BACK TO THE FUTURE? Textron Displays Newest Polymer-Cased Telescoped Firing Rifle

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It looks like it could be back to the future for the US Army, if Textron’s new carbine design is any indication of what’s to come. The company unveiled its latest prototype of a cased, telescoped ammunition-firing rifle at Modern Day Marine 2016 in Quantico, VA, on Tuesday. The rifle, which weighs 8.7 pounds unloaded and feeds from a 20-round magazine, is reported to fire a 123gr 6.5mm bullet at 3,000 ft/s, producing 3,350 J and rivaling the existing 7.62 NATO in energy.’s KitUp! reports:

Textron Systems unveiled its new 6.5mm case-telescoped carbine at Modern Day Marine 2016.

The weighted model represents Textron’s latest effort to develop a new age of infantry weapons that fire weight-saving, case-telescoped ammunition.

Textron has made significant advancements in this technology with its Light Weight Small Arms Technology, or LSAT – an Army funded program that has so far yielded working lightweight machine guns in both 5.56mm and 7.62mm.

The new 6.5 CS carbine emerged out of an intermediate caliber study Textron conducted in 2014, according to Ben Cole, project engineer.

Currently, the empty weight of the mock-up carbine is 8.7 pounds. A magazine loaded with 20 rounds of case-telescoped 6.5mm ammunition adds one pound. An M4A1 weighs 7.74 pounds empty and about 8.74 pounds with a loaded 30-round mag.

Case-telescoped ammunition is about 40-percent lighter when you compare it to the standard brass ammo in the same caliber, Cole said.

The 123 grain 6.5mm has a muzzle velocity of about 3,000 feet per second, Cole said.

Comparatively, the 62 grain bullet on the M855A1 has a muzzle velocity of 2,970 feet per second, according to U.S. Army data.

“If you take this 6.5mm bullet at our muzzle velocity, it’s 300 percent more down-range energy than the M855A1,” Cole said. “So for a minimal weight gain, you would have significantly more down-range lethality.”

Textron officials hope to have a working prototype to begin testing early next year, Cole said.

“We are trying to go after the next requirement for soldier rifles,” Cole said.

The rifle appears to be the latest variant of a weapon that had been shown off in a slideshow for Picatinny’s CTSAS program earlier this year, where it was quoted (at the time) as weighing 9.7lbs. Since no changes between the two weapons are apparent, it seems that 8.7lbs is the unloaded weight, and 9.7lbs is the loaded weight. We can also see that the muzzle performance of 123gr at 3,000 ft/s is consistent with the downrange energy at 1,200 meters of 300 ft-lbs displayed in the same slideshow, suggesting that this weapon also uses the 15.4 gram per shot 6.5mm ammunition shown there. This would mean magazine weight for this system is 146 grams, consistent with my estimates for the same.

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I note that their loaded weight figures for the M4A1 Carbine appear to be for a fully loaded M4A1 with optic, PEQ, and other accessories. Unloaded and stripped, as the weight for Textron carbine seems to have been measured, an M4A1 weighs about 6.5 pounds.

123gr at 3,000 ft/s is extremely high performance for a weapon of this type, but a loaded (without accessories) weapon weight of 9.7 pounds is also very high, especially for a rifle that only holds 20 rounds in its magazine. Is the tradeoff in weight worth the extra performance? How would such a high performance round (assuming correspondingly high recoil) affect the shooter’s ability to put rounds on target quickly and accurately? It’s difficult to know, but it seems that this iteration of the Textron carbine is more M14 in weight and performance than M4 Carbine.

H/T poliorcetes, Military Guns & Ammunition forum

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • Major Tom

    I’d have to wonder the recoil too. If it retains .308-like ballistics but is a ton lighter, then I could see it being a battle rifle alternative to the SCAR or EBR with options for a DMR.

    I’m still curious about how far along Textron is with their other LSAT programs, specifically their LMG. It’s been awhile since I’ve heard anything.

    • PK

      The information you’re curious about is publicly available. At a glance, there are two presentations on the LSAT progress this year so far.

  • Martin Grønsdal

    my question is:

    by perfecting caseless, are we not inventing a better sail, instead of making motorboats?

    • ostiariusalpha

      Who said anything about caseless? That section of the development program was totally dropped several years ago, only the polymer cased ammo is still going forward and its numerous advantages over conventional metallic cartridges are pretty easy to justify.

      • Martin Grønsdal

        my question is:

        by perfecting polymer cases, are we not inventing a better sail, instead of making motorboats?

        • ostiariusalpha


        • No, because sails are a mature technology that actually works. Polymer case ammo is more like trying to replace motorboats with sailboats driven by a motor powering a huge forward-facing fan.

