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General Dynamics GDATP .338 NM LWMMG (.338 Norma Magnum Lightweight Medium Machine Gun) for Overmatch Capability: Potential Game-Changer for Mobile Infantry (Range Video!)

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By David Crane
defrev (at) gmail (dot) com

All photos and video clips contained in this article were shot by, and are copyrighted. owns the copyright on these photos and video clips. The photos and video clips were shot with a Apple iPhone 4S smartphone with 8MP (8-megapixel) still camera and 1080p HD video camera and Canon PowerShot S90 10-megapixel digital camera (still camera with video capability), respectively.

The following article is property of (DR) and is copyrighted material. If you are reading this article on another website other than, please email us the website address/URL (where the unauthorized DR article reprint is located) at defrev (at) gmail (dot) com. Thank you.

May 17, 2012
Last updated on 5/26/12.

The GDATP .338 NM LWMMG (.338 Norma Magnum Lightweight Medium Machine Gun) is hands down one of the most interesting and important pieces of tactical/combat hardware DefenseReview (DR) scoped this week at NDIA Joint Armaments Conference, Exhibition & Firing Demonstration 2012. It's important because it's a potential game changer and has the potential to redefine the medium machine (MMG) and it's respective combat role as we currently know it. The U.S. military wants overmatch capability, and this weapon will provide that, provided of course it works as advertised.

The GDATP .338 NM LWMMG weighs in at approx 24 lbs–making it lighter than an FN M240 MMG/GPMG (Medium Machine Gun/General Purpose Machine Gun)–and can effectively launch 300-grain (300gr) .338 Norma rounds out to approximately 1700 meters at a cyclic ROF (Rate Of Fire) of 500 rpm (rounds per minute) for overmatch capability, bridging the gap between the FN M240 7.62mm NATO (7.62x51mm NATO) MMG/GPMG and M2HB .50 BMG HMG (Heavy Machine Gun). The relatively low ROF helps keep barrel and weapon heating to a minimum, and also mitigates ammo waste.

Defense Review test-fired the brand new (functional prototype) weapon today at a private shooting range outside Seattle, and we were impressed by the relatively low and smooth felt recoil impulse, which was courtesy of the weapon's in-house designed and developed operating system which incorporates a likewise in-house-designed/developed recoil-attenuation/mitigation system. The LWMMG requires a long trigger pull, which DR assumes is a safety feature, but will probably be tweaked a bit in the future. The weapon's fire selector switch is well placed and was easy for us to manipulate with the firing hand thumb. Case ejection was a bit aggressive, let's just say, and one of DR's correspondents commented that the markings on the spent cartridge cases was a bit inconsistent–but those things are to be expected with a prototype, which this was.

The kicker of course is whether or not the gun is GTG (Good-To-Go), i.e., reliable, accurate and durable in adverse combat conditions at high round count. That's where the rubber meets the proverbial road, and what will ultimately determine the weapon's viability for its conceptual mission profile. And, if it proves to be combat-GTG, the .338 LWMMG is potentially one of the most imporant mobile infantry machine gun developments in decades, and that's not an overstatement. It's an exciting, leap-ahead-type system.

One of the primary challenges, though, will be in introducing a new small-caliber cartridge and disintegrating link into the military logistics ammo supply chain, which is not an easy task. Another challenge is the fact that the .338 LWMMG represents a true ballistic paradigm shift for a sub-30-pound machine gun, so it may be difficult for some people to wrap their heads around, at least until there's some solid field data to demonstrate its combat attributes and advantages.

By the way, according to the GDATP personnel DefenseReview intereviewed at the company's booth, the LWMMG, including its proprietary operating mechanism, was designed and developed in-house from the ground up. It was NOT based on the FN M240 MMG/GPMG series (nor is it a modified M240), as was just speculated by David Reeder at KitUp, based on the LWMMG's physical appearance.

DR plans to publish video footage of our interviews with GDATP personnel and the designer/developer of the .338 Norma Magnum cartridge the .338 NM LWMMG utilizes in the coming days for more detailed exposition on the weapon system. In the meantime, we shot some good photos and videos at the range today. So, we hope you enjoy them, below.

