US Army Considers Ditching 5.56 NATO Round

There’s no secret that the military has been looking to ditch the M4 / M16 for quite some time. The last serious effort was the Individual Carbine competition, announced in 2011 and cancelled in 2013 when none of the guns involved met the specification. Word comes now from the Army Times that the military is at it again, but might be trying to change things the other way around.

Instead of selecting a better rifle for the 5.56 NATO cartridge, the military might be selecting a new cartridge altogether and asking manufacturers to create a gun to shoot it. From the article:

Army researchers are testing half a dozen ammunition variants in “intermediate calibers,” which falls between the current 7.62 mm and 5.56 mm rounds, to create a new light machine gun and inform the next-generation individual assault rifle/round combo.

The weapon designs being tested will be “unconventional,” officials said, and likely not one that is currently commercially available.

Some intermediate calibers being tested include the .260 Remington, 6.5 Creedmoor, .264 USA as well as other non-commercial intermediate calibers, including cased telescoped ammo, Army officials said.

I’d love to see a caseless design come out as the winner of this competition; I think it could cut down on production costs and provide a more “green” solution to ammunition now that you’re not leaving lead and carbon covered pieces of brass all over the world.

That said, my bet is on something like 6.8 SPC. A cartridge that will (mostly) fit the existing magazines and crates used in the military supply chain would cut down on the cost of implementation and sweeten the deal for military brass.

According to reports we should know the winner in the next couple months, and then the real fun can start.

comments

  1. avatar Norincojay says:

    The 6.5 G people are going to be upset you said 6.8SPC!

    1. avatar BigDaveinVT says:

      I presume you’re speaking of 6.5 Grendel. If so then no tears from me. I love my Grendel but its following seems to be dwindling. The LGS hasn’t stocked Grendel for nearly a year.

      Velocity seems to be its downfall. A long range competitor I ran into said he had worked with 6.5 G for a while but just couldn’t get enough speed out of it. He finally gave up and moved to Creedmoore (but didn’t settle on that round either).

      However 6.5 G would add bullet weight and greater effective range over the 5.56 while retaining at least a small amount of what made the military switch to the 5.56 in the first place – more rounds per pound over .308.

    2. avatar OODAloop says:

      Meh, not upset, just a bit disappointed. The 6.5 Grendel offers a better ballistic coefficient, slightly lighter weight (than 6.8 SPC) and excellent overall ballistics. It would make a great round, however like every AR-15 platform wildcat gone mild, it’s expensive to run.

    3. avatar Chainman says:

      6.5 Grendel is the down range solution sought, within the ar-15 platform, the Grendel offers minimum component change, boilt, barrel, mag. mod, and it’s 800 to 1200 meters, little INCREMENTAL CARTRIDGE WEIGHT differential vs. 5.56, and, down range, kicks 308 and 6.8 ass.
      6.8 after certain ranges looses it’s effectiveness.
      I posted a year ago March, (2016) in TFB, the 6.5 Grendel was the inside fav.
      Ammo weight variance between 5.56 and 6.5 Grendel is negligible, and down range, Grendel passes .308 at 700 yds. and waves goodby.
      6.8 can’t meet long distance reqs.
      6.5 Grendel it’s gonna be.
      Creedmore may end up being the new AR 10 platform.
      Ammo cost? I’m buying Vladimer’s 100 gr. FMJ for 20 to 22 cents per rnd., to negotiate a Nostler or Hornady class bullet in 120 gr. weight in low cost NO PROBLEM…BIDDERS WELCOME, mfgers would “kill each other ” pun intended to produce a bullet in .264 that meets the needs.
      Watch n see.

  2. avatar Evan says:

    They won’t switch. They will test like 10 cartridges then do nothing.

    1. avatar Frank in VA says:

      ….and spend like 2 million on testing ammo before deciding to change nothing.

      1. avatar Robert Farago says:

        Pocket change for Uncle Sam.

        1. avatar The Gray Poseur says:

          Yawn…just the latest iteration of making money flow from the ammo vendors to the Generals.

    2. avatar John in TX (Was CT) says:

      Yes… but that’s not necessarily a bad thing. It seems to me like it’s prudent to re-examine your sacred cows from time to time, and there have been some interesting new cartridges developed since the 5.56×45.

      Waste of time? Waste of money? Sure, but they have to examine it at some point, why not now?

    3. avatar Hank says:

      After twisting arms all around the world to adopt the 5.56mm NATO I sorely doubt the US will suddenly decide to adopt a new caliber.

