New Cartridge Developments and Implications for Dismounted Infantry Soldiers

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  • stanc
    Banned
    • Apr 2011
    • 3430

    #16
    Originally posted by JASmith View Post
    I get 80 grains when scaling a 62 grain bullet from .224" to .244"
    Yeah, that's what I calculated, too. But, since it was about 0500 when I did it, I wasn't 100% sure I figured right.
    The Berger 115 gr VLD bullet has a bullet of length = 1.365 inches. We can get to about 100 gr by stretching the scaled M855 to this length.
    That would result in 5.6 L/D. Isn't 5.0 considered the max practical L/D?

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    • stanc
      Banned
      • Apr 2011
      • 3430

      #17
      Originally posted by JWH View Post
      Thinking about Liberty Ammunitions T3 copper body/steel tip bullets.
      First I've heard of this, John. Tried googling, but got nothing. Can you link?
      I'd like to explore the concept of a 6.5mm T3 with a lighter bullet for ARs and a heavier bullet for LMGs.
      While having heavy bullets in linked machine gun ammo and light bullets in stripper clips could be done in theory, the reality is it goes against long-standard practice in both US and UK armies.
      Thoughts on the Knight's Armament Stoner LMG? It has constant recoil. Convert to 65G as a proof of concept?
      Don't know enough about it to comment, except to say that (IMO) it ought to be as good as any 5.56 LMG for conversion to 6.5 Grendel. Got metallic links?
      Still think 6mm is too similar to 5.56 to change.
      You may well be right. I'm no longer so sure about it, myself.
      I maintain that 6.5 very nicely splits the difference between 5.56 and 7.62 and that the extra bullet mass counts for . . . something! (Seriously, I'm thinking construction material barrier penetration.)
      Yeah, bullet mass is important to defeat some materials.

      Comment

      • stanc
        Banned
        • Apr 2011
        • 3430

        #18
        Originally posted by LRRPF52 View Post
        I would also stipulate that the new projectile meet or exceed 7.62 NATO M80 lethality out to 600m, and exceed its penetration of standardized mediums at 500m. I'm not sure how lethality can be measured for developmental testing, since there is no scientific baseline to establish it...
        The only way I can think of is by comparing gel tests, for equal or better wound trauma.
        The design I shared with a company in North Carolina 8 years ago peaked their interest, but I never followed up with it. It basically uses some ideas from the Russian improved 5.45mm projectile named 7N10, with a stacked cone narrow rod of tungsten or hardened steel, with a lead filler, and a uniquely shaped internal tip for the lead with a hollow nose cavity, and a thin full metal jacket with cannelure. This was for a 5.56 project, but the same thing could be applied to any larger caliber of course.
        Unfortunately, use of lead and tungsten rule out such a design.
        I would like to approach the new cartridge specs from 1) on-target performance, 2) Trajectory requirements, and 3) weight limitation constraint parameters. Then look at projectile dimensions, cartridge geometry, propellants, and links.

        I think we can all agree that 6mm is the bare minimum in acceptable diameter to get the length/weight we need, and 7mm is probably the maximum to keep weight and recoil down, while finding the best aero-dynamic performance from a mass-produced projectile.

        6mm offers the best terms in recoil & weight reduction and aerodynamics simultaneously, and possibly penetration and wound effects if it can yaw in tissue and fly straight through the standardized barrier mediums. It also would be easy to get to velocity, but could introduce over-bore problems for throat/barrel life.

        The 6.5 seems to alleviate a lot of the potential drawbacks of 6mm, but poses significant challenges with regards to case capacity getting it to 2800 fps.

        Do we all concur on this?
        Sounds good to me. What do you have in mind for item number 1) on-target performance?
        Last edited by stanc; 05-17-2011, 07:59 PM.

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        • #19
          John,

          I understand your perspective. I've noticed that it's really easy for us to tunnel-in on the M4/5.56 caliber topic when wearing our civilian hats since we don't commonly own & shoot belt-fed machineguns, but from the end-user perspective in an Infantry Squad, the M4 is the strong link in maneuverability and close quarters out to 100m engagements. The riflemen sometimes don't even bother competing with the SAW and 240 gunners when distant targets are being engaged with the pigs, 203's, and now DMR's.

          The 5.56 is great for shooting people within 100m and often gives sufficient target effects out to 450m, being that good hits on target take the guy out of the fight. Would I like to throw a switch and have the Grendel at 300m plus? Yes, but not at the sacrifice of the other end of the spectrum, which a light assault rifle load could actually address, but then we're back to the distance limitation again, and since we won't be swapping out linked ammo and mag-fed ammo as a rule, we effectively would be back to a two-caliber system, with less mag capacity for my door-kickers, alley cats, and trench sweepers, while every other threat assault rifle will have at least a 30rd mag.

