in the M4s), and the less than stellar stopping power and penetrating capabilities of the Remington .223 (5.56mm NATO) cartridge these rifles shoot.

In a previous SoldierTech article we had a sneak preview of one challenger to the M16/M4's throne, the Heckler and Koch XM8. It did away with many of the problems noted above, although it still uses the same Remington .223 cartridge that the current M16/M4 rifle uses. That left an opening for the Murfreesboro, Tennessee arms manufacturer, Barrett Firearms Manufacturing, Inc. Barrett has joined the fray with the introduction of the 6.8mm M468 rifle, a sturdy challenger to the XM8.

Barrett's aim is to eliminate the M16/M4's weaknesses while retaining its strengths -- in short, improve the rifle's combat characteristics, but also simplify operator transition to the new weapon, and reduce maintenance and acquisition costs.

A rifle such as the M16 can be divided into two major components: the upper and lower receivers. The upper receiver houses all of the firing components of the rifle: the bolt assembly, the barrel, chamber, and the gas operating tube, as well as any iron sights or attached optics. The lower receiver forms the "user interface" portion of the rifle, incorporating the butt stock, magazine well, trigger assembly and handgrip. In the M16's case, all of its operational problems are associated with the upper receiver. Consequentially, the Barrett M468 is essentially a new and improved upper receiver mated to an existing M16/M4 series lower receiver (there is no need to buy a complete weapon).

Stepping Up: The Remington 6.8mm SPC (Special Purpose Cartridge)

The core component of the Barrett M468 is Remington's new 6.8mm SPC (Special Purpose Cartridge). Indeed, the rifle's name comes from the combination of M4 and 6.8mm. Introduced by Remington Arms in 2004, the 6.8mm (.270 caliber) SPC is more lethal than the 5.56mm cartridge, without a significant increase in overall bullet dimensions. Though slightly larger than the standard M16 cartridge (6.8x43mm as opposed to 5.56x45mm), current issue M16 magazines can easily be reconfigured to accept the new cartridge. In addition, while the SPC has a slightly lower muzzle velocity than the 5.56mm cartridge, its larger mass makes it ballistically similar to the lighter 5.56mm round (in terms of accuracy and bullet drop), and it delivers half again as much kinetic energy. In real terms, this means that the 6.8mm SPC has the same relative trajectory as the 5.56mm (which allows for the M468 to be fired and treated essentially like a 5.56mm M16), but with 50% more stopping power, and a bullet speed of 2650 feet per second from a sixteen and one-half inch barrel, delivering 1715 foot-pounds of energy, with a six hundred meter effective range.

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PRI-manufacture 6.8x43mm SPC 25-round magazine.

Keep It Simple

Flexibility is also the watchword with the M468, as it employs the ARMS Inc. S.I.R. (Selective Integration Rail) hand guard, which allows all existing military night vision devices, combat optics, and weapon accessories (such as bipods) to be mounted on it. The SIR system not only reduces the integration costs of the weapon (there is no need to purchase new optics specifically tailored to the weapon), but also gives the military the ability to selectively field the weapon and its systems. For example, every Heckler & Koch XM8 requires an integrated electro-optical combat sight, whereas the Barrett M468 can be issued as a stand-alone weapon (the SIR system comes with integrated "flip up" style iron sights), with optional items such as the M68 CCO, PAC-4 and PEQ-2 issued to units based on their MTOE (Modified Table of Organization and Equipment) and operational readiness level (Active Component forces have a higher OR level than National Guard formations, for example).

The Barrett M468.

The SIR system allows for the rapid integration of the core system (the M468) into all levels of the military, while distribution of auxiliary systems (such as optics and night vision devices) could be based on unit need and budgetary considerations. In addition, the M468 should be completely adaptable (through the use of modified hand guards) for use with existing secondary weapons, such as the M203 40mm grenade launcher (which has been a standard issue, squad level weapon for the last 20 years) and the 12 gauge LSS under-barrel shotgun. The ability to mount these pre-existing weapons means that new weapons (such as the 40mm launcher that would be used with the XM8) wouldn't need to be purchased as additional items.

Simply put, the greatest advantage the Barrett M468 has over contenders such as the H&K XM8 is improved lethality. By going to the more powerful Remington 6.8mm SPC, Barrett has produced a rifle that is more lethal than any other battle rifle chambered for 5.56mm NATO, yet does not suffer from a significant loss in magazine capacity (as would have been the case if the rifle had been chambered for the much larger 7.62mm NATO cartridge). By going to a heavier bolt carrier group and stiffer recoil spring, Barrett has also addressed the one unresolved legacy issue regarding the M16s reliability under combat conditions. These two factors, coupled with its compatibility with existing M16 accessories and attachments, would seem to make it the hands-down favorite to replace the M16.

