Mind The Gap: USSOCOM’s 13-Year Quest for a .338 Norma Magnum Machine Gun

Much of Afghanistan’s geography is mountainous. The topography fades slowly from the steep, tightly packed peaks of the north and east to the tall, rolling piles that line the miles-wide southern valleys. No matter where the battle is in Afghanistan, it’s likely going to involve big elevation and long ranges, a tactical combination that calls for lightweight and far-reaching small arms.

Few people know this better than Staff Sgt. Rudy Gonsor.

Gonsor, a 22-year Special Forces weapons sergeant with six GWOT tours behind him who also works as an instructor with Ridgeline Defense, recalls a mission he had during the summer of 2010 in Uruzgan, Afghanistan. The terrain is a wide, high altitude, hard pan desert valley with 2,000-meter mountains on either side.

Operating in this area is challenging because of the altitude,” says Gonsor. “Loadouts were usually half of your typical combat loadout, with the exception of machine guns. We’d usually focus on having a full load for the machine gun because it gives you the most bang for your buck. When carrying loads, we wouldn’t wear plates and we’d switch to bump helmets to cut weight. Most guys wouldn’t run pistols or anything like that. It was a rifle, four mags, a hand grenade or two, and a radio.”

Gonsor’s team was called on to set up a long-range ambush from the top of a mountain. “It was an ordeal,” he says. “It’s wildly impractical. But in this case, we wanted to cover a known route to a POO [point of origin] site that was about 2,000 to 2,500 meters away.”

The terrain dictated a long-range engagement, he says. The enemy was firing mortars in shoot-and-scoot fashion from defilade, and their motorbike exit route was exposed only from an elevated position. And, that position was a mountaintop across the desert valley.

“At that distance, the 240 wasn’t going to cut it,” says Gonsor. “They’re moving at high speed, so I might’ve employed something like an M107 [sniper] system, but the rate of fire isn’t really enough to get guys on a motorbike. So, we said, ‘well, let’s frickin’ hump an M2 up this bitch.’ So that’s what we did. We split the gun, a tripod, and a hundred- round box of Raufoss rounds between, I think, six guys and set up a long, long-distance ambush. And it worked out pretty well in that particular case.”

You might have a couple of questions after reading that. The first question has a simple answer. The Raufoss round is a .50-caliber high explosive, incendiary, armor-piercing, anti-motorbike round also known as Mk211.

M240 System	800-1,200m Range	Proposed LMG-M System	+2,000m Range	M2 System	2,000m Range
M240	28 lb.	LMG-M	27 lb.	M2HB	84 lb.
ACOG 6×48 Sight	2.8 lb.	LPVO Sight	1.8 lb.	ACOG 6×48 Sight	2.8 lb.
M192 Tripod	11 lb.	M192 Tripod	11 lb.	M3 Tripod	44 lb.
Spare Barrel	6.6 lb.	Spare Barrel	6.5 lb.	Spare Barrel	24 lb.
800 Rds. 7.62 NATO	50 lb.	500 Rds. .338 NM	52 lb.	500 Rds. .50 BMG	150 lb.
Total	98.4 lb.	Total	98.3 lb.	Total	304.8 lb.

Now, the second question is a good one that had a lot of guys — in and out of uniform — scratching their heads back in 2008 to 2009: Why was the choice of a special operations team between the 28-pound M240 with an effective range of 800 to 1,200 meters and the hulking M2 machine gun that weighs 128 pounds in its basic dismountable configuration (gun and tripod) and offers an effective range of 1,800 to 2,000 meters? Why wasn’t there something lighter that was designed for dismounted use that could reach out to over 2,000 meters?

Well, you’ve just been introduced to the concept of the capability gap. 

THE CAPABILITY GAP

“Capability gap” is a term of art used in the military procurement field to describe deficiencies and gain funding for the programs that seek to fill rectify them.

The M240, chambered in 7.62 NATO, began life as the FN Herstal MAG in 1958. The U.S. adopted it in 1977, and it’s been the mainstay of our medium machine gun fleet ever since. It’s a venerable design with incredible reliability and few flaws, chief among them is optics compatibility and limited optic rail space (due to the feed-tray cover), and the need to take the gun off “safe” when running the bolt to clear the gun. 

