US Army Researchers Developing New Ultra-Light-Weight, High-Velocity Machine Gun

The machine gun is designed to be compact and lightweight like the FN P90 (shown here) while achieving muzzle velocities that rival the full-sized M4.

The United States Army is reportedly developing a new machine gun capable of withstanding higher chamber pressures and allowing for rifle-like bullet velocities out of firearms both lighter and shorter than the M4.  

The firearm will use a new breech and bolt design that allows the action to cycle even under extremely high chamber pressures. This added pressure will, in turn, allow projectile velocities to increase, improving terminal ballistics even in compact, short-barreled weapons. In one test, Army researchers achieved a muzzle velocity of 2,900 feet-per-second from a 10-inch barrel using a cartridge holding only 15 grains of powder. For context, most rifles with 10-inch barrels can only push a 5.56 NATO round 2,500 fps, which limits the round’s effectiveness.

“The goal is to get rifle-like velocities out of a very small weapon that is high capacity, that’s either adaptable for room-clearing or confined spaces,” Zac Wingard, a mechanical engineer at the Combat Capabilities Development Command’s Army Research Laboratory, told TechLink. “Like you’re getting in and out of vehicles or a subterranean environment, but also applicable for remotely operated systems, so think like perimeter security or ground robot or even a drone.”

SEE ALSO: The Army Selects B&T for Its Sub Compact Weapon System

The Army is hoping the technologies can be developed for use both in small, lightweight firearms like the FN P90 and in full-size sniper rifles and belt-fed machineguns. The breech and bolt design would make smaller firearms more effective and would substantially increase the muzzle velocities of larger firearms.

According to TechLink, the U.S. Army’s new 24-inch prototype barrel produced muzzle velocities of 4,600 to 5,750 feet per second. The combustion chamber pressure was increased from 65 ksi to 100 ksi (100,000 pounds per square inch), almost double the pressure seen in the M4 carbine.

“The powder used now in most ammunitions can be tweaked, so it runs at a higher pressure, but the guns can’t handle it,” Alex Michlin, the Army research engineer who invented the new design, told TechLink. “That’s why we designed the new breech, so we can take existing propellant and turn the knob all the way up to 11.”

SEE ALSO: The Army is Gearing Up for a Large-Scale War with Its ‘Big Six’

To accommodate these higher pressures, Michlin developed a bolt that screws into the barrel breech. He also developed a collet that surrounds the cartridge while it’s seated in the chamber, which allows the spent casing to be extracted after firing. The tapered wedges, according to TechLink, reduce extraction forces by 50%, leaving more energy for cycling the bolt.

Photo: TechLink/ Zac Wingard/ARL

Velocity matters because, as Clay Martin outlined in a 2016 article, short-barreled rifles chambered in 5.56 struggle to push rounds fast enough (around 2,700 fps) to turn the .22-caliber projectile into a “tissue blender.” If researchers can increase velocities, infantrymen can enjoy the benefits of small calibers like the 5.56 without having to carry rifles with 16+-inch barrels.   

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About the author: Jordan Michaels has been reviewing firearm-related products for over six years and enjoying them for much longer. With family in Canada, he’s seen first hand how quickly the right to self-defense can be stripped from law-abiding citizens. He escaped that statist paradise at a young age, married a sixth-generation Texan, and currently lives in Tyler. Got a hot tip? Send him an email at

{ 45 comments… add one }
  • KillsQuick July 2, 2019, 9:49 am

    I think their time and money would be better spent on improving the larger caliber Bullpup designs such as 6.5 Creedmoor or .308 even 30.06 with a better recoil buffering system to help keep you on target with the follow up shots, less beating from the recoil, more capability to reach out and touch others, better knock down and killing percentages not to mention availability of field tested and combat proven munitions for these calibers! Bundled into a Bullpup platform you maintain both urban and natural terrain capabilities…gunpowder, AR16 and misfires was a surprise that cost a lot of lives in Vietnam don’t need anymore surprises like that for our People in the future…HOOOAH!!!!