        • Ebby123

          Lol. Laser technology just isnt there yet..

          Well, Laser technology probably is, but BATTERY technology is not.

  • PK

    I’m not sure about your level of excitement, but it seems like maybe, just maybe, the CTA concept will be going forward this time. Finally.

  • BattleshipGrey

    What’s with all the added bulk? It’s starting to look like a Beretta ARX. Is all that necessary to fire the scoped ammo?

    • therealgreenplease

      I had the same thought. What’s with all of that extra mass forward of the magazine well? The original M-16 was pretty friggin light and, in the same barrel length, we haven’t managed to shave off too much weight thus far. IMO, this is the exception, not the rule, in industrial design. I see a lot of potential for reducing the weight of the rifle Textron above.

      With that said, I wonder if that round would have too much recoil for a general infantry rifle.

      • Parvusimperator

        Careful. The M4 weighs about as much (unloaded, no optics, it’s sad I have to say that) as an M16A1. But it’s (more or less) a shortened M16A2/A4 (flattop, of course) which was heavier than the M16A1. The old Colt model 653 is more or less an M16A1 shortened to have the collapsible stock and 14.5″ barrel, and it is as light as you would expect.

        Agreed about the weight/balance issues of this. And entirely too much recoil. I don’t like it, but I’m sure someone will be along to tell me how great this will be.

      • RSG

        That’s part of the extraction system, I believe. There’s a locking mechanism and spring release that applies force to drive the rimless case out of the rifle. Someone can correct me if I’m wrong.

    • TheNotoriousIUD

      Came to ask the same question. Is that a glove box?

      • Parvusimperator

        As I understand it, the cased telescoped polymer rounds have to be push fed/extracted. If you look at the article/report Nathaniel linked above, you can see that the cased telescoped rounds lack any kind of rim for an extractor claw to hook onto.
        So, presuming the design hasn’t changed since the last time I looked at LSAT, there’s a vertically-sliding breach assembly to facilitate the push feeding and extracting. At one time I had found a diagram, I’ll see if I can find it again.

        • TheNotoriousIUD

          Thats interesting, id like to see that if you can find it.
          Im no expert but I would think more moving parts would be a negative for a battle rifle.

          • ostiariusalpha

            There are basically two main moving parts; the feeder/ejector, and the chamber. On an AR-15, you have a rotating bolt and a reciprocating bolt carrier, which makes for the same amount of moving parts. On the CT carbine, the feed pusher does the same work as the AR’s extractor claw and ejector plunger, so those two points of failure are eliminated. That said, this thing could definitely use some serious design refinements to get rid of that bulk in front of the magwell.

          • Giolli Joker

            That might have been the diagram of the Steyr ACR, employing a similar concept.

          • Joshua

            it’s not. The chamber is rotated via the carrier/oprod akin to how the AK carrier rotates the bolt.

            Also the push feed system is far more reliable than rearward extraction of cases that have to obturate against the chamber.

            Timing is far more forgiving and you will practically never have a failure to extract with this system.

  • AtomicYeti

    4 kilos as a prototype is ok, They will trim the weight down as they go along hopefully. 4.7 loaded without optic is like a G3 😀 Waiting for test results.

    • Maybe, but the trend is for prototypes to get heavier during development, not lighter.

  • micmac80

    123g bullet at 3000fps that is near .260rem balistics , way to much kick for a .556 replacment and balistics closer to 300WM than 7.62×51

    • DIR911911 .

      7.62 hits over 2700 fps with a 147 grain bullet , so I’m guessing if we brought that weight down 30grains those velocities would line right up.

      • It’s pretty much in line with the new M80A1, which is a 130gr @ about 3,000fps.

        However with a 6.5 projectile, this likely has a higher BC and flatter trajectory.

      • Vitor Roma

        The 6.5 has way better BC, shoots much flatter. Makes the 7.62×51 feel like 7.62×39.

  • Raginzerker

    I mean it seems like a step in the right direction, it’s new technology so you can’t expect it to be perfect.

  • 11b

    Wait, so the rifle is heavier than a standard M4 and fires heavier bullet (6.5 vs 5.56). Where are the weight savings? Add an optic and a laser like most issued weapons and you’re probably carrying as much weight.

    • Landiss

      The ammo weighs less.

      • DIR911911 .

        if the ammo weighs less but the gun is slightly heavier that means the soldier carries more weight for longer since your ammo gets used up and lighter as you shoot.

      • The ammo weighs 30% more than 5.56.