The 100-year-old M2, chambered in .50 BMG, has long been the choice of U.S. Forces for mounted or emplaced operations where long range or maximum firepower is sought. The old “Ma-Deuce” is a reliable partner in battle as long as you maintain the headspace and timing. But the major issue with the system when it comes to dismounts is the weight. We’re talking 84 pounds for the gun, 44 pounds for the tripod, and roughly 30 pounds for a box of linked ammo. Though it can be trafficked by foot, as illustrated above, it involves making critical logistical trade-offs … and Rudy is still bitching about it 14 years later.

With the LMG-M (lightweight machine gun-medium) program, Special Operations Command (SOCOM) seeks to fill the capability gap between these two weapons with a .338 Norma Magnum machine gun that weighs about the same as an M240 but with range and ballistic power on par with the M2.

THE PROCESS

For SOCOM to get where it is today, evaluating three combat-ready, lightweight .338 NM machine guns, it’s taken a while. 

There’s a lot of water under the bridge going back to 2008 that involves the Army, the Department of Defense’s Irregular Warfare Technical Support Group (formerly known as the Combating Terrorism Technical Support Office), General Dynamics Ordnance and Tactical Systems division, SOCOM, and almost a decade spent testing and evaluating the lightweight medium machine gun concept, the .338 NM machine gun itself, and its ammunition. We can’t cover it all in this story, but wanted to acknowledge the effort of so many people it took to get the LMG-M ball across the line.

In 2017, SOCOM issued an open-source list of attributes it wanted for the LMG-M (it was called the lightweight medium machine gun (LWMMG) back then, asking industry to show them what they could do. It was to be less than 24 pounds with a 24-inch barrel, a rate of fire between 500 and 600 rpm, an effective range past 2,000 meters, have wide optics and aiming accessory compatibility, come with a suppressor and bipod, and be compatible with M240 mounts. The rest was up to the bidder’s imagination.

In 2020, after evaluating its list of attributes using 10 .338 NM machine guns it bought from SIG Sauer, SOCOM issued a draft request for proposal (RFP) with a bigger and more defined set of attributes that represented what it would accept (threshold performance parameters) and what it really wanted (objective performance parameters). In late 2023, it issued a final RFP with adjusted performance parameters and set a February 2024 deadline for submissions.

THE PRESENT DAY

Three companies ended up delivering submissions to SOCOM. Those are the three guns we describe below (presented in alphabetical order), the Ohio Ordnance Works REAPR, SIG Sauer’s SIG-MMG 338, and True Velocity’s RM 338.

SPECIFICATION COMPARISON CHART

Make	SIG Sauer	True Velocity	Ohio Ordnance Works
Model	SIG-MMG 338	RM 338	REAPR
Caliber	.338 Norma Magnum (7.62 NATO configurable)	.338 Norma Magnum (7.62 NATO configurable)	.338 Norma Magnum (7.62 NATO configurable)
Operating System	Gas piston-operated, w/rotating, open bolt	Gas operated, short recoil, impulse averaging	Blowback, roller-delayed, open bolt
Weight (w/bipod)	25.5 lb.	25.0 lb.	26 lb. (w/carry handle)
Weight (w/bipod, supp.)	28 lb.	26.8 lb.	27.24 lb.
Spare Barrel Weight	7.35 lb.	UNDISCLOSED	6 lb.
Bipod Weight	1 lb.	UNDISCLOSED	1.75 lb.
Adjustable Rate of Fire	Normal and adverse	No	No
Rate of Fire	650 rpm +/- 50 Adverse 700 RPM +/-50	500 rpm	600 rpm
Rate of Fire w/Suppressor	650 rpm +/- 50 rpm (on Normal)	500 rpm (no change)	600 rpm +/-
System MRBS	>3,500 rounds	UNDISCLOSED	UNDISCLOSED
Barrel Swap Interval	Equivalent to M240	2 minutes of rapid rate or 10 minutes of sustained fire	UNDISCLOSED
OAL (ready to fire)	50.5 in.	51.5 in.	51 in.
OAL (stock folded)	43 in.	43.5 in.	44 in.
OAL (w/suppressor)	54.5 in.	55.25 in.	55.5 in.
Barrel Length	24 in.	24 in.	24.4 in.
Effective Range (point target)	UNDISCLOSED	UNDISCLOSED	UNDISCLOSED
Effective Range (area target)	2,000+ meters	2,000+ meters	1,500-2,000+ meters
Dispersion @ 100m w/.338 NM	Semi-auto:1.95 in. AMR Full-auto: 4.18 AMR	UNDISCLOSED	Semi-auto: 2.5-4 AMR
Alternate Length Barrel Available	Yes	UNDISCLOSED	UNDISCLOSED
High Pressure/Hybrid Ammo Compatible	Yes	Yes	UNDISCLOSED
Clear WPN w/o Disengaging Safety	Yes	Yes	Yes
Belt Feed Side	Left or right (configurable)	Left	Left or right (configurable)
Spade Fire Control Option	Yes	Yes	Yes
Suppressor Make/Model	SIG Sauer SLX-MG	Delta P Design Brevis IV	Huxwrx Custom
Suppressor Weight	2.5 lb.	1.8 lb.	1.24 lb.
Suppressor Length	6 in.	4.5 in.	6.7 in.
Sound Reduction	9 dB average	20 dB	UNDISCLOSED