  • Asshat June 17, 2019, 7:51 pm

    Invent a multi-stage/multi-pressure lock. Rather than having it go from 0-100k in lickety split, have it ramp up from a base PSI… One way valves in the chamber that always allow pressures over X through

  • Michael J June 14, 2019, 8:15 pm

    Wondering, who are these going to be used on? Foreign or domestic.

    • Hey June 16, 2019, 12:08 am

      Don’t worry about primitive firearms, worry about 5g. Chief CIA warns a supposedly hack can alter the frequencies that cause advance altermizers diease, they can make the planet retarded with a push of a buttom. Well armed mass freedom loving populations will not do nothing to stop a post WWIII New World Order. Trump is aiding in rushing the use of this technology and even 6g (666g) by his own words, Obama was rushing it too. People are so ignorant just because a president stands up for 1 of the amendment and speaks good about the military, over look his corrupt motives behind close doors. The same can be said about country pride loving Hitler and Sadom Husain, that led their country into suicide warfare. Also they are now bringing South Africa bats, carriers but immuned to Ebola, here to experiment with there immune systems as they eject them with Ebola. I already know how this is going to play out, just like aids was brought into and released from a test tube in this country. How is that possible even if you are drunk and retarded?

      • Ken Garnto June 18, 2019, 8:27 am

        Sir: You need to increase your medications or go see your doctor NOW!

        • Hey June 26, 2019, 1:57 am

          I am sorry the only thing deem as reality to you is main stream media and the average conversation with society. Your comment is a perfect example of why the U.S. can easily fall due to its people are asleep as self pride is used as a tool to bind them of their ignorance. Before you tell me to get medication, you need to get off your lazy a double s and research my past statements. I did not just make the information up out of thin air, just because the president and the media is not addressing it does not mean it is not reality. Following your advice of taking meds is the only way I will become dilusional, just like a majority of the psychatric chemically dependent mass shooters did, mostly starting right after Obama’s second term election as new drugs are introduced with known side effects of violent out burst and suicide. Sound familiar? Probably not to you because shortly after the New Town shooting the media stopped reporting the history substance use of mass shooters, or the fact mass shootings where virtually none existant before 2010, even before background checks. Again everything I have stated to you is not reality to you because main stream media and the general public conversation is the only thing you base truth as and are to lazy to research yourself as with many other people that are asleep.

  • Jim June 14, 2019, 12:27 pm

    I would think that subjecting a barrel to that kind of pressure and velocity is going to heat them up in an instant. Even when I fire my AR at targets, with a string of 20 controlled shots, the barrel is hot, and accuracy is affected. Doubling the pressure more than doubles the heat generated,which increases barrel wear and accuracy. I see problems, or maybe restrictive conditions implemented, when firing such a weapon.

    • Scotty Gunn June 15, 2019, 2:56 pm

      Barrel heat comes from the powder and it’s burning rate, and the bullet creating friction going down the bore. The latter is the main source of heat, powder being a distant second.

  • David June 14, 2019, 12:27 pm

    Isn’t that called re-inventing the wheel, just but the PS90.

  • Lars June 14, 2019, 11:07 am

    Too mission specific, this isn’t being made for widespread use. Sounds like something Spec Ops would be tinkering with, and a specialized suppressor seems required,
    Unsuppressed fire with max, even half max. loads would hinder unit effectiveness.

  • Sarge Fuson June 14, 2019, 10:44 am

    According to the Department of Defense the average number of rounds expended in Vietnam to kill one enemy soldier with an M-16 was 50,000…..that seems to indicate the lack of actual training the soldier got in the area of marksmanship……..don’t reinvent the wheel, properly train them to shoot

    • Kevin June 14, 2019, 11:40 am

      Almost all of the small arms fire that went downrange in RVN was done to suppress the enemy, to keep them from advancing on your position or to keep their heads in the mud and was done without using sights. We probably could have used more time on the range in basic but the fact is, when you came face to face with Charlie, taking time to practice proper sight alignment, trigger control stance and all the other proper shooting techniques, you would have found yourself in second place in the gunfight.

    • Jim June 14, 2019, 12:20 pm

      And, according to what you said, you were not likely in Vietnam to witness the use of those rounds, or the reasons why so much ammo was consumed. Trying to kill an enemy you can hear, but cannot see, is not achieved with accurate rifle fire. And, the military doctrines to “establish fire superiority”, and “suppressive fire” called for rapid fire with little regard for accuracy. Add to that the practice of the “mad minute”, and you have a ton of ammo being used with little regard for accuracy.