      We heard this nonsense when the military started looking for a new handgun. All the old .45 farts were convinced their beloved 1911’s would be new again.

  3. avatar Uncle Mike says:

    Honestly, enough of the “green” justifications for bullets. In a war, the lead and brass from spent 5.56 rounds will be the least of our worries. The scorched cities and millions of rotting corpses will be a far greater ecological problem.

    1. avatar Tom Moscone says:

      …they would also be smaller, lighter, and cheaper. Meaning that soldiers could carry and shoot more rounds without increasing their load weight or decreasing their ammunition endurance.

      There are a lot of reasons to examine caseless.

      1. avatar Daniel Harris says:

        I don’t think service members will carry more rounds. I think magazines will still be issued in the standard 30 round size. I walked and ran around just fine in Iraq and Afghanistan with the weight of 5.56 NATO. However , the government is a business, so I would think as long as it’s cheaper and meets the requirements, they will buy it.

    2. avatar Cousin Fokker says:

      Oh Uncle Mike you ray of sunshine!!!

    3. avatar Binder says:

      I think the use of lead in actual combat is not the issue as much as the use in training and having to clean up the ranges

      1. avatar Daniel Harris says:

        All casings get picked up after every range exercise anyway. I don’t personally think the US military is THAT worried about lead.

  4. avatar Rick says:

    5.56 is a great round within a specific set of circumstances, but extended ranges are a problem unless they start to issue longer barrels a’la Marine IAR. It’s just very velocity dependent, and for the ranges we’re seeing in the GWoT, it’s not great.

    It will still remain my go to for HD.

    The 6.5 caseless sounds great, but that’s a long logistics trail, doable, but the planning doesn’t seem to a great skill right now. Plus, we seem to have an issue with actually finalizing anything.

  5. avatar Norincojay says:

    If they go with something like the 6.5 C then they would be using a rifle more in the AR10 size class. There have been some recent designs like POF and Mega getting the size of the bolt carrier down to shorten and lighten up the rifle.

    Definitely would be cool. But a 6.8 diameter is better for ballistic wounding than the 6.5. Per some study where they found 6.5 best accuracy coefficient and 7 best wounding and 6.8 in between both in both ways. Something like that.

  6. avatar James Earl Hoffa says:

    10 millimeter explosive tip caseless. Use a small plastic charge on the back of every bullet put the bullets in some type of magazine possibly a rotary type magazine and then use battery charge to detonate the plastic charge on the back of the bullet. You could control the rate of fire by simply pushing on an LED screen absolutely amazing.

    1. avatar Norincojay says:

      A couple years ago I got my first IPhone! Well the next day I slipped in the bathroom and hit my head on the toilet. When I awoke I had a design of a rifle very similar to what you mentioned but with an IPhone in the stock. It does all the ballistic calculations for distance, wind, altitude, humidity, temp and so on that adjusts your scope for targeting. The phone could also control the rate of fire be used for heads up display with the battlefield and friendlys and bad guys with gps location over google maps. It was awesome!

      1. avatar Gaston's love child says:

        Plus, you can order a pizza, and watch netflix on that bad boy.

      2. avatar BLAMMO says:

        And once that baby gets up to 88 mph, you’re gonna see some serious shit.

    2. avatar JC says:

      …says the guy who knows nothing about explosives.

      Pressure’s 20 times higher than smokeless, anything easy to “detonate” is also dangerous etc. etc. etc.

      If it were that simple, they’d have done it by the 1980s.

  7. avatar Todd P. says:

    .25 SPC

  8. avatar Gov. William J Le Petomane says:

    The 6.8 seems to make the most sense to me, but if they were going to switch to that I’d think that they’d have done it by now.

  9. avatar Brad says:

    The Army considered buying the SGT York, the RAH-66 Comanche, the ARH-70 Slapaho, and the Bradley Stingray too. Just more money to spend on contractors, nothing to see, move along.

    1. avatar Manse Jolly says:

      I have not heard the name “Sgt. York” in a very long time. My unit was tasked to go to Ft. Hunter-Liggett, Ca in 85 AFAIR, to be ground troops used for testing that POS. We stayed out there for 6 months.

  10. avatar Gary Howell says:

    I’m really interested to see what our Operator teams have to say. Hope they are vocal and have the chance to input some into the planning. Perhaps they’d try it out on the teams before wide distribution. The teams should be the first darn place the planners petition.

    1. avatar Tile floor says:

      They already get more leeway than the average grunt, many using 77gr Black Hills ammunition instead of the mass produced stuff the grunts get.