    • TheUnspoken

      It seems like the weight savings talk should be in comparison to a .308 gun rather than the m4, otherwise you are getting more weight and less capacity, so the only discussion point is a potentially more powerful round.

      • Giolli Joker

        Yep… and against a .58 cal musket the rifle is much smaller and portable. 🙂

  • How much weight could they knock off it by replacing all the built-in tactical cheese graters with a negative space mounting system like M-LOK or that other one nobody likes anymore?

    • Ebby123

      An ounce or three. Aluminum doesn’t really weight that much. Now a slimmer rail with thinner walls and negative rail mounts could shave 5 or 6 ounces I’d wager.

      Still, to cut real weight, you’ve gotta cut steel.

    • Marvinator

      That’s gonna take another 7 years. (optimal) 12(threshold)

    • CavScout

      K, but KAC will have to make the handguards so they aren’t the fragile ones most people are making. Also, I haven’t noticed anything in the way of optics mounting in MLOK or Keymod. Until that gets sorted, soldiers don’t want two different QD mounting methods on each weapon. Questionable whether either is strong enough, or retains stuff well enough. Don’t need a PEQ to randomly fall off from a quick pinch. I haven’t even seen any locking lever mounts in use.

      • CZFan

        That is a BS excuse, we used cheap crap plastic handguards for ever and them “breaking” was not an issue.

        Besides the KAC RAS systems on the M16 and M4 just clip in with the delta ring and handguard cap, they are not secure for optics mounting either.
        Thats why NV has the top strap, and even without it a front mounting NV does not need to be rock solid to “work” obviously it would be better but the KAC does not offer that anyway.

        There are TONS of commercial rails that would be a vast improvement over the KAC RAS.

        Any rail that free floats would be an improvement, Troy Alpha rails clamp right to the Original barrel nut and are bullet proof, they are slimmer, lighter, and 100% modular with a rock solid top rail for optics.

        Yanking the KAC rails off most military guns and replacing them with Magpul Furniture would be a vast improvement, and cut rail weight by over %50 for M4’s and more for the M16.

        Not only that but getting all that weight off the barrel would help with accuracy especially during extended firing, even if you dont go to a free float system.

  • Liberals and Communists trigge

    Now that is an interesting rifle.

    • DIR911911 .

      how? it’s as heavy as most 308 rifles and barely shoots a little faster with a lighter bullet?

      • ostiariusalpha

        Whoa there, this isn’t a production model, it’s not even a prototype. Also, I would think you might have been reading enough on this blog to have at least a little familiarity with the concepts of ballistic coefficient and retained energy. The advantages of the .264 caliber projectile over a .308 should be obvious.

      • Liberals and Communists trigge

        In case you havent noticed it is one of the few guns that shoot plastic cased bullets.

  • DIR911911 .

    took all the way till the last sentence to say what I was thinking as soon as i read those specs , m14. hell, sounds like my dpms falls in the same category as well. you could mimic this performance from a 7.62×51 just by loading up a slightly lighter bullet? what are the “advantages” if it weighs and shoots the same as what you already have access to?

    • iksnilol

      Much lighter ammo?

  • aka_mythos

    What does that portion of lower reciever ahead of the magazine well house? It seems superfluous.

    • It houses the feeding and ejection mechanism.

      • aka_mythos

        That makes me curious how that mechanism cycles.

        • I am guessing vertically sliding chamber, but I don’t know.

          • aka_mythos

            I’m sure you have a list of things to write articles about… please consider adding “how this works” to that list, even if its sometime before you have the chance.

          • I haven’t added to it in a while, but I have a series on operating mechanisms in general, if that’s what you mean:


            If you mean CTA guns specifically, that would be trickier, as I’d have to make SolidWorks models to explain everything. Maybe.

          • aka_mythos

            I’ve really enjoyed the different technical articles you’ve done. The CTA gun, there is much to read on it that’s why I want to see more. Take your time, no rush.

          • Monty01

            Please do explain how CTSAS technology works. The viability of this concept probably hinges on the simplicity /reliability / weight of the operating me hanism versus legacy systems.

  • The 7.62×51 weighs 25 grams.

    7.62×39 weighs 18.2 grams.

    The new 6.5 PCT weighs 15.2 grams.

    So you have a round that’s a good deal lighter than 7.62×39, that will outperform 7.62×51 due to higher BC of 6.5 projectile, and has 2,458 ft/lbs of energy. Very cool.

    • iksnilol

      Your quoted weight for 7.62×39 is very wrong.

      brass cased weighs about 17 grams, steel cased about 16 grams.

      • Proving once again that I shouldn’t put as much faith in Wikipedia as I do 😉

    • Recoil? Flash? Blast? How can we expect these qualities to be affected by such a round?