Note: In 2021, General Dynamics was one of the three LMG-M competitors when it dropped out of the competition and passed its torch to a company called Lonestar Future Weapons. (LFW was a subsidiary of True Velocity and its partner on the Army’s NSGW contract.) A couple months later, True Velocity rolled the brand into their own. So, outside of this article, you might hear True Velocity’s submission variously called the GD or the LFWs submission, but they are all the same machine gun.

Now let’s take a look at the three new guns born out of this project. 

OHIO ORDNANCE WORKS: REAPER 

• Caliber: .338 Norma 
• Magnum (7.62 NATO configurable)
• Barrel Length: 24.4 inches
• OAL System Length: 
• 55.5 inches
• System Weight: 27.24 pounds (gun, bipod, suppressor)
• Suppressor: Huxwrx Custom

MOTIVATION: 

“We’re a machine gun company,” says Robert Landies, III, OOW’s president, “it’s our niche, our specialty.” The company has a long, healthy business making its own versions of the M2, M240, and M249 machine guns and selling them all over the world, but he wonders for how long those 60-plus-year-old guns put bread on the table. When he heard about the .338 machine gun requirement at an NDIA conference a while back, it clicked for him.

“With the Marine Corps and SOCOM looking at it, it was kind of clear. This is solving a problem. We’ve got a lot of veterans that work here. They can tell you, comparing the M240 to the Russian PKM firing 7.62x54R, they can outshoot us. So, the benefit and the value were clear. We talked about it internally years ago and decided to really put our minds together and go down this path.”

DELIVERY CAPABILITY: 

OOW employs about 130 people, nearly a third of them vets, at its northeastern Ohio factory. The company designs and machines in-house, bringing in extrusions, castings, and plastics as raw material. They make their own barrels, make all their own critical components, do their own welding, assembly, testing, and all the other things you’d expect from a manufacturer of old-school belt-feds.

But, over the last 10 years, they’ve invested heavily in technology. They’ve been 3D printing metal parts and using modern testing and evaluation suites for product development.

DESIGN & FEATURES: 

An engineer, Landies led the OOW’s REAPR engineering effort himself. He and his team lived and breathed the project for the last four years. They sat down and discussed the strengths and weaknesses of the current crop of medium machine guns and what considerations had to be made when designing one for the .338 NM cartridge. The biggest thing that came out of the discussion was that they didn’t want to deal with a gas system. They chose to go blowback for its lower parts count, durability, and consistency.

The next area they wanted to address was optics compatibility. You can only shoot as far as you can see, and the .338 spits bullets a long way. They came up with the MDOF (multiple degrees of freedom) top cover design that slides to the left and opens forward without interfering with rail-mounted optics. 

That means it can wear a full-size scope, unlike its competitors that are limited to stubby optics because of their feed trays. It’ll clear the objective bell of a large diameter optic like a Leupold Mk5 5-25 or a Vortex Razor 4.5-27. It might look delicate, but OOW says its durability has been thoroughly vetted through testing and use.

They also wanted to address portability. And did they ever. The REAPR is the only MMG we know of that breaks down three components — receiver, handguard, and barrel — for transport in a ruck. Barrel swaps on the REAPR are novel, too. Instead of activating a latch on a handle, the operator pushes in on the barrel and twists it until it locks or unlocks. 

Regarding recoil mitigation, OOW is cagey in describing the way it deals with it. They say they have multiple ways to dump energy that include the guns two mainsprings, a buffer system in the back of the gun, and they’re also using energy to feed and cycle the gun. Other nice touches are the folding charging handle that can be run on either side of the gun, lower feed pawls that will hold a belt in place while loading, and an 8- to 12-pound trigger. The gun can be set up for left or right feed, for coaxial use, and, with its downward ejection, it’s fine for mounted use in land, sea, or air.