      People get really wrapped around the axle about JSOC dudes and what they use. Don’t get me wrong, they’re incredibly trained and skilled. But don’t. Be so quick to gloss over your rank and file infantryman. Training has come a long way, and having been one I can tell you they can handle themselves more than okay. Give them a say too since they’ll be the ones actually toting the stuff around.

      1. avatar Wsuufg says:

        I’m more inclined to take the SF community’s opinions on ammo performance considering they are far more likely to have seen how our current (hopped up on pcp, allah, and IV drip) enemies react to being perforated by our current gear.

      2. avatar David Walters says:

        JSOC wins skirmishes and tend to buy up all the hair gel in any local in which they “operate”.

        Regulars win wars and smell to high heavens and look like crap doing it.

        That’s all you need to know.

  11. avatar YAR0892 says:

    I’ve got $20 that says I’ll still be qualifying with a 5.56 round if not on a M4-A1 in 2025, most probably until I retire- in 2049.

  12. avatar CHLChris says:

    I don’t understand why they would switch right now. What, exactly, is broken that needs to be fixed? 5.56 has always been a study in pros and cons, with lightness of the ammo winning out over pure efficacy. Wouldn’t our warriors prefer a load-out with more pew-pews for the same weight? And why did y’all choose a photo of 300Blk? What a worthless switch that would be!

    1. avatar Allen says:

      I think the photo is a 458 SOCOM.

    2. avatar Adam says:

      Military has a huge budget and there is no way that the top guys aren’t going to spend it. If there is extra money laying around come the end of the year that might mean that their budget gets cut.

      No way will the military ever say “Yeah, you give us too much money. We end up just wasting billions.” No, they are just gonna keep tossing it into that sweet R and D trash fire.

    3. avatar David Walters says:

      OK. I’ll try to answer that.

      In the jungles of Vietnam, I hear that the average range between combatants was about 100 yards.

      In the more recent conflicts in central Asia the average range exceeds that by 5 – 10 fold.

      Our opponents in both conflicts used weapons that 7.62 X 39 both in personal weapons and in crew served weapons to great effect. When the engagement ranges got longer and especially when the automatic crew served weapons of the enemy were engaged the out ranged us. Essentially, our selection of the NATO cartridge put us at a disadvantage.

      Comments?

      1. avatar Bob A says:

        What is the kill rate? Thankfully, we have not seen as many flag draped coffins come back as you would expect if the enemy was using their weapons to good effect.
        They have range but are not effective. Our current arms can match theirs easily. People think every soldier needs to be a 1,000 yard accurate shooter. That will not happen with current equipment.
        The enemy takes pot-shots at long distances. They are using enfields and other old, large caliber rifles and weapons left over from wars long past. We can plink all day with 7.62 and .50 cal weapons. The make up of combat units ensure an infantry soldier has support, all day long.

  13. avatar Hannibal says:

    Caseless has it’s uses but until you figure out how to deal with the heat of an automatic weapon’s chamber, war isn’t one of them.

    1. avatar uncommon_sense says:

      Oh, good point. I forgot that the brass acts as a sort of cooling “fluid” on machine guns helping to remove heat from the chamber. Perhaps if someone designed (up front) added cooling fins to the chamber to facilitate extra cooling without brass casing?

      1. avatar Hasdrubal says:

        Like the shroud on a WW1 Lewis gun?

      2. avatar samuraichatter says:

        If you go cartridgeless it would get around that issue and still probably be cooler. I know there was talk awhile ago about it with tanks. Basically, fluid that is atomized/made aerosol and projectiles in something like a hopper ; no case is needed . However, at that point complexity and the way-out-there factor means you might as well go with energy weapons 🙂

    2. avatar anaxis says:

      Also…. IIRC caseless designers have always had problems with durability. If the propellant block has cracked due to manufacturing defect or battlefield damage, it causes uneven/incomplete ignition, and very difficult-to-clear jams, as the systems lack shell extractors.

      Granted, caseless is likely an awesome last step before troops get portable rail-guns & 40W phased plasma rifles…. but I imagine polymer-composite case ammo would become a thing before caseless does.

  14. avatar Mark N. says:

    I thought the 6.8 SPC was a “been there, done that” kind of thing. Why would the Army go back over trodden ground?

    1. avatar Bob A says:

      It was deemed the best overall cartridge. I guess none of the brass was going to make any money out of it. Lowly enlisted came up with it and it did not cost enough for them to skim off some during retirement/working for the contractor getting the contract.

  15. avatar Chris says:

    Hey, a 308 is never late.