      Plus, if they really are pushing that as a universal round, in order to maintain weight parity with the current system, 1,800 rounds in the platoon need to be left at home. Is that worth it?

      • The 6.5 brings up quite a few questions, and the answers to those determine really whether this is a step forward, or back to the future.

        To begin, will it indeed be a “universal cartridge,” or is it just a superb replacement for the 7.62×51? It’s obviously an awesome upgrade to 7.62×51 in terms of weight, and likely ballistics as well, depending on the BC of the 123gr 6.5.

        If it’s a replacement for 5.56 as well, the question is, do the primary benefits of 5.56 still matter with current military doctrine? The 5.56 was designed a) to allow the soldier to carry far more ammo then they could with 7.62×51, which 6.5 PCT also offers, and b) to offer low recoil controllability in full auto.

        It’s obviously not going to be controllable in a carbine on FA, but that brings up the question, does that matter? Given modern optics, it seems that full auto rifle fire has been largely abandoned by the US military – notably, in almost all of the training videos of the Marine’s M27 “automatic rifle,” even it is being fired in semi auto.

        If current doctrine and the future is semi auto rifle fire using optics, the question is, will the added recoil make it uncontrollable? Historically, millions of troops have managed to handle semi auto .30-06 Garand’s and 7.62×51 FAL’s. In the modern era, we’ve seen some SF troops using 13″ SCAR 17’s in the CQB role. So given a decently trained troop, it’s likely to be fine in semi auto.

        Decently trained troop brings up the most interesting question of all, which is, what is the future of infantry combat for the US? Will we once again see a mass mobilization of troops as we did in the Iraq war, with hundreds of thousands of boots on the ground? Or does the future of infantry fighting more closely resemble the broader GWOT, with small SF teams and the selective deployment of Rangers and Marines?

        Given the trend towards semi auto rifle fire and the use of “low footprint” elite troop deployments, I think the 6.5 PCS would make a great step up over 5.56, or a 5.56 PCS.

        In the role of the carbine, 6.5 PCS offers extended range for suppressing and engaging targets armed with 7.62x54r, it offers superior barrier and armor penetration at all ranges, and if the M80A1 gel test is a predictor, it would be absolutely deadly as a CQB round. That to me would be worth a bit more recoil in semi auto and a few grams heavier loadout. I would however want to see a 30rd mag developed.

        As for the role of SAW (which is where I assume most of the 1,800 rounds lost per platoon is made up) the question is, would you prefer a M249, or a PKM in the role of squad LMG? The 6.5 PCS offers the range and power of the PKM, but with potentially 40% more ammo being able to be carried over 7.62x54r. Short of repelling a human wave attack, that seems well worth the reduction in overall cartridges carried.

        • lostintranslation

          Agree…..aimed semi-auto (in conjunction with magnifying and electronic optics), rather than; ‘spray and pray.’

        • Quest

          Aimed semi auto at range (still longer reaiming/ slower follow up shoots). But in closer quarters or ambushes its dumb… low capacity with far too high unneeded Recoil. Turns hit propability way down.

          If your sitting on a open battlefield its ok (and even for that still VERRY far from any perfect).

          But you will just get shot by mortar etc, without exposing enemys, and if they present the smallest possible target, supress you and have cover. Aiming error, Trajectory and time of flight alone makes bullets in general hard to use at this range under such conditions.

          While in Urban combat where the direct Rifle performance often shows itself, this round is a CLEAR step backwards. And a pure shame for the time we live in. Just waisted potential.

        • majorrod

          Totally reject your premise that semi-auto is a trend. There are still PLENTY of fully automatic weapons in an ODA which is not a predictor of what the conventional side looks like who are still carrying their fully automatic weapons.

          You also can’t assume we are going to be fighting the same type of enemy we have for the last 15 years. An enemy that typically doesn’t sit and fight requiring fire and maneuver facilitated by superior firepower delivered by automatic weapons.

      • majorrod

        is that 1800 rounds taking into account the 40% drop in weight of telescoped ammo?

        • Quest

          Yes he did serval calculations and posts about it. In the analysis part 1 and 2.

  • iksnilol

    Would be good replacement for the M14.

    • randomswede

      Cue the hate and tongue-in-cheek, but what modern military rifle isn’t.

      • iksnilol

        I mean, a Mosin is a decent replacement for the M14.

        • LCON

          I am trying to think of a funy rebuke of that… but My brain cannot Comprehend that that statement was even made.

          • iksnilol

            You cannot rebuke the truth is what’s the issue.

          • NukeItFromOrbit

            I’m hoping that was a joke from iksnilol.