      The military citing I read of “50,000 rounds” was the total rounds fired by the U.S. military during the VN conflict, including all training rounds fired stateside, and elsewhere.

      The assumption that our VN infantrymen could not fire their weapons with accuracy is insulting.

    • Jim June 14, 2019, 1:21 pm

      Exactly Sarge! This spray and pray way of thinking is wasteful, wrong, and dangerous! You can see it in our military and even in our police Agencies, When I was in both the US Navy and Police Agencies on the West Coast and in the South we were trained and did not waste ammo. Two quick pulls of the trigger and BOTH rounds were supposed to connect and kill in both agencies.

      • KillsQuick June 15, 2019, 9:41 pm

        During your training we’re you exposed to ambushes of various settings or live fire exercises? It’s hard to aim at let alone hit or kill what you can’t see and Victor Charles was well adapted to his environment and the placement of ambushes as most of us from that era know! The 2-3 round burst was useless under the canopy in the bush unless you had targets in the open or a position where they had to expose themselves in order to return fire or attempt to flee…and in most cases a target rich environment was far and few between hence the term Guerrilla Warfare!

    • Diego Conde June 14, 2019, 2:14 pm

      10-4 👍👍

  • EO June 14, 2019, 10:32 am

    This is a waste of time and money. What tool for what job are they needing that the AR /AK / M1A (w/ or w/o juggernaut chassis) and MP5 isn’t covering?

  • nm June 14, 2019, 10:02 am

    The collect appears to be an adaptation of the floating chamber designed by “Carbine” Williams over 80 years ago. I have a Remington 550-1 in .22 cal. which has one.

  • Daniel hamala June 14, 2019, 9:23 am

    Anytime you heat up a tapered collet, mate it to a bore and let it cool , it will be tight. Also the difference in heat expansion of different metals.

    • Lars June 14, 2019, 11:13 am

      Yeah but hot, tight bores make a lot of guys metal expand…

      • Chris June 14, 2019, 12:41 pm

        Is it getting hot in here?

        • Steve Grife June 17, 2019, 4:38 pm


  • Bad Penguin June 14, 2019, 9:12 am

    I think the author needs to learn a little terminology their is a big difference between, machine guns, sub-machine guns and auto rifles. Had trouble figuring out what he was talking about.

    Also most people dont have a clue as to what 15 gr of powder means and he didnt give the standard load for a 5.56 round is.

    Lastly he says nothing about the caliber or weight of the bullet that was used in the tests. Lehigh Defense has a lightweight solid copper bullet that can be pushed to well over 3000 fps in a rifle.

    • Alan June 14, 2019, 10:45 am

      15 gr of Bullseye is a lot different than 15 gr of 4064, seems like the author just throws out numbers.

      • Lars June 14, 2019, 11:32 am

        Seems like obvious answer is an advanced propellant and improved materials overall in the existing cartridges.
        Those European AP 9mm’s already seem pretty impressive. Perhaps a lightweight(18-36gr) 5.56 with special hardened steel (or anything inexpensive, yet strong)alloy base and core, with jacket and tip being copper could easily get 7-10″ PDW and SBR machine guns into the 3800-4500fps range or greater.

  • Matt June 14, 2019, 9:04 am

    With such high chamber pressure and short barrel, sounds like hell on the ears. I don’t want one!

    • Justin Barnes June 14, 2019, 12:52 pm

      That is exactly what I was thinking. A suppressor had best be worked into the system

  • Scott Riggs June 14, 2019, 8:42 am

    We need to stick to the larger caliber weapons we already have and make them simpler to operate and maintain and not reinvent the wheel..

    • Alan Robinson June 14, 2019, 9:11 am

      Wounding and killing people doesn’t require a ‘larger caliber’, it’s really as simple as that.
      The weapon isn’t designed as an anti vehicle or bunker weapon, and since recoil is a significant factor in follow on shot and placement, higher velocity smaller projectiles make more sense than larger ones.
      You seem to have forgotten Newton’s Third Law.

