Modern Warfare Week

USSOCOM Small Arms Update

During this week’s Special Operations Forces Industry Conference hosted by NDIA, LTC John M. (Tosh) Lancaster, USA, serves as Program Manager SOF Lethality, but the update on SOF small arms and ammunition programs was provided by his boss, PEO – SOF Warrior, COL Joel Babbitt, USA, as part of the entire portfolio.


While there are multiple efforts underway to enhance the lethality of SOF, two primary capabilities were briefed which offer overmatch to our forces who have faced enemy small arms with longer ranges, by increasing their operational envelope.

The first is the Mid-Range Gas Gun (MRGG and pronounced like “Margie”). Chambered in 6.5 Creedmoor, this gas operated rifle will be offered in two variants: Assault and Sniper Support. Consequently, you will see the variants referred to as MRGG-A and MRGG-S respectively. USSOCOM adopted 6.5 CM in 2018 which replaces 7.62mm NATO for Sniper Support Weapons.

The second effort is the Lightweight Machine Gun – Medium (LMG-M) in 338 Norma Mag, a true game changer which offers accurate fire at ranges approaching that of an M2 .50 HMG, but at a dry weapon weight below the M240.

Weapons Timeline

USSOCOM plans to procure both of these weapons using Middle Tier Acquisition.

Mid-Range Gas Gun

A Military User Assessment was conducted in 2019 for MRGG to inform this requirement with COL Babbitt mentioning that SOCOM has, “conquered the intellectual high ground,” on how to best use 6.5 CM. According to industry sources, while numerous companies participated in that event at Camp Atterbury, only Larue and LMT were down selected for further evaluation. Finally, it’s important to note that this requirement is limited to Naval Special Warfare.

Lightweight Machine Gun – Medium

LMG-M promises engagement of both point and area targets out to 2500 meters. MARSOC has already conducted a Combat Evaluation of SIG SAUER’s Light Machine Gun to inform this requirement. According to PEO SOF Warrior, one point of feedback was that Operators were impressed that they were hitting the target with the first round. A fire control system will also be procured via its own program.


Since both of these weapons fire SOF unique calibers (based on use within DoD), SOCOM also has to develop and procure the ammunition. This requires developing cartridges and soliciting industry for their manufacture, just like any other commodity.

Ammo Timeline

While limited amounts of both 6.5 CM and 338 NM ammunition has been procured via OTA, full production will be accomplished via a full and open competitive contract opportunity.

Since it’s in the slide, we’ll also mention that the Lightweight Cased Ammunition program has had some great success with .50 but there are still issues being worked through on the 7.62mm NATO rounds. COL Babbitt related that, “the smaller the caliber, the more difficult to achieve lighter weight.” This is because the case isn’t as large and that’s where the weight reduction is being realized, by transitioning from brass to polymer.

6.5 Creedmoor

COTS ammunition was utilized for the 2018 effort to decide between 260 Remington and 6.5 CM as an intermediary caliber for SOF. Now, a government specified projectile and load have been developed and are being procured.

338 Norma Mag

The 338 NM caliber is also part of the new Mk22 Advanced Sniper Rifle which has been adopted by all the Army and Marine Corps as well as USSOCOM. However, cartridges for use by Machine Guns will be different than those used by snipers. Additionally, MG ammunition requires a link which is a government controlled design. While the sniper round will become service common, the MG round will remain SOF peculiar, at least until the services adopt a 338 NM MG.

20 Responses to “USSOCOM Small Arms Update”

  1. Seamus says:

    I am curious about two things:
    1) How this effort may be affected or become absorbed by the NGSW program
    2) How Civilians can take a page from this and themselves move away from 5.56mm and maintain commonality / parity with the US Military ground forces in terms of equipment, logistics, and range.

    How Civilians will be able to adopt these (or similar) cartridges for use when the killer robots try to take over the world.

    • SSD says:

      1. Since MRGG is an NSW requirement, NGSW has nothing to do with it. While USSOCOM continues to monitor NGSW, there are immediate requirements in 6.5 CM like this which will continue. LAMG in 6,5 CM on the other hand has slowed its pace to monitor NGSW.

      2. 5.56 isn’t going anywhere anytime soon. The Army fields almost 1 million M4/16s. It will continue to serve well into the 2040s.

      • lcpl0420 says:

        SSD, could we get an answer to the bonus question?