  • LazyReader

    The weapon weighs 8.7 lbs empty? One mag plus all the stuff you add on (be it soldier or accessory lover ^_^)

    Let’s see…
    -IR viewer
    -rail covers
    -Grenade Launcher (LET FREEDOM RING)
    thats……12+ pounds probably

    • Ebby123

      Don’t read into it too much. Prototypes are almost always built like tanks.

      Most of the weight savings comes after function is perfected, during the optimization process.

      • Huh? The trend is almost always towards weight increase during development, not decrease.

        • Ebby123

          Are we talking first functioning prototype, or just a mock-up?

          • This is a mockup, but I am certain they have CAD models of the weapon.

  • gunsandrockets

    Seems like a reasonable cartridge for a squad LMG or DMR. Whether it’s best for a general issue rifle/carbine depends on how much and what type of emphasis you want to put on individual weapons; does the rifle tail wag the MG dog? And how vital is individual full-auto fire?

  • marine6680

    This is a non-functional display/model mock-up of a rifle, that doesn’t even have a fully realized prototype.

    Meaning we can’t go on this model as a weight reference.

    And until they have a functional design… And then have it to a finalized state, we still can’t. It’s not uncommon for prototypes to weigh more than the final design, as they refine things.

    • Ebby123

      Its all but a guarantee that the final product will be lighter than the prototype.

      Injection molded parts replace aluminum machined prototypes, castings and forgings with more optimized volumes replace crude billet mock-ups, and materials are optimized.

      Yeah, I wouldn’t read into the system weight too much right now.

    • Weight estimates this early in the design stage should actually be very reliable, given the use of CAD models in development.

      Keeping in mind that the development trend for virtually every weapon in history has been to get heavier over time, not lighter, I am not optimistic.

  • Vitor Roma

    Given the range and power, is much more of a replacement for the 7.62×51. Good, time to accept the swedes were right all along.

  • Mack

    I see this more of a replacement for the SASS and not infantry rifle.

  • Anonymoose

    This cartridge they’re touting would be superior to 6.5 Swedish, and at that weight it would be better than a Mk14 or an M110 for a DMR role, but 16″ Mk17 is still lighter. This could be our next general-issue DMR, even if they don’t shave off any more weight.

  • ArjunaKunti

    Switching to relatively lightweight cased telescoped cartridges offer a great opportunity to change the caliber system too:
    -4.6-5.7 mm for PDW/pistol/mini assault rifle role
    -6.5 mm for DMR/LMG role
    -8.6-9 mm for heavy MG and sniper role.

  • forrest1985

    Cleary a DMR replacement, but the “carbine” mentions will cause confusion I imagine. No way this is an M4 replacement, looks at the stats. Loaded it weighs more than an M4 with 10 less rounds….but,again when you add weight of bipods/scopes etc… weight wise its not much of a saving vs existing DMRs and adds an extra catridge into the supply chain… As Nathaniel says, prototypes tend to be lighter than finished article.

    • Joshua

      The idea is to have one round for all needs.

      A 6.5 CTA LMG is far superior to any current 7.62 LMG we have, and the 6.5 CTA carbine could replace all 5.56 carbines and 7.62 DMR’s, giving us one round for every roll.

      Also this is not a working prototype, however considering the original design carbine was a huge blocky beast and they now how a system slightly heavier than the M4 is huge.

      I have a feeling the prototype model we see next year will be as light as the M4 and offer far greater capability.

      • Quest

        This kind of 6.5CT can NOT be effectivly used in a Carbine without verry huge performance potential waist.

  • LazyReader

    Always thought the rifle of the future would shoot solid at 3,000 meters per second, I’ve been lied to by Bungie

    • mechamaster

      Maybe in “First-space war”, the place where the railgun and gauss-rifle will shine. Because there are no sensitive gun propellant, and in the microgravity, big bulky gun doesn’t weight too much ?

  • NukeItFromOrbit

    Is it me or have the tags been getting progressively more snarky as time goes on?

    I for one think such a caliber has a lot of potential to replace existing 7.62x51mm weapon systems. Replacing 5.56mm however? A bit too heavy/powerful for that.

    • Quest

      Absolutly correct.

  • Camo_Steve

    We went 5.56 for a reason.
    -Reduced recoil
    -Carry more rounds
    -Adequate job killing guys 300m or less. (which is where the overwhelming majority of engagements will occur for infantry.)

    This new round is a step backwards for infantrymen.
    -More weight
    -Less rounds
    -3x the recoil
    -Extra range you will almost never use.

    They should have made a case-telescoped 5.56 version of the rifle.