The following information comes directly from the GDATP .338 NM LWMMG data sheet/fact sheet:

"The next generation Lightweight Medium Machine Gun (LWMMG) gives warfighters a distinct advantage in both extended and close-in fighting. Eliminating the gap between 7.62mm and .50 caliber weapons, the LWMMG utilizes the highly efficient .338 Norma Magnum cartridge to offer unmatched accuracy and lethality while extending the battlespace out to an impressive 1,700 meters.

At 1,000 meters, the LWMMG is capable of defeating Level III body armor and incapacitating soft skinned vehicles by delivering over 1,900 foot pounds of energy to the target – more than four
times the terminal effect of the 7.62mm NATO cartridge. Weighing less than 24 pounds and featuring a fully collapsible stock, the LWMMG offers superior mobility and portability in both mounted and dismounted operations.


Caliber: .338
Weight: 24 pounds
Length: 49 inches
Rate of fire: 500 rounds per minute
Ammunition: .338 Norma Magnum
Projectile: 300gr Sierra HPBT, FMJ, AP
Muzzle Velocity: 2,650 feet per second
Barrel Length: 24 inches
Max Effective Range: 1,860 yards (1,700 meters)
Maximum range: 6,170 yards (5,642 meters)
Mount: M192 tripod, or various
vehicle mounts"

GDATP .338 NM LWGG Fact Sheet

The following info comes from the GDATP .338 NM LWMMG press release:

"General Dynamics Unveils New Medium-caliber Machine Gun at Joint Armaments Conference in Seattle

May 15, 2012

CHARLOTTE, N.C. – General Dynamics Armament and Technical Products unveiled a next-generation Lightweight Medium Machine Gun (LWMMG) on May 15 at the Joint Armaments Conference in Seattle, Wash.

Identifying an unmet warfighter need, General Dynamics Armament and Technical Products conducted its own research and development program to develop the LWMMG in just over one year. The weapon is designed for low-cost production and for maximum effectiveness at the small unit level, where weight and lethality are decisive factors.

"The LWMMG is an affordable weapon that closes a current operational gap, providing .50 caliber-like firepower in range and effect at the same weight and size of currently fielded 7.62mm machine guns," said Steve Elgin, vice president and general manager of armament systems. "Weighing in at 24 pounds and featuring a fully collapsible stock, the LWMMG offers superior mobility and portability in both mounted and dismounted operations."

General Dynamics' LWMMG also offers a distinct advantage in both extended and close-in fighting by using the highly efficient .338 Norma Magnum cartridge for increased accuracy and lethality out to 1,700 meters, a distance currently gapped in the operational capabilities of warfighters.

"By employing the larger .338 NM round, the LWMMG delivers twice the range and dramatically increases lethality above the 7.62 round," said Elgin. "In addition, the LWMMG goes beyond providing suppressive fire and gives warfighters the ability to attack point targets at significantly extended ranges."

The LWMMG has a firing rate of 500 rounds per minute, a maximum range of 5,642 meters, and is equipped with quick-change barrel technology. In addition to use by dismounted infantry and on ground vehicles, the weapon can be used as the armament system aboard helicopters and littoral craft, providing greater range and effectiveness for those platforms.

"The LWMMG is a well-designed machine gun ideally suited to provide long-range lethality to U.S. and allied forces," Elgin said.

For more information regarding the LWMMG, visit the General Dynamics exhibit at the Joint Armaments Conference (booth 204, Exhibit Hall, Washington State Convention Center) or visit

For more information about General Dynamics Armament and Technical Products, please visit

More information about General Dynamics is available online at"

General Dynamics GDATP .338 NM LWMMG (.338 Norma Magnum Lightweight Medium Machine Gun) for Overmatch Capability: Potential Game-Changer for Mobile Infantry (Range Video!) by

About David Crane

David Crane started publishing online in 2001. Since that time, governments, military organizations, Special Operators (i.e. professional trigger pullers), agencies, and civilian tactical shooters the world over have come to depend on Defense Review as the authoritative source of news and information on "the latest and greatest" in the field of military defense and tactical technology and hardware, including tactical firearms, ammunition, equipment, gear, and training.

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