  • Skypilot June 14, 2019, 8:11 am

    Sounds suspiciously similar to the April Fool’s Day article….. Sorry, not buying it. But gave me a couple of chuckles, so thumbs up to Mr. Michaels!

  • Alan June 14, 2019, 7:24 am

    It won’t take much dirt or powder residue to jam up those acme threads. And what about throat erosion? My cousin pushed his 220 swift improved to 4800 fps with 45 gr bullets and the throat was gone in about 100 rounds.

    • Steven L Waskow June 14, 2019, 9:30 am

      I think you have something there, when you ask about throat erosion. They’re also talking about powders that operate at 100,000 PSI. That’s also going to have an affect on erosion. With higher pressures will also come higher temperatures. Unless they have the barrels made from an alloy that can withstand higher temps as well as pressures.

  • John Smith June 14, 2019, 6:50 am

    Simplicity wins, complexity kills….

  • Mike in a Truck June 14, 2019, 5:52 am

    Here we go again. Squad automatic ammunition design reached its zenith with the 7.62mm.But lets spend millions to get right back to where we started.

    • Traped in California June 14, 2019, 11:07 am

      Hey, someone’s gotta get rich!

      Remember, “…there’s plenty good money to be made, supplyin’ the army with the tools of the trade!”

      -Country Joe & the fish

  • Dr. Strangelove June 14, 2019, 4:47 am

    Sounds like a lot of wear an tear. Those kinds of chamber pressures and resulting heat will eat up a barrel in no time, unless, of course, it’s made from unobtainium, which is only mined in Whatchacallitstan.

    Why not shoot 5.56 from a bullpup, using existing technology and and ammunition?

    • Shortround June 14, 2019, 7:48 am

      Because the big companies runs every thing and want more money. Look what happen with the m-60. Not good enough, had to change. The m-60 could shoot all day long without much trouble. The m-240 is good to go a short time before its rivets start give trouble. But if we stay with what is proven the big companies would not be able to rip us off. FOLLOW THE MONEY TRAIL!!!

      • Mortarman June 14, 2019, 5:43 pm

        The M60 got old and loose at least as fast as the M240 does. I got to see a small share of M60s with rounded and chipped sears, worn-out springs and bad buffers in my company’s arms room back in the post-Vietnam days.

        And I doubt that this is big companies driving this train wreck. This sounds more like the same cast of characters that want to replace all those big, heavy M16 rifles with sexy little M4 carbines but not give up any velocity — and who cares if the barrel life is down to 5,000 rounds (or less) because of amping up the pressure on the 5.56mm round by almost 20 percent to replace the velocity lost.

  • martianone June 14, 2019, 4:41 am

    Even with a pistol size powder charge (15 gr) of powder, that hopefully would be burnt in the barrel, PSI approaching 100000, high probability of bright muzzle flash and unacceptable muzzle blast.

  • Rick June 14, 2019, 3:58 am

    Spray and pray mentality. Limited accuracy in exchange for smaller size. Thinking it’ll be a omplete waste of ammo beyond 75-100 meters.

    • mac1pine June 14, 2019, 8:46 am

      Now I understand the progression that leads to that psa video about the Stormtrooper trying to hit a target and miss regardless the distance or lack thereof…. 😀

      • KO June 14, 2019, 10:10 am

        You just won the thread. 😀

  • BR June 11, 2019, 11:03 am

    100000 psi in a short barrel. Guaranteed to cause deafness after the first shot.
    Design looks very susceptible to fouling.
    That said, I do like the idea of the chamber collet. Great application of tec to solve the sticky chamber.

  • wtsane June 11, 2019, 8:27 am

    We’ve been here before.

    • Mortarman June 14, 2019, 5:49 pm

      Indeed we have.

      The U.S. Army takes pride in doing stupidly difficult things just to prove that they can. Anybody remember how they crowed back in the day about only the U.S. had the know-how to produce difficult-to-manufacture Stellite-lined machine gun barrels (for the m60)?

      Now we want to make PDWs with chamber pressures that sound more fitting for a tank main gun (and probably wear out almost as fast). Can you imagine what fun it will be cleaning the chamber and that locking groove, sitting in the middle of a swamp?

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