    • Quest

      Verry good analyses. Youre one of the people who actually got it.

      And actually you can get the range with far less energy. Its kinda like they said “Mhh lets take a 123grain projectile 6.5mm (123grain isnt really realistic for modern EPR anyways), and…. now we have to get it to 1200yard supersonic… Which takes incredible energy with this far to fat and fully uneeded heavy bullet.

      The other way around is the right way to do. Supersonic Range-> Energy Level -> calculating -> finding the best suitable caliber.

    • iksnilol

      Compare it to .308.

      To be honest, they should make a 4.5mm version of it as a replacement for 5.56

      • Arathar

        I calculated a lot and 4.5 isnt ideal. The sweet spot is between 5mm and 5.5mm. But i dont want to get to specific.

  • A Fascist Corgi

    My best guess is that they’re secretly developing some kind of new technology which greatly enhances accuracy. If not, then I still think that it would make more sense to simply upgrade to the 6.5 Grendel round or something close to it.

    • OnTheOP

      Guided smart small-arms kinetic energy bullets are… how to put this kindly… uh, incredibly retarded. They would cost a fortune, and offer only marginal improvement, since they would still need a guidance system capable of differentiating the target from the background. Trackingpoint-type systems are ok, but are really only useful against unaware targets, as the engagement sequence takes entirely too long, so by the time you acquire, lase, shift aimpoint, and fire, the target is already back down and out of sight. Not to mention that at normal engagement distances, modern projectiles have such flat trajectories that there’s no real need for fancy fire-control calculation of lead and hold-off; the shift in point of aim for those factors at under 300 meters is much smaller than the size of the target anyway.

      No, the new technology is ABHE (airburst HE), like that found in the M25 CDTE. Greatly improves single-shot probability of incapacitation, is forgiving of targeting and laying errors, and gives defilade target engagement (targets behind cover), area-effect and anti-material capability to a rifleman. They just need to bring weight down a bit, get the magazine capacity up to the 10-15 mark, and develop flechette AP/ canister rounds for in-close use.

  • Monty01

    This weapon concept introduces three new technologies:
    1. A new calibre
    2. A new cartridge type
    3. A new operating mechanism

    It will require a totally new manufacturing infrastructure plus significant investment to reliably mass produce both weapons and ammunition. The risks seem enormous and I wonder if they outweigh the benefits. Someone described polymer cased-telescoped ammunition as: “Like designing a better sail instead of a motor boat.” I thought that was a good analogy. But, it is an interesting development and I think it should be tested further to assess its battlefield viability.

    I agree that a 6.5 mm / .264 projectile fired at 3,000 fps / 914 mps weighing 123 grains / 8 grams is likely to be too heavy and have too much recoil. We need only to match 7.62 mm at 1,000 metres, not to far exceed it.

    A highly aerodynamic 6.5 mm / .264 bullet weighing 108 grains / 7 grams fired at 2700 fps/ 822 mps would somewhat reduce cartridge weight and recoil while still matching 7.62 mm NATO. Or, a 6.35 mm / .250 bullet weighing 92 grains / 6 grams fired at a similar velocity would reduce weight and recoil further. We really don’t need to go go much bigger than 5.56 mm to achieve a worthwhile increase in performance – including a very good capability beyond 600 metres in machine guns – even if we don’t quite match the 7.62 mm M80A1 EPR.

    I genuinely believe that NATO needs to move beyond 5.56 mm and that an efficient intermediate caliber between 6 and 7 mm could be a great replacement. But we have to avoid reintroducing the very same disadvantages that led to 5.56 mm replacing 7.62 mm back in 1979!

    Ultimately, the challenge of a next generation system, assuming that the technology to produce a phased plasma weapon in the 40 watt range remains beyond our grasp for the foreseeable future, is to deliver a projectile and delivery mechanism with sufficient energy to defeat the specified target at the required range. If that’s CTSAS or a polymer version of conventional brass-cases ammunition, it doesn’t matter. What matters is total system reliability in the hands of our warfighters (the rough men who stand ready to do violence on our behalf so that we may sleep soundly in our beds).

    • Quest

      1. Not a new caliber (and a rather bad one for rifles and carbines)

      2. Not a new cartridge

      3. Not a new (exist since 3decades) and in this version also VERRY poorly executed operating mechanism.

      Further your analysis is correct. Its too heavy and thick.

      But no 6-7 isnt that much a great way for rifles and carbines, you only get slow projectiles, bad trajectorys/ or too high recoil with those bullets at adequat velocity. No improvement in actual performance, which would be hit propability.

  • Quest

    Overall yes. BUT “fielding body armor” together with the need for “penetration” isnt really that sencefull.