          One thing I would hate to see lost is the mag capacity in the M4 30rd mag profile/weight, and the handling and blast characteristics in close quarters. Running my 16" Grendel with 100gr NBT's has shown me how little recoil can be achieved with it, but there's still the issue of mag capacity/mag profile/and added weight. Let's just say that most dismounted small units that use light infantry tactics around the world who also have a choice of weapons-even outside their country's service rifle, almost unanimously choose the M4A1 in 5.56 NATO, or a similar carbine based on the M16 family of weapons, and you hear very little complaints from them about 5.56 NATO in a carbine.

          The big limiting systems right now are the SAW and the M240. They are what is screaming, "Fix me! Fix me!" I have been tracking the KAC LMG since its introduction, as well as some of the background weapons and ideas it sprang from, and that is an awesome little LMG. I don't know why Knight's isn't pushing it harder. History says that the "new" Auto Rifleman approach using the coffin mags will fail, although I hope that I'm wrong, since that is what the Marines are going with for a replacement/augmentation for the SAW. A lot of that system's success will rest solely on the shoulders of those 60rd mags from Surefire and Magpul, and I hope they can pull it off...really. Once a coffin mag goes Tango Uniform, you're screwed, since the ammo can often only be retrieved by removing the floor plate. We'll see how those mags turn out soon enough.

          What requires the move away from a package like the KAC LMG is that it has a conventional barrel arrangement, which will not be long enough to support a caliber that will exceed the M80/7.62 ballistics. Maybe 6.5 Grendel in the KAC LMG could duplicate 7.62 NATO out to 600m from the short barrel, but that would be a stretch I think given the limitation of needing mass-produced bullets, not Scenars, VLD's, or SMK's. The main things the KAC LMG have going for it are lightweight, constant recoil, and low profile. If it were introduced, you would see guys actually wanting to carry it, versus the dread of humping the SAW.

          In order to duplicate the low-profile of such an LMG, and match or exceed 7.62 NATO ballistics past 600m, a longer barrel is needed, which means it needs to be a bullpup LMG. With a pulsed-stage propellant, it's theoretically possible to get the Grendel to increase MV with heavier bullets, and not exceed pressure limits in current brass, but it's only theoretical right now. That propellant would revolutionize metallic-cased ammunition technology, but remains an idea currently. Even if I had the fully-funded R&D infrastructure to pursue it, it might end up being a flop, and would most likely entail some unforeseen challenges that could spell its doom.

          For the Grendel to be a viable replacement for 7.62, I think it needs to push at least a 130gr, if not 140gr FMJ at 2800 fps, which we all would never try right now, even with a bolt gun. I'm not even sure my .260 Rem could do that safely in my gas gun, as I'm running with light pressure signs pushing the 123 Scenars and 130gr VLD's currently.

          I'm basically looking for 6.5 Swede ballistics with the 140's. I wouldn't want to enter and clear a room/building with that type of a cartridge in my carbines normally, for a bunch of obvious reasons, but my gunners would do well supporting the riflemen in MOUT with that system. This is one of the areas where 5.56 makes its money, and does it well, and the close-in barrier defeat characteristics of something like a 6.5 Swede would really give soldiers a tangible sense of destructive.suppressive power over the SAW, while leaving the ungainly 240 in the dust.

          LRRPF52

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          • #20
            Sounds reasonable to me. What do you have in mind for item 1) on-target performance?
            On-target performance would address human targets first. Since every person reacts to projectile injuries in different ways, I would like to see an upgraded standard to ballistic gelatin representing:

            * Tissue compartmentalization
            * Bone structures
            * Body heat
            * Clothing/Equipment
            * Skin and sinew
            * Anatomical orientation

            That equals a major cost increase in gel testing, as you would have to build a semi human replica with an anatomical skeleton-at least the torso, and compartmentalize organ chambers, the abdomen, etc. If that was done, you could more reasonably say, this projectile from this aspect will probably do x, y, and z. If it misses the ribs but is within probable path of the left lateral spine between T4 and T6, the likelihood of lower extremity paralysis is 65% higher. If it hits the sternum from a 15% oblique frontal shot from the target's left side, his right lung will suffer this type of a wound profile, given that he was wearing his chest harness with the straps loosened, exposing that area more. If the projectile hits this landmark on a fully-loaded Bakelite AKM magazine from a 30 degree angle in a canvas chest harness and then passes through an M-65 field jacket, chances of vital zone penetration are reduced ( )%.

            Most of us would postulate that long, high-sectional density bullets would be superior to the currently available projectiles in such tests, but that has to be demonstrated. I would also suggest simulating different types of ballistic gel density to represent the muscle and organ tissue density as close to mean as possible for different areas of the world, since that is a factor in wound ballistics.