    Just sayin’

    1. avatar Ed says:

      ^^This^^ +1

      I don’t see why anyone wouldn’t prefer 7.62×51 over any of the listed test rounds.
      .308= one round,one down. 5.56=two/three rounds,one down. .308 20round mag = 20 down….5.56 30 round mag = 10-15 down. 6.5 and 6.8 are ok, but I don’t think either are quite as well suited for battle as 7.62×51/.308, plus there are already multiple platforms in service that already use that caliber.
      Most of us civilians have enough sense to know its a good idea to have a consolidated number of calibers, apparently the army hasn’t got the memo yet.

      1. avatar Nate says:

        Carry 200 rounds of 5.56 for a week, then carry 200 rounds of 7.62 for a week.

        1. avatar Ed says:

          Yeah, im sure the extra 1.5lbs. is the deciding factor here. Cry that river to all the 90 lb. V.C. that humped a SKS and 200 rounds of 7.62×39 on stripper clips or 8 AK mags in a commie chest carrier. That dog don’t hunt. I bet there are PLENTY of guys overseas who would trade in their .22 cal gun for a AR-10 quicker than you can say 62 gr.
          It’s akin to the difference between stabbing someone with a ice pick or a bowie knife. I’ll take the bowie everytime.

        2. avatar Hank says:

          Ed and Nate, while I agree with you that .308 is a superior round, and it should be an option, having humped it myself, the problem isn’t necessarily the weight of the ammo, or even the gun you carry. It’s all the other bullshit you have to carry on top of it. I can and have carried several hundred rounds of .308, while lugging the 240 in Iraq… it’s a bitch, but it’s when you throw on the other 60 pounds of body armor, and numerous amounts of other gear that you REALLY start to feel it. The military could increase caliber and therefore weight, but they need to reduce it in other areas. Personally I think we also help to do away with some needless equipment. Like the tripod to the 240. There’s absolutely no need to hump around a tri pod on patrol. I’ve never ever met a soldier or marine who deployed a tripod in a damn firefight. They should be used in static positions only. You could then increase ammon capacity where you remove needless equipment like that.

        3. avatar Sam I Am says:

          Seems to me that since WW2, the Army fields every infantryman as a stand-alone sapper battalion. Look at the footage from the Normandy invasion. Who thought it was tactically smart to strap 80lbs onto a soldier and run across 200yrds of wet sand? Look at the enemies we have fought since. US soldiers carry everything a soldier could need for a month, the enemies have carried a weapon and enough ammunition to get the job done. Strike fast, strike hard. Serving as a tracked vehicle is senseless.

        4. avatar Nate says:

          Hank, that’s what I am getting at. Yes .308 is better, but 200 rounds is 5 pounds of 5.56 and 10 pounds of 7.62 (not the 1.5 Ed mentioned – I think he’s talking about x39), and then you throw in a heavier gun to boot. It should absolutely be an option, but when a lot more ammo is expended in area suppression (what are the stats on rounds fired for each enemy combatant killed?) having an entire squad using .308 would limit that ability for volume of fire in situations where immediate resupply is not an option – which is why they have the 249 and 240.

          It seems to me (from an outsider’s point of view) that there is a big difference between how general infantry units engage vs the special ops types (several SEAL accounts have mentioned they usually roll with only 3 mags for speed, and that they usually don’t expend them… but their engagements are MUCH different).

  16. avatar Denner says:

    243 Winchester? A necked down .308. With a barrel swap you can shoot .308 , 243 Winchester, and there’s one other.

    1. avatar Anner says:

      358 Winchester was the earliest. There have been others since.

  17. avatar GRA says:

    I like the 6.8 SPC round. I try to keep in mind how much more weight a larger cartridge is to hump and how many rounds you can still get in to a reasonably sized mag without taking up too much space. I just hope they don’t go with anything lighter than what they already have.

    Regardless … this will be interesting to see.

  18. avatar matty 9 says:

    no one’s even said “Phased plasma rifle, something in the 40 mega watt range” yet?????? The POTG are slipping!!!

    1. avatar Scott says:

      Just 40 watts. Electric trains require 5 to 12 megawatts of power to run.

  19. avatar J says:

    And the winner is m855a1

  20. avatar Hank says:

    I highly doubt it. The US military will be using 5.56 and the AR platform until firearms are superseded by energy weapons. I give that about 50 – 75 years. Every decade until then, they will come along and present the above, and end up sticking with 5.56 and AR, everytime.

    1. avatar No one of consequence says:

      So … you’re saying they’re the B-52s of the Army?