PERFORMANCE: 

The gun went from CAD to the range in about 9.5 months, they say. And they spent about 150K rounds in testing, to date. They didn’t want to talk about the gun’s MRBS (mean rounds between stoppages) count, or the gun’s accuracy, only allowing that its accuracy meets or exceeds the contract’s objective requirements.

OUTLOOK: 

As far as the REAPR’s chances of becoming the LMG-M, the gun itself stands out for its durable and reliable blowback operation and its future-forward features like the sliding feed tray cover and modular transportability. Looking at the company’s large work force, loads of manufacturing space, hundreds of machines, and a history of large-scale machine gun manufacturing, OOW’s should rate highly on SOCOM’s deliverability index. If the gun meets all the performance objectives, we’re guessing the only thing that might cause some hand-wringing at SOCOM is its price compared to its competitors. 

SIG Sauer: SIG-MMG 338

• Caliber: .338 Norma Magnum (7.62 NATO configurable)
• Barrel Length: 24 inches
• OAL System Length: 54.5 inches
• System Weight: 28 pounds (gun, bipod, suppressor)
• Suppressor: SIG Sauer SLX-MG

MOTIVATION: 

There’s no doubt that SIG Sauer is on a tear when it comes to small arms contracts for the U.S. Military. They’re the only company to have its pistol, rifle, and machine gun fielded by U.S. Forces. In talking to SIG’s lead for the program, Jason St. John, it’s clear the company placed a high priority on winning this contract. He says the initiative comes directly from its CEO Ron Cohen and his desire to put SIG on the map as a premier defense contractor. 

In 2017, when the LMG-M opportunity arose, SIG recognized that adding a belt-fed machine gun to its product portfolio was a once-in-a-generation opportunity, and it grabbed onto it with both hands. The company immediately invested millions in its .338 machine gun development effort. That paid off, as it put them in an ideal position to shift gears to the 6.8 NGSW program, which saw them design, build, test, and deliver the SIG-LMG that’s now the Army’s XM250 machine gun. 

Now, SIG sees the LMG-M program as a way to further validate its market position and outfit our nation’s elite combat force with a leap-ahead capability.

DELIVERY CAPABILITY: 

With its selection by the Army for the M9 pistol, and both NGSW components, SIG has established its ability to deliver weapon systems to the U.S. Military. With its hundreds of experienced employees, modern machines, and all the other systems and resources of a first-rate firearms manufacturer, it’s a good bet that they’ll get high marks in SOCOM’s delivery capability rating.

DESIGN & FEATURES: 

Looking at the guts of the SIG-MMG 338, it’s not hard to see that SIG’s engineers took a great deal of inspiration from its own MCX gas operating system. The short-stroke gas piston is clean running and reliable. It also lends itself to an adjustable gas system that allows the gun to have two rates of fire, which we hear SOCOM is fond of having. They’ve also incorporated a reciprocating barrel along with a hydraulic dampener to tame recoil.

With weight being a huge factor, SIG approached the design of the gun in reverse, making prioritizing weight over reliability in the initial design. As failures occurred in testing, parts were beefed up until the gun achieved its reliability objective. An example of how this approach was applied is the gun’s apparent use of composite construction, where the receiver is aluminum and heavier steel is used strategically in high wear areas of the action.

There’s a massive amount of top rail space, though it’s interrupted by the side-opening feed tray cover. It’s designed to return to within 1 AMR at 100 yards of its zero when opened and closed. It does this with a biased hinge and a steel insert and latch. The handguard features a flip-open top that snaps out of the way for barrel changes. And barrel swaps are fast thanks to the placement of release buttons on the outside and inside of the handle, which accommodates operation from either side of the gun.

PERFORMANCE: 

SIG says they burned through more than a million rounds of .338 NM in development and testing the MMG 338. That’s a lot of rounds. And that’s in addition to whatever it took to develop the 7.62 NATO exchange kit that SOCOM requires for the LMG-M. With all that testing, SIG is proud to report the gun’s MRBS is north of 3,500 rounds, though we’re guessing SIG is holding its cards closely and underreporting this figure. For comparison, the M240 reportedly runs about 3,000 MRBS. On the accuracy front, SIG reports the gun prints 1.95-inch AMR groups in semi and 4.18 AMR groups in full auto. (You can think of those AMR numbers roughly as MOA measurements.)