        • admin says:

          6.5 CM? It’s readily available.

          Army hasn’t selected a solution yet, but both SIG’s and GD’s (True Velocity) will be commercially available. If DoD selects the CT technology from Textron, they’ll be the only users with only about 120,000 guns in operation. There is one hell of a lot more Guns in the hands of US citizens that use conventional cased cartridges than anything DoD fields. You’ll be able to get Ammo.

  2. Andrew G says:

    That muzzle brake on a 6.5CM rifle is going to be rough on colleagues

    • Scully says:

      They’re going to be suppressed. Most likely a suppressor will be included in the RFP.

  3. Francis Marion says:

    Love the .338 NM but if they want a mid range gas gun what kind of barrel length are they going to need to get 6.5CM to a military useful and effective muzzle velocity? Maybe in a carbine size (16in barrel) 7.62 still makes sense?

    • James says:

      There are starting to be quite a few guys run shorter 6.5’s, mostly 18″ but the 16″ is catching on. The key there is the 147’s loose a lower percentage of their velocity than 123’s and are much sleeker- inside 400 they’re a wash for 308(little worse to little better), beyond that way better . At least that’s my understanding. I think Snipers Hide Lowlight has been running a few 18″ guns for several years.

  4. PO says:

    Since they will be handing out 6.5 CM guns, will a White Claw be issued with each gun as well?

    • Steak TarTar says:

      Wow that’s some hilarious boomer humor

    • ExEd says:

      Bro – PO, 6.5CM is a serious all around cartridge. It’s not just great for PRS and bench shooting, it will take down pretty much all N. American game plus the 2-legging kind found overseas by our favorite four. It does have better TB than a 7.62 NATO and batter range, why the hate?

      And what’s wrong with White Claw?? You more a Truly fan? I get it! Lol 🙂

  5. Strike-Hold says:

    SSD said:
    “1. Since MRGG is an NSW requirement, NGSW has nothing to do with it. While USSOCOM continues to monitor NGSW, there are immediate requirements in 6.5 CM like this which will continue. LAMG in 6,5 CM on the other hand has slowed its pace to monitor NGSW.”

    That’s clear – but does it really make sense for SOCOM to have different weapons and calibers than the regular infantry forces? One could be forgiven for thinking that the NGSW program is looking more like yet another science experiment….

    “2. 5.56 isn’t going anywhere anytime soon. The Army fields almost 1 million M4/16s. It will continue to serve well into the 2040s.”

    Yeah, so surely it would be more logical for 5.56 to be relegated to second-line use, while SOCOM and regular infantry charge forward with 6.5 CM? Instead of having 5.56 NATO, 6.5 CM and 6.8 something all going on simultaneously…

    • Joe says:

      Socom has the money and latitude to get what they want, when they want it, for as short or long a period of time as they feel like, without waiting on big army’s glacial pace.

      If ngsw ends up being better they can pivot to that when the time comes and no one will complain they wasted effort and money pursuing their own thing.

  6. Admin says:

    Does it make sense? Yes, they had .300 Win Mag first and .338 first. It’s why there are acquisition authorities within MFP-11 for when SOF does a mission analysis and determines that what the services can provide aren’t sufficient, they can get what they need. They needed to replace 7.62mm NATO.

  7. Hodge175 says:

    Any traction with the 6mm ARC within the DOD, I always heard it was developed as request within SOCCOM/JSOC.

  8. JP says:

    Is there a viable AP bullet solution on the market for 6.5? Most bullet designs seem general purpose as opposed to armor focused. Thanks!

  9. Bruce says:

    So, the 6.8SPC is dead?

    The 6.5 Grendel has been studiously overlooked, possibly because it is based, ultimately, on the 7.62 x 39 case, via the 6mm PPC..

    It conveniently fits in rifles built around 5.56 NATO ( or M-193). (Hint, hint).

    6.5 CM (A David DeMille creation) needs a platform more AR-10 in size, because of the overall loaded length when topped with a bullet of practical use. (Gene Stoner and Mikhael Kalashnikov will be sitting back with their buddies, laughing their heads off).

    6.5 is about as small as one can go to employ a “useful” tracer element without requiring a ludicrously long bullet that must be stuffed deep into the case to maintain OVERALL max cartridge length, Check out the tap-dancing that goes in to make the M-856 5.5mm tracer round “work”.

    Until an actual professional soldier and ballistician comes up with an actual performance requirement, it is all smoke and mirrors

  10. Matthew Arenson says:

    Bright side the sig 338 ca be converted to 7.62 so it could replace the 240

    • SSD says:

      7.62 is going away. Like 6.8 will replace 5.56, .338 will replace 7.62.