      1. avatar Hank says:

        That’s actually a great way to put it.

        1. avatar Anner says:

          In terms of longevity and technology.

  21. avatar jwm says:

    Double barrel pump action .410. Belt and magazine fed. War winner right there.

    1. avatar Kaban says:

      Why bother with .410? DP-12 with 12G depleted uranium sabot slugs!

      1. avatar jwm says:

        Depleted geraniums? What the hell has flowers gots to do with war?

        1. avatar Kaban says:

          Flowers have unlimited applications in warfare. That 1998 movie, “The Patriot”, clearly states that flowers are, among other things, omnipotent anti-viral treatment. I bet they would be curing hemorraghic fevers, but that is late, great Tom Clancy’s turf.

  22. avatar No one of consequence says:

    Let’s wait and see.

    Basically, I see this as the equivalent of a shopper in a grocery store pulling a few new brands off the shelf just to see how they stack up against “the usual.” There’s an excellent chance nothing major will change, if for no other reason than the new stuff isn’t perceived to have a big enough advantage over the existing stuff to have to deal with replacing stockpiles.

    However, this sort of thing does accomplish two things. First, it lets the military formally “keep tabs” – in a documented, defensible-if-ever-implemented sort of way – on recent developments in small arms ammo that might be useful to the military. Second, by doing it every so often, trends and overall improvement paths can be seen, and possibly tied into other related R&D (either private sector or gov’t lab) to come up with a significantly overall better solution, faster. Nick’s comments re caseless fall into this category; a little while back, TFB had a nice series of articles with the relevant program manager for that research.

  23. avatar JC says:

    This is so easy, it’s pathetic that they keep stumbling around, hoping to trip over a solution.

    1.) Do some tests to figure out the maximum recoil the troops can handle.

    2.) Pick your distance. The maximum at which you want effective wounding (or whatever).

    3.) Assuming we’re sticking to FMJ, we know there’s a velocity floor below which FMJ is ineffective.

    4.) Choose a diameter that offers a high enough BC to get your velocity minimum at your distance, at a recoil level that your troops can handle.

    5.) Calculate that muzzle energy, to reach that minimum velocity at your maximum distance. We now know roughly the amount of powder it will take to get there.

    6.) Pick your case shape with sufficient capacity, based on accuracy vs. feeding vs. mag capacity.

    7.) You’re done with the science. The rest is supply chain management.

    1. avatar JC says:

      Give me a million bucks, and I’ll knock this out in a year, with test firings and effectiveness results.

      Oh wait– government. Three years and five million bucks…

      I can tell you right now it’s going to be between 6 and 6.5mm diameter, and between 100 and 125 grains.

  24. avatar Anonymous says:

    I’d love to see a caseless design come out as the winner of this competition, I think it could cut down on production costs and provide a more “green” solution to ammunition now that you’re not leaving lead and carbon covered pieces of brass all over the world.

    Instead you’ll have lead and carbon covered pieces of plastic all over the world. I don’t see it as any greener than brass – at all. In large quantities the plastic can leach their decomposing by-products into the soil and water table. If they get under the soil and out of the sun, they’ll likely stay there for about 10,000 years.

    1. avatar JC says:

      Yeah, carbon pollution is a problem, being all synthetic and all. Just another man-made element screwing up the dirt… kinda like lead. After all, it’s created by unicorns– it didn’t come out of the ground or anything originally…

      And metallic lead is super-water-soluble. LOL.

      1. avatar Pvt.Joker says:

        ^THIS^

  25. avatar RCC says:

    Just repeating bad history

    M1 was originally designed to be about .280 then someone said (McArthur?) no we have all this old WW1 30-06 make it that.

    Then the NATO cartridge was going to be 7 mm or .280 and USA said no it had to be .30 Then the USA promptly changed to 5.56.

    What the on ground soldiers want and need will have nothing to do what happens.

  26. avatar st381183 says:

    In my best Indian Jones voice,”Fools, bureaucratic fools.”

    1. avatar Cloudbuster says:

      So what you’re saying is that we need to deploy the Ark of the Covenant?

  27. avatar James Earl Hoffa says:

    When is the military going to finally understand that one rifle platform is not going to suffice for every job. It’s like when they went from the M14 to the M16 they were expecting great things from the 5.56 Nato round and it turned out to be a pretty good jungle warfare round because the distances where usually under 300 meters. You have to remember this is an assault rifle cartridge and it was never intended to shoot 600 meters and be as effective as say 30 caliber round 7.62 NATO. The problem is they want a one gun solution and that’s just not going to happen the 5.56 is good for infantry units the problem is the barrel link that they are using is 14.5 inches long for a 5.56 NATO cartridge to get the full velocity it has to go 20 inches of barrel. They need to increase the barrel Links at least a 16 inches if not 18 and they get the performance out of the 5.56 NATO that they want.