    Lvl4 plates hold 7.62×63 Tungstencarbid as minimum. Ive seen it holding .338LapuaMagnum (ofccourse with a certain deformation).

    So direct penetration would not be possible with a practical standart Rifle/Carbine. In therms of such high armor plates, direct zones of incapacitation/death are head, neck, arms, legs.

    A mid energy (2000-2400J) projectile will do a much better job in therms of % hit propability of such zones. You have more magazin capacity, far less recoil, much faster follow up shots, therefor less stress, overall lighter rounds.
    This including the event that the opponents body is presented in the first place.

    Which is really uncommon, that leads to the next point. Too much recoil, less magazin capacity, will sicnificantly drop performance, and % hit propability.
    If the opponent as usual presents an extremly small target, not just that the projectile energy makes no diffrence at impact due to the highly vital spot (head/neck) presented. But also due to the recoil follow up shots will become problematic and slow, resulting in a huge % hit propability drop, even less reliable under such stress, which could get increased even more with such recoil when the Rifleman cant make fast enough accurate shots and with this physically hindering/limiting him starting to fear to get hit in this situation. With less magazin capacity you not just need to reload more often but the real critical part would be the reaiming.

    And more weight than brass cased 5.56×45, by far isnt something we should look for in the future.

  • I would be surprised if the carbine used a swinging chamber. It’s a good idea for a belt-fed, not so great for a mag-fed carbine.

    • majorrod

      I have no idea but it’s one of those cases where we know you can’t bring the mountain to Mohamed so we have to look at another approach. There’s no rim to extract the empty composite case from the chamber so the chamber likely has to come out of battery. Swing, fall, rotate?

  • For the record, recoil makes a big difference in semi-auto fire, not just full auto fire. Even the difference between a 5.56mm rifle and the same rifle with a muzzle brake can be a large advantage. So saying “well, full auto isn’t used that much, so we can have as much power as we want and no worry about recoil” isn’t really accurate. In the 0-300m range band, there is a huge difference between even weapons that both have low recoil levels.

    Plus, while full auto fire is not used a majority of the time, it is on occasion needed. Saying that “well, we can discount full auto fire characteristics because it’s used a tenth of the time semi auto fire is” is sort of like saying “well, we can discount aimed fired, since aimed fire is used a tenth of the time area fire is”. All of these capabilities are important, and must be designed into the system.

    • I’m not saying that we can have an infinitely powerful carbine cartridge, but rather that, given the dominance of semi auto fire within all branches of the US military, 6.5 should not prove to be uncontrollable.

      Millions of US Soldiers shot Garand’s to good effect in WW2 and Korea. For most of the post-war years, Europe and Latin America ran FAL’s and G3’s. Turkey, Cyprus, and quite few others are still running G3’s. Some modern SF teams have been employing the SCAR 17, including in the CQB role.

      The point being that .30 caliber rifles firing 147-175gr projectiles have not proven uncontrollable in Semi Auto.

      The 6.5 fires a 123gr projectile, so its recoil will be slightly less then 7.62×51, and will (bordering on complete incompetence) have better ergonomics than the battle rifles of old. The use of a suppressor will likely further reduce the recoil.

      When you combine that with the increasing reliance on small footprint, elite forces being the primary trigger pullers for future conflicts, who spend significantly more time training, it doesn’t seem like 6.5 would be too much cartridge for them to handle.

      Given that the vast majority of full auto fire is handled by the squad automatic weapon, the loss of full auto in the carbine is well worth the tremendous increase in range, barrier penetration, and lethality. Especially given the tremendous improvements in optics.

      The other flip side is that a LSAT 5.56 clone is not really worth the massive hassle of a complete rearmament.

      Assuming a 50% reduction in weight for 5.56 LSAT, and a standard combat loadout of 7 magazines, that’s saving 3.5lbs by switching to LSAT (assuming that the new rifle weighs the same as the M4A1, a big if.) A 10 magazine loadout would be 5lb weight saved.

      In the role of the SAW, 200 rd’s of 5.56 in the plastic box is listed as 6.92lbs; 600 round loadout being 20.7lbs. So LSAT would save 10.35 lbs. A slightly larger weight savings, but on the other hand, simply ditching the M249 for the Ultimax would save 6lbs without any change in cartridge.

      Meanwhile, given the “100lbs of lightweight gear” phenomenon, this saved weight would likely be replaced with some other tool or gadget, resulting in no new cumulative “lightening the load” for the soldier.

      If 5.56 performance is indeed optimal, then we should just stick with the 5.56, and spend the couple billion LSAT would cost on training and advanced smart optics / electronically fired trigger systems to improve the hit rate.