OUTLOOK: 

SIG built a potent machine gun in the MMG 338. At 25.5 pounds in its lightest combat-capable configuration, it’s right between its competitors. It probably leads the pack in terms of combined polish and reliability. And, because of its lineage to the Army’s XM250 bringing some shared components, there may be some cost savings SIG could leverage to keep the price low.

Considering the aggressive manner in which SIG priced the P320 to win the Army’s M17/M18 contract, we’ll guess that they’ll price the MMG aggressively, too, and hope that eventually leads to a wider military adoption and greater profit.

True Velocity: RM 338

• Caliber:.338 Norma Magnum (7.62 NATO configurable)
• Barrel Length: 24 inches
• OAL System Length: 55.25 inches (as shown)
• System Weight: 26.8 pounds (as shown)
• Suppressor: Delta P Design, Inc. Brevis IV

Dave Stouffer says the Gas system is based on the M60, of which General Dynamic built tens of thousands.

MOTIVATION: 

This gun is the OG of the program. General Dynamics literally began the program with its development and the delivery of two RM 338’s to the government all the way back in 2011. True Velocity bought the General Dynamic’s small arms business and with it came the RM 338 and a bunch of the GD personnel who have been involved in the 338 program since its inception. 

Stouffer, an engineer who developed the RM 338 for GD, and Kevin Sims, formerly in business development and marketing for GD, are now True Velocity executives. For this crew, the project began as a way to bring much-needed change to our warfighters and has become a bit of a personal quest they want to see through. 

Sims says he remembers being laughed out of offices when pitching the .338 NM capability more than a decade ago, and that the team would love some recognition for its long effort as instrumental in the government’s identification of the M240-M2 capability gap.

DELIVERY CAPABILITY: 

True Velocity is an ammo company. But, not just any ammo company. They’ve pioneered incredibly advanced manufacturing processes that make traditional ammo factories look like medieval blacksmiths shops by comparison. 

We’re talking touch-free manufacturing with robots, lasers, and super computers producing millions of rounds with manufacturing tolerances NASA would be proud of. True Velocity plans on bringing its next-gen manufacturing capability to bear on RM 338 production at some point. But, in the meantime, it plans on using the old-school machine shop of a subsidiary to make the guns major components, outsourcing the rest, and doing its own QA, assembly, and testing.

DESIGN & FEATURES: 

The RM 338’s headline feature is its namesake recoil mitigation technology. It’s called Short Recoil Impulse Averaging, and it was developed back in 2010-11 as part of the package initially pitched to the government. Sims says things like slight barrel articulation are examples of the way they are managing recoil forces and momentum throughout the weapon system. Stouffer further explains that the gun is somewhat unique in that it operates off both gas and short recoil. The combination, he says, allows the gun’s other mechanical recoil mitigating properties to function more effectively than they would if operating off one or the other.

The simple and rugged receiver is made of riveted steel and is easy and inexpensive to make. The gas system is, unsurprisingly, based on the low-maintenance M60 gas system, since the GD design team had plenty of experience with it after making tens of thousands of them. Because it has lower feed pawls, belts will stay on the tray when the cover is open, and it can be stuff-loaded. 

There’s a long section of Pic rail on the rear portion of the receiver to accommodate decently sized optics (though probably not a 5-25). And, lastly, the bipod is extremely robust and is quickly deployed with a pull of a lever from its stowed position beneath the handguard.

PERFORMANCE: 

While touting the gun’s 2.5-4 AMR accuracy, Stouffer declined to give specifics on the gun’s reliability, only saying, “We fired over 330,000 rounds of instrumented test and an engineering test of this weapon system over the last 14 years. So, it is extremely robust and reliable … What you’re looking at now is the culmination of U.S. government operational evaluations and user evaluations, every demo, all the feedback, everything has gone into it.”

OUTLOOK: 

The RM 338 is the most mature of the LMG-M submissions. Having shot it, we can say it’s impressively controllable. In the prone, it feels more like firing a 6.5 Creedmoor than a .338. In full auto, there’s no muzzle rise. Zero. That’s an incredible capability to have in a long-range machine gun. That alone may be enough of a differentiator for SOCOM to choose it. The rest of the gun functionality isn’t as elegant or refined as the others. But the core capability is there, and if the gun is as reliable as SOCOM expects, and it represents the best value to the government, then it’s got a great shot at becoming the LMG-M.