Barrett M468 Specifications

Caliber:
Remington 6.8mm SPC

Builder:
Barrett Rifles

Overall Length:
35.4 inches (stock extended)
32 inches (stock retracted)

Barrel Length:
16 inches (chrome-lined)

Rate of Twist:
6 groove, one-in-10 inch RHT

Sighting System:
Folding Front Sight and Gas Block

Price:
Retail Price: $2,535

Upper Conversion Kit Price: $1,494

Weight:
7.3 lbs

Muzzle Velocity:
2600 feet per second

Magazine Capacity:
5, 10, 15, and 25 Round Magazine Configurations

Operation:
Semi-Automatic, Gas Operated,
Dual Spring Extractor System, Muzzle Brake, Two-Stage Trigger

A Matter of Life and Death: The Virtues of 6.8mm

The 6.8mm advantage: A chart comparing the 6.8mm cartridge with the standard issue 5.56mm cartridge (image by Barrett).

Generally speaking, armor penetration is measured in inches (or fractions thereof) of steel plate. Both the 5.56mm and 6.8mm cartridges mentioned in this article won't penetrate a steel plate a quarter of an inch thick -- think Clint Eastwood's improvised chest plate in "A Fistful of Dollars" -- - but they can both shoot through all non-insert body armor types (though the 5.56 loses more energy on impact, and is significantly less lethal). So what's the other differences between them?

What it all boils down to is that when the 5.56mm cartridge was first introduced to U.S. combat rifles, it was adopted because of its size and its fit with the U.S. "shoot-to-wound" philosophy of the time. While the 7.62mm NATO round used in the M14 is much more powerful than the 5.56mm bullet, it is also much larger; a soldier can carry twice as many 5.56mm bullets as he can 7.62mm. In extended combat operations (wars lasting years), it was also estimated that wounded combatants would require more logistical support than dead ones -- with this in mind, the U.S. adopted the 5.56 round, since if the bullet did not kill outright, it would certainly cause a serious enough injury that the casualty would be hospitalized for a significant amount of time.

Unfortunately, as demonstrated by recent conflicts such as Somalia in 1991, the 5.56 simply lacks the "shoot-to-kill" lethality (numerous accounts exist of Somalian insurgents being shot repeatedly before they finally either died or lost the will to fight) needed to stop an attacker. This shift in philosophy (from shoot-to-wound to shoot-to-kill) is what the 6.8mm SPC represents. Though not much larger than the 5.56 round, it is undeniably more lethal. The real world effect of adopting this round can be seen how CQB (Close Quarter Battle) is conducted. In a room-by-room fight, the more rapidly an enemy combatant can be taken out, the safer the operation is for friendly forces. Since there's no time to evaluate a target's condition in a firefight, soldiers engaged in room-by-room combat will shoot each individual 3-5 times to ensure that they are dead. With a heavier, more lethal round, they need only shoot 2-3 times. While this may not seem like a significant improvement, it can shave valuable seconds off of engagement times (as the shooter shifts between targets) and mean the difference between having bullets left over at the end of the fight -- or having to swap magazines while surrounded by live bad guys.

PRI News Release

The 6.8mm Rem SPC Cartridge - SPC Order Form

PRI has participated with several other companies and individuals in the development of the new 6.8mm Rem SPC cartridge, an improved power cartridge for the AR15, M16 family of firearms.

The new cartridge design allows a 115 grain bullet to be fired out of the M16 at velocities of 2850 feet per second. This new power in the M16 creates many expanded capabilities for the weapon; check it out at the Remington website under ammunition. We have also built uppers that are not only more powerful but give great improvements in rifle accuracy at extended ranges.

PRI has been altering and building uppers to accept and fire the new cartridges since the earliest stages of development and is familiar with the configuration required to make the system work. We have manufactured such parts as the barrel, the magazines, the bolts and other parts particular to the 6.8mm caliber.

PRI will be able to sell the parts or uppers to create the new capability rifles at the upcoming 2004 SHOT Show in Las Vegas. We look forward to seeing our customers at booth #1009 and discussing our many new products; please stop and see us.

Watch for more info on the 6.8mm in coming issues of Guns and Ammo, Guns and Weapons for Law Enforcement, and Soldier of Fortune magazines.

David Dunlap, Precision Reflex, Inc.
710 Streine Drive
New Bremen, OH 45869
419-629-2603

[MasterGunner's Note via Dave Dunlap: The 6.8x43mm SPC magazines used by the Barrett M468 and PRI rifle are made of steel. Standard M16/M4 aluminum magazines are not strong enough to be loaded to with the larger diameter 6.8mm SPC round. Also the spring, follower, and guide ribs of the steel magazine are slightly different from the Standard G.I. magazines. PRI manufactures 5, 10, 15, and 25 round magazines for the 6.8mm SPC round. Contact us at www.pri-mounts.com.]

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