            That answer may be too long, complicated, and expensive, but I don't know what else to say, since we are of a culture that thankfully has moral standards that preclude us from conducting live tissue training on various human subjects, unlike some of the other governments in the world.

            Barrier target performance would include defeating foreign trends in armor, common construction materials for walls and structures, light-skinned military vehicles (will this be able to reach the occupants, and from what angles/aspects), as well as various types of trees. I would propose demonstrating this on several examples, illustrating the capabilities and limitations, with existing calibers from existing platforms as comparisons.

            LRRPF52

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            • stanc
              Banned
              • Apr 2011
              • 3430

              #21
              Originally posted by LRRPF52 View Post
              On-target performance would address human targets first. Since every person reacts to projectile injuries in different ways, I would like to see an upgraded standard to ballistic gelatin representing:

              * Tissue compartmentalization
              * Bone structures
              * Body heat
              * Clothing/Equipment
              * Skin and sinew
              * Anatomical orientation
              Clothing and equipment -- such as loaded AK mags in chest pouch -- is already done. The other items you propose not only strike me as an unnecessary complication, but would mean that no two bullets would strike the same bone structure or organ compartments in the same way. There's an infinite number of anatomical orientations that could be used, all of which would give different results. And I don't know how you could test for variations in body heat, since ordnance gelatin is supposed to be kept refrigerated until use.
              Most of us would postulate that long, high-sectional density bullets would be superior to the currently available projectiles in such tests, but that has to be demonstrated.
              To be sure.
              Barrier target performance would include defeating foreign trends in armor, common construction materials for walls and structures, light-skinned military vehicles (will this be able to reach the occupants, and from what angles/aspects), as well as various types of trees. I would propose demonstrating this on several examples, illustrating the capabilities and limitations, with existing calibers from existing platforms as comparisons.
              I doubt that hard body armor can be penetrated by ball ammo, be it M855A1-type or conventional FMJ. Other than that, I concur with the other proposed barrier tests.

              Comment

              • bwaites
                Moderator
                • Mar 2011
                • 4445

                #22
                Originally posted by stanc View Post
                I doubt that hard body armor can be penetrated by ball ammo, be it M855A1-type or conventional FMJ. Other than that, I concur with the other proposed barrier tests.
                Why? It can be penetrated fairly easily with the right velocity and projectile. My 7mm WSM blows through steel plate that AP 308 barely penetrates.



                The little penetration holes are the penetrators from .308 AP, only the penetrators made it through the plate. The big holes are 180 grain Berger VLD's, they blew through, making holes literally twice the diameter of the bullets. Thats an open tip, match bullet, not a penetrating bullet. I seriously doubt that plates that would be cracked by 7.62x39 would tolerate that Berger.

                If you meant that making a 6/6.5mm bullet from a carbine do it, I understand. None of the Grendel loads I tried made it through, Including AP 130 grain loads, though I haven't tried the 110 grain AP loads yet. I think velocity has a big part to play in AP penetration.
                Last edited by bwaites; 05-17-2011, 11:39 PM.

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                • #23
                  There's an infinite number of anatomical orientations that could be used, all of which would give different results. And I don't know how you could test for variations in body heat, since ordnance gelatin is supposed to be kept refrigerated until use.
                  stanc,

                  That is one of the biggest problems I see with ordnance gelatin. While it may represent a standardized medium that projectiles can be compared in, what relevance does it have to wound characteristics in living human beings? A cold gelatin medium might be closer to what brain tissue is like on a corpse in the morgue, but not the breathing chest of a human at 98.6 F. Basic physics tells us that a fluid dynamic environment at higher temperature will provide less resistance to a projectile, just like the wind. We therefore can derive very little from cold ballistic gelatin in a large container if we are trying to extrapolate the results to a dissimilar target.

                  If we are to move closer to establishing predictive wounding characteristics based on shooting something other than the actual intended targets, I would propose simulating as many variables as possible, though what I would recommend is admittedly cost-prohibitive...for individuals and small companies. The necessarily-complex target I described would also facilitate multiple shots in many locations, since there would be compartmentalization, with each organ compartment requiring less tissue-simulating medium per volume. It would also make a great training aid for end-of-course shooting tests in many competitive, evaluative, and instructional settings.

                  Rather than simulating an unreasonable number of anatomical positions, I would suggest a simple fractional model from at least 3 frontal angles in the transverse plane, with varying elevations on the coronal plane, as well as side penetrations on the sagittal plane at varying elevations, to include arm penetrations with and without through-and-through wounds to a simulated humerus. I would also like to see a representation of the pelvis in the ballistic mannequin. A self-healing polymer skin surface could enclose the torso, with replaceable inner components for repeated testing and cost-effectiveness. That is what I would like to see.