      Conversely, if the LSAT program is to move forward, it has to produce a substantial improvement in performance over 5.56, beyond saving a few pounds per loadout.

      Given a magic wand, and you were in charge of the LSAT program, what cartridge/ballistics would you put forth for the program?

      • Quest

        5.56×45 performance is not optimal. But just because its terrible nose ogive, OAL, etc, etc, etc, etc.

        With new Rifles recoil will get reduced, 5.56 therefor can get more velocity and bc. And become an incredible high performing infantery round.
        With a well optimized 5.56 you can reach 1200y supersonic, and when calculating it against a more heavy projectile but the same energy it actually needs less bc due to the flatter trajectory, and therefor less actual direct travel distance trough air.

        Due to KE=1/2m x v² in relation to p=m x v it have less recoil.

        And higher KE/mm² due to the higher speed and smaller diameter.
        Also better angle of attack at range for better peneration and less drag in air….
        Also the incredible advantage in therms of trajectory.

        6.5 sounds nice, but its just too fat to give it adequat speed at maximum bc, without bringing energy, recoil, blast, pressure, and low magazin capacity to an unlogical level.

        • That sounds very interesting, can you describe in more detail what type of 5.56 is supersonic at 1200 yards, in terms of bullet and muzzle velocity? And is that type of bullet shape compatible with the M855A1-style steel tip fragmenting design?

          There’s a 6.8spc wildcat that’s necked down to .224, some are hitting 3,300 w/ 77gr projectiles. That’s more in line with what I would have preferred for the LSAT carbine.

          • Nameless Quest

            Ofcourse not. Just wait. Sooner or later you will hear about it again.
            I have other options to futher sicnificantly increase aerodynamic, and make it even far more efficient.
            And yes ofcourse its EPR, also our new APR1, and hAPR1 /APR2, hAPR2.
            And these are only backups, not nearly the slightest bit close to the main Apex Round.

            Just a simple question, due to the lack of the huge heavy bolt carrier it has less movement, felt recoil, etc etc. So we can go over 5.56×45 ~1800J without increasing Recoil. What Energy would you prefer for a Rifle/Carbine, 2000J 2100J 2200J 2300J 2400J ?

          • Energy doesn’t really matter as much as velocity, as I believe that is the primary factor involved in most rifle projectiles fragmenting or expanding. 2000fps is the fragmentation threshold for the 77gr SMK. I have not heard what the fragmentation velocity for the new M855A1 is, only that it is much lower than the M855. Let’s assume 2,000fps as well?

            I’d ideally like to see any new round doing 2,000fps at 500 yards.

          • Nameless Quest

            Ive heard about tests were M855A1 EPR was reliable segmenting at 600m. And even if not, its rather long and tumbling will still makes wounds that wont let the opponent furter happly advance hundrets of meters. And area of hit is most important at this range anyways. But for arms and legs its better than tumbling, icepicks would not incapacitate reliably, and heal quick. Ive seen a guy got shot by 7.62×39 M43 trough the arm without hitting bone. He was happy and just put a bit cloth over it, than further helped his buddys.

            Also ive seen a direct test of M80A1 EPR simulated to 450m it fragmented instantly without a neck. 1929fps and remember M855A1 EPR break up more easy.
            Therefore with a new truly modern SCHV, segmenting/fragmenting over 500m is verry verry easy to achive.

          • Nameless Quest

            *I meant fragmenting is better than tumbling at arms and legs due to how thin they are and chance of icepick of tumbling bullets in this area.


          • Hypothetically though, is there a .224 that would be going 1600-2000fps at 500?

          • Nameless Quest

            haha ofcourse, 2000fps with an EPR at 500m is no big deal
            Doesnt even require our more advanced APR or hAPR, which would hold such velocity at much further ranges.

          • What would be the weight and start velocity for it be going 2,000 at 500?

          • Nameless Quest

            I just wanted to correct you about your toughts on 3333Joule 6.5CT, also wanted to bring a new and diffrent view on the topic. But not giving out details, i dont know you yet. Sorry.
            If you still want to talk about the topic in general im open for conversations. If you have G+ i add you.
            Have a great day.

    • Kivaari

      I get ridiculed when I pointed out that the recoil on an M4 is enough to cause problems. Even rapid fire with an M4 at 100 yds needs time for the gun to settle down.

  • Umberto

    How long is the barrel? I heard there were some savings in space coming from the different mechanism, any idea/stats?

  • TW

    I hope as the weapon gets lighter and a heck of a lot better looking as time goes on. Right now it looks in unergonomic as heck.