  28. avatar uncommon_sense says:

    If the U.S. military wants improved “stopping power” at longer ranges than current 5.56 x 45mm, why not just go to hollowpoint 62 grain bullets in existing 5.56 x 45mm brass cases? While full metal jacket spitzer bullets do nothing more than poke tiny holes at relatively paltry velocities (less than 2,000 fps?), hollowpoint bullets (that expand reliably at said “paltry” velocities) are a LOT more devastating. I suspect that simply changing to 62 grain hollowpoint bullets will increase the maximum effective range by about 100 to 150 yards.

    1. avatar Snatchums says:

      Right? My understanding is even though we do generally abide by the Hauge Convention of 1899 we never signed the expanding ammunition clause so there is nothing legally preventing us from using hollow point bullets in military service. I’m thinking the 6.8mm projectile with a hollow point and a tungsten carbide core for versatility on soft and hard targets.

      1. avatar RandallOfLegend says:

        Special forces already uses the hollow tipped 5.56 😉

  29. avatar Model 31 says:

    I expect the next military round will be .22LR with biodegradable plastic projectiles. This lightweight military round will enable all personnel to carry 525 rounds -even the ones that can’t do all the pull-ups. The universal round will be employed in both rifle and sidearm applications in order to simplify procurement and distribution. As a smaller cartridge, a lower environmental impact goal will be achieved. The round will be safer for military personnel than 5.56mm and 7.62mm when our middle eastern allies decide to go jihad on Americans at the base. With deadly range out to 1.5 miles, sniper teams will transition over to the new round once a retrofit kit becomes available. This round is substantially quieter than the 5.56mm round which will result in less hearing damage for combat veterans and will be less likely to give away a soldier’s position during combat. It is truly the round for the 21st century.

  30. avatar Dracon1201 says:

    This is a bad move. Even if they go through with it, who says it will be the right cartridge for the next war? What if it is Europe’s cities on fire. At that point I want M4s back. .223 is very good for Urban Combat, especially when concerned with hit probability. This isn’t gearing up for the next war, it’s building a cartridge for the GWOT.

  31. avatar uncommon_sense says:

    Why not use a .30 caliber bullet and just increase the powder capacity a bit over current 7.62 x 39 so that you get a muzzle velocity around 2700 fps? That would still tend to reduce space/weight while improving performance and range. And the resulting cartridge would probably fit at least 25 cartridges in the same size as current 30 round magazines for 5.56 x 45mm NATO. And you would still enjoy much reduced recoil over 7.62 x 51mm NATO.

    Or for that matter, why not use a slightly lower-power version of .243 Winchester so that you get 2700 fps at the muzzle with 100 grain bullets? Again, that would be a more effective round without as much additional space/weight as 7.62 x 51mm NATO and nowhere near the recoil of 7.62 x 51mm NATO.

    Now, make either bullet above a hollowpoint design that expands at impact velocities down to 1400 fps and we would really be in business.

    1. avatar JC says:

      Of course. Read my post.

    2. avatar Geoff PR says:

      “Why not use a .30 caliber bullet and just increase the powder capacity a bit over current 7.62 x 39…”

      Like hot-rodding .300 Blackout?

      That would have the least impact on the supply side, just issue ready to rock uppers and ammo.

      The Spec Op folks can use subsonic loads with a can for their ‘wet work’, the ability to clear buildings-rooms without ear pro would be a major plus for them…

  32. avatar Sam I Am says:

    “A cartridge that will (mostly) fit the existing magazines and crates used in the military supply chain would cut down on the cost of implementation and sweeten the deal for military brass.”

    No one gets promoted for saving money; period. Rank expands with dollars under authority.

  33. avatar FlamencoD says:

    To me, this seems relatively easy. Instead of a new cartridge, use a better bullet in the 5.56 NATO round – I think that is the main downfall based on what I’ve read. Go with something in the 65-69 grain weight. To me, that’s a good combination of bullet weight vs. velocity vs BC. Design the bullet tip to induce tumbling more reliably down to lower velocities. Then, as barrels wear, replace the 14.5″ barrels with 16.5″ mid-length barrels for a little extra velocity and less wear on the receiver and BCG. For CQB soldiers can shorten the butt stock an inch or so, so the overall rifle length is only 1″ longer compared to the 14.5″ barreled M4. For the rifles used in the desert, go with 18″ barrels since the engagement distances tend to be higher. Bringing the butt stock in another inch and the rifle will only be marginally longer than the 16.5″ barreled rifles. That 18″ barrel will get nearly full velocity out of the 5.56 NATO round (since 20″ is standard barrel length for 5.56 NATO).