                  If standard gelatin were to be used as an interim solution, I would lean towards heating it at least, and arranging a ladder of wet wood rungs in front of it to simulate ribs, with a .50" rubber mat in front of that to simulate the epidermis, dermis, and hypodermis.

                  LRRPF52
                  Last edited by Guest; 05-17-2011, 11:49 PM.

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                  • BluntForceTrauma
                    Administrator
                    • Feb 2011
                    • 3897

                    #24
                    Stan, Liberty Ammunition is here: http://www.libertyammunition.com/Lea...LIBERTY_T.html

                    Unless I'm mistaken, Liberty makes the M855A1 projectile. Any way, here's an M855A1 link from a year ago which makes some points relevant to our discussion: http://bulletin.accurateshooter.com/...n-afghanistan/

                    On Mk318: http://bulletin.accurateshooter.com/...ost-5-56-ammo/

                    John
                    :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                    :: I Drank the Water :: Revelation 21:6 ::

                    Comment

                    • BluntForceTrauma
                      Administrator
                      • Feb 2011
                      • 3897

                      #25
                      Regarding bullet lethality, I'm of the thinking that caliber in non-fragmenting bullets is much less important than shot placement. Pulling a number out of the air, I'd say 90% of lethality is shot placement, and merely requires of a bullet the velocity, construction, and sectional density to penetrate barriers, gear, and body mass to reach vital structures. The remaining 10% wherein we DO give a nod to caliber size, is more relevant to fragmenting bullets whereby a cloud of particles effectively increases the frontal area of the bullet and increases the odds of hitting a vital structure (we've been through all this before, at any rate).

                      Contrary to the fad of and fans for lethality via fragmentation for the past, oh, ten years, the latest U.S. military cartridges, M855A1 and Mk318, are largely non-fragmenting designs.

                      So I look at it this way: An icepick hole made by any bullet in the spectrum of 5.56 through 7.62 is going, in my theory, to be barely discernable to the enemy target. Slight differences come into play when yaw is introduced, and a longer bullet tears a larger swath.

                      So what role DOES bullet caliber play? External ballistics and barrier penetration, for the most part. There one seeks an optimum balance between caliber and bullet length and shape.

                      John
                      :: 6.5 GRENDEL Deer and Targets :: 6mmARC Targets and Varmints and Deer :: 22 ARC Varmints and Targets

                      :: I Drank the Water :: Revelation 21:6 ::

                      Comment

                      • Tony Williams

                        #26
                        Of course shot placement is the main determinant of effectiveness - the most impressive ubermagnum isn't much use if it misses the target - but against that you have to set the testimony of many soldiers who have used both 5.56mm and 7.62mm NATO weapons in combat that the 7.62mm is far more effective in that it puts the target down promptly a much bigger percentage of the time. Despite the fact that the 7.62mm M80 has a slow yaw performance and doesn't fragment.

                        Comment

                        • stanc
                          Banned
                          • Apr 2011
                          • 3430

                          #27
                          Originally posted by JWH View Post
                          Thanks. Although their site really, REALLY bogged down my ol' computer.
                          Unless I'm mistaken, Liberty makes the M855A1 projectile.
                          Their "T3" sure does look like an M855A1.

                          As for making a 6.5mm version, I was calling for that a year ago (and bugging the 68forum guys about a 6.8mm version, too).

                          Attached: 5.56 / 6.5 / 6.8 / 7.62
                          Attached Files

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                          • stanc
                            Banned
                            • Apr 2011
                            • 3430

                            #28
                            Originally posted by JWH View Post
                            Contrary to the fad of and fans for lethality via fragmentation for the past, oh, ten years, the latest U.S. military cartridges, M855A1 and Mk318, are largely non-fragmenting designs.
                            I'm afraid you're in error, John. M855A1 is a fragmenting design. It yaws, then breaks apart into three or more fragments -- steel penetrator, copper slug, and jacket (which may tear into two or more pieces).

                            As for Mk318, it expands similar to a Barnes TSX, and the four "petals" may break off, thereby creating up to six fragments, as the non-bonded lead core typically separates from the solid base.

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                            • #29
                              It's all about retained energy and terminal performance resulting in tissue damage (I must have slept in a holiday inn once)
                              And as Tony said and I have said for many years, shot placement trumps all.

                              Comment


                              • #30
                                Originally posted by bwaites View Post
                                None of the Grendel loads I tried made it through, Including AP 130 grain loads, though I haven't tried the 110 grain AP loads yet. I think velocity has a big part to play in AP penetration.
                                Yep it is all in the math Bill, E=MV2/450400 (muzzle) but if we determine that we retain enough of that a BB would make it through a plate of 4" thick steel if it were moving at 28K fps
                                Last edited by Guest; 05-18-2011, 03:20 AM.

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