    IF they must change, I wouldn’t mind them going to 6.8 SPC, as I want an upper chambered in 6.8 SPC II but can’t justify it because the ammo is not as cheap as .223 Rem. or 5.56. If the military uses it, I would hope the civilian price comes down.

  34. avatar Rusty Chains says:

    They will talk and test and in the end they will do nothing. The physics of this are well understood with only the changes of better controlled burning powders, and some improvement of projectile materials. The only real change that could deliver significant enhancement would be going to an expanding hollow point projectile, and I doubt they have the stones to deal with the political backlash that would cause.

  35. avatar Sam Wright says:

    I vote for the 300 ACC Blackout. It hits almost as hard as the 7.62, yet takes up no more room than a 5.56, but I really want it so that the round will become more diverse and popular(cheaper) for me. Heh still not a bad round that should be tested against the various 6.5’s that probably will be considered.

    1. avatar Jon in CO says:

      Honestly, for everything the .gov needs, 300blk is the best option. All they need is some new barrels and gas tubes. All of the armorers are trained and the conversion would be swift. Save them money on silencers too, no longer needing anything except 30cal. All of the weapons, mags, transport equipment, pouches, packs are already good to go. If for any reason they need to issue a 5.56, it can be converted retroactively in the field if need be.

      I’d love to see a 249 in 300blk…

  36. avatar Scott says:

    Forget this intermediate cartridge stuff. Let’s use a battle rifle chambered for .700 Nitro Express. Go big or go home, am I right?

  37. avatar shoehorn says:

    6.5 Grendel outdistances everything, and is still shootable in select-fire, especially over the AKM rounds.
    That reason is what has kept the 5.56 alive this long. Going backwards in distance won’t happen.
    The Grendel is the clear winner with distance, thump, and controllability and still in the AR 15 platform.

    1. avatar Bob A says:

      Distance, which can gained by 6.5 Grendel is not the main concern driving the desire for a new rifle. Five hundred yards or greater shots are not going to be effective without better optics and a substantial amount of additional training.
      6.8 SPC II has already been scientifically tested and chosen as the best overall cartridge. Loaded to proper powder levels you will get a 600 yard accurate rifle. Hitting at over 300 yards consistently in battle starts the dreamers of long distance cartridges dreaming. Without a lot more training and better optics, any range over 300 yards is wishful thinking.
      Terminal ballistics should trump distance, assuming the distance is reasonable (minimum 300 yards).

  38. avatar Joseph says:

    I for one am still hoping Grendel gets in here – it kinda fits all the conjecture for dimensions and performance, plus it’s relatively low pressure to where it would fit nicely within the specs of shellshock cases, if that were a possibility down the road. (to say nothing of barrel life)

    It sure as hell has a shorter OAL versus most of the rounds being considered here, weighs less, and has 95%+ of the performance of the other rounds.

    However as it isn’t mentioned, I’m guessing it got skipped over and won’t be even considered, which saddens me as it could have meant great things when feeding my AR.

  39. avatar TruthTellers says:

    I think the greater likelihood is that they may switch from the 62 grain bullets to 77 grain bullets for better barrier penetration and better performance against wind drift.

    Personally I think the 5.56 is weak, but I don’t see 6.5, 6.8, or .300 BLK as being so far and away better that it’s worth the cost for a marginal performance gain. Shoot the 5.56 from an 18-20 inch barrel and it’ll get to the velocity it was designed to from the Vietnam era and be more effective.

    1. avatar Joseph says:

      Well, they’re going for greater range, is the main argument. Even a relatively low velocity 6.5 round like 6.5 grendel offers a 50%+ effective range advantage over 5.56 NATO – while keeping to a 14-16″ barrel. Besides that, there is marginally improved wounding characteristics.

      Now what doesn’t make sense, to me at least, are the suggestions that we should go to hugely longer rounds for only marginal improvement over that. But apparently weight and OAL, alongside recoil, aren’t issues or something in this whole consideration, given most of the rounds on the table that have been stated… which is rather confusing to me, honestly.

  40. avatar Agammamon says:

    “I’d love to see a caseless design come out as the winner of this competition; I think it could cut down on production costs and provide a more “green” solution to ammunition now that you’re not leaving lead and carbon covered pieces of brass all over the world.”

    The problem with this is that the problems with durability and reliability with caseless ammo haven’t been solved yet. Caseless don’t like oils, don’t handle wear as well as brass, brass acts as a heat sink keeping the weapon cooler (and reducing the likelyhood of cooking off the ammo) by taking waste heat with it when its ejected and, frankly, you’re still tossing *whole pieces of carbon covered lead around* – a little lead residue on the brass is negligble compared to the amount of lead sprayed out in the bullet itself.

  41. avatar Justin Watson says:

    They should just switch to 50 bmg, heavier but GANGSTA

  42. avatar Kaban says:

    Unless they define very clear goals and priorities, the whole thing is unlikely to result anything. There is simply no wunderround with 5.56 OAL that has it all.

    Current 6.8 SPC loadings are okay for increased oomph up close, but vastly overrated for longer ranges. Shame, those new 70+gr 5.56s has better drop!

    Newer 5.56 loadings managed to selectively cure the round’s deficiencies (77gr loadings from longer barrel are vast improvement in long-range capability). But IIRC, with heavier bullets it displays questionable performance for all-out combat at 0-300y range. I may be very well wrong on this one.

    6.5 Grendel is trifle slow in short barrel, enjoys least drop in energy at 0-500y range, but all that broken bolts etc. might have hurt otherwise good idea. Had it been otherwise, Grendel might be best overall replacement.

    Then there is matter of other weapons. If US Army goes pre-70 Soviet, and DMs with .308 rifles proliferate, there is nothing wrong with 6.8 SPC as main infantry round.

  43. avatar Michael Eyer says:

    They already looked at 6.8 SPC but test was before improvement of 6.8. The new 6.8 SPC II has the best of all worlds for a new military round in auto and semi auto. A very respectable midrange round, ammo still light, weapon light and light recoil for better control in auto (rock n roll) just to name a few. Sorry 6.5 G & C fans they are both outstanding weapons and fine sniper weapons but for general military weapon the 6.8 SPC II wins!

  44. avatar Corey says:

    Caseless ammo….? Very funny. Go read about caseless on Wikipedia, who isnt even a gold standard on anything, and they bring the 3 major issues to light…

    What to go to? Honestly 6.5 or 6.8 looks to be the best option. The only thing I really see wrong with them? They really dont have the raw velocity that the military needs with only say a 16″ barrel. The one thing 6.5 does bring to the table? Legitimate 600 yard performance. I would like to see them go to to something like 6.5X47 or 6.5 CM but then we are back to large frame AR’s which are heavy all around. Why no 260? Because screw Remington IMHO…

    223 is fine. They need to stop chopping the barrels off of everything, and run a 69gr bullet that doesnt have some shitty steel core in it. War isnt meant to be “green”. Who ever thought about trying to make war “green” anyway?

  45. avatar dan says:

    What about that fancy new .277 Wolverine round? That’s just cramming a 6.8 projectile into a 5.56 case, similar to the .300 blackout.

    1. avatar Matt in SC says:

      That’s what I was thinking about, not many people know about it. Here’s the wiki page for it…
      https://en.m.wikipedia.org/wiki/.277_Wolverine

      Seems like a pretty good cartridge.

  46. avatar kap says:

    Military switched rounds in Vietnam so the Politicians could get filthy rich by promoting it, getting kickbacks etc.
    Today there is not one General that gives a Shit about the Combat load of an 11Bravo since forever, look a the Omaha landing films you see GI’S with humongous weights on their backs getting mowed down! cause they can’t move.
    Army and Marines now are into spray and pray vs Marksmanship, so it takes 300 round for a KIA, Most young men are city kids and Some actually think that the Recoil of the .223 is severe, so next will be a real ass kicker LOL.
    basically the Army and Marines want short range stopping Power of a ma deuce in 10-300 meter max without recoil and weight.

  47. avatar tsbhoa.p.jr says:

    considers.

  48. avatar Jake C says:

    I hope if they swap they do it to 300 Blackout, it’s a good round.

  49. avatar Williams says:

    I really hope this doesn’t go through. 5.56 is fine, it’s the M855 that sucks. The Mk318 is what we need to switch to. I really don’t want to switch to a heavier round. A full combat load of 5.56 is unpleasant enough to hump around.

  50. avatar adverse4 says:

    BB rifles, light, quiet, and annoys people that you shoot with them.

  51. avatar Pete says:

    The last time they tried this approach, M1 Carbine was the result. The cartridge was an excellent performer on paper.

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