Crane Using Lightweight .50 Cal Ammo

Special guest “18D” sent us this post on polymer cased 50cal ammo being tested at Crane. Stay tuned for more from 18D in the coming months…

Naval Surface Warfare Center- Crane, has been quietly testing polymer cased ammo for the .50 BMG. The best part about this new ammo? It works in conventional weapons systems. This means that our troops can benefit from the lightweight of polymer cases right now, instead of 10 years from now.

It is almost identical to the standard M33 ball round, however with a significant weight reduction. It features a clear polymer case, with a standard brass head fused at the bottom. The polymer cased ammo comes from an aerospace company called Mac LLC., who started a special division specifically to deal with “lightweight polymer solutions for the lightening of components”.

The new ammunition is being tested primarily in heavy machine guns, and has been performing very well.

The most exciting thing about this new technology is that it has already been type classified as the MK 323 MOD 0. This tells me that the new ammo has already proven itself and is here to stay. However it is unclear when or if the MK323 will be fielded in large quantities to the warfighter overseas or used for training.

Either way, the MK 323 MOD 0 will give the troops on the ground a significant weight reduction as opposed to standard brass casings. This will allow the warfighter to carry up to 40% more ammunition.

— 18D

32 Comments on "Crane Using Lightweight .50 Cal Ammo"

  1. Should I do a full-length resize, or just neck-only with these when reloading?


  2. I worked with a company in upstate NY who was trying to develop something similar. Can't remember there name, NATEC I think. Know they were having issues bonding brass casing to the polymer shell. durring extraction the brass would rip off and the spent casing would jam up the weapon.

  3. man oh man i sure hope they test this stuff FOR REAL, and not just take the companies word for it after a few hours of range testing.

  4. Hasn't polymer cased ammo tested previously and shown to commonly have problems with case ruptures? Is there anyone in the know that could explain what the difference is now?

  5. They did this with 5.56mm 6 years ago and it didn't preform well some necks would brake off in a chamber of a M-4 or M-16. The enlargement to .50 BMG is too dangerous that's alot or heat and pressure for plastic to take on. Aluminum is stronger but it too cant hold up well for even pistol ammo.

  6. Also helps out in a time when mineral assets (brass in this case) are through the roof!

  7. They should do a plastic case for the 5.56's. Heck with telescoped cases, this is the way to go. If it works on a 12 gauge then it works for rifle cartridges. Should have put this in the m885a1 too.
    If we would do this to the .308 then it would solve the weight issue and we could get them back.

  8. Seems hard to believe that 40% of the weight of a loaded 50 BMG round is the forward 75% of the length of the brass case.

    The powder charge weight is the same.
    The Bullet is the same.
    The rear 25% of the case (which is the most dense) is the same
    Someone chop up a piece of 50 brass and weigh it.

    Even if it were only 25-30%, it would still be nice though, IF the reliability is a wash.

  9. OK, I just did some math based on actual weights of powder, bullet and brass and a guess at the % of weight savings they might get out of that amount of brass eliminated. I came up with an overall/total weight reduction of 32%, so 40% seems within the realm of reasonableness…

  10. Almost a third of the weight reduction of .50 BMG sounds pretty good and 40% sounds even better. Doing this with .50BMG is probably because working with as large a round gives you room to make thicker case walls, whereas a polymer case 5.56×45 probably doesn't give the polymer enough leeway to be reliable. I really hope this tech can scale down at least to a .308. The question then is going to be, load up on a ton of 5.56, or get the weight savings and leave it, or break even with .308.

    I also do like that the case is blue and glittery.

  11. They better update the TM's. We had a problem with headspace, the cases on our .50 brass were rupturing. I'm guessing this is the chocolate to the M2E2/M2A1 peanut butter….

  12. This is a step in the right direction. Start with the larger scale, test it, tweak it, make it work, then start scaling it down for man portable smallarms. Its kind of funny, the M2 and .50 BMG are actually a scaled up M1919 and .30-06 respectively [yes I know its not a 100% comparison, but you get the point]. Now they are starting with the big boy, and looking to scale back down.

  13. Alex (not a gun nut) | September 14, 2011 at 7:58 am | Reply

    Talked to someone about 2 years ago who was friends with a tester of this amo, turns out that when firing it through an unmodified 50cal machine gun that it would shoot faster, not sure how much faster but it was very obvious. Don't remember the name of the company though, and I don't know if it's the same as the one as made the amo mentioned above.

  14. I think that the CG might be interested in this amo for the helos.

  15. Yeah but most local Sheriffs Dpts left it it cracks too easily. as for plastic rifle ammo they tried this before with 5.56mm and the necks broke off during firing too easily. Not good

  16. Pretty similar concerns for conventional ammo, whether or not the solid propellant will attain a consistent density to ensure a continuous burn rate, as I would really hate for there to be some kind of air bubble that causes the round to misfire and then have to clear an FTE with a partially live round, or have a round lodge in the bore. That's a really nice thing that you don't have to worry about with conventional propellant, as the powder just falls into form. From the looks of the polymer cartridge and the band wrapping around neck I'm guessing they have some of the sealing issues worked out, but that's another concern in caseless ammo. The physics of conventional ammo is pretty neat, as while the bullet is seated in the cartridge, the force from the expanding gas is placed on the back of the bulled and the floor of the case, with some going towards the expansion of the case which can actually help maintain a slightly more complete seal on the bullet as it exits the case, lessening the amount of gas that escapes around the bullet. Also, the energy transfer from the weapon to the propellant is much higher as the case would usually dissipate some of this and slow the transfer, that and that there's no case to insulate the chamber walls and there's more wear on the chamber walls due to the direct exposure to the combustion. Just a few thoughts.

  17. Also, do you guys have a suggestion box or an email? I have something interesting I'd like to get you guys' opinions on. I'll give you a teaser: Semi-auto .338LM's.

  18. Do you mean faster as in rate of fire or faster as in the FPS of the projectile?

  19. The SP-4 ammo is a cool design. It was a concept that actually worked and from what I understand is still being used. There is essentially a piston between the powder and the bullet. When the charge is ignited, the piston propells the bullet. The cool part is that the piston continues forward after the bullet is released and seals the neck from allowing gases to escape. Since its the gas that makes firearms so loud, the sound is contained within the case.

    I think there could be a niche use for this kind of ammo. However it probably isn't realistic for high pressure rifle cartridges. The complexity of loaded ammunition is of concern as well. Anytime we add more parts to a simple design, we add weight and run the risk of reliability issues. You are more than likely going to run into cycling problems with the gun as well. I'm not sure how accuracy would be with this system either. Accuracy is dependent on many factors, but its the gas pressure exerted on the base of the bullet that makes a difference right before the bullet leaves the gun. This system eliminates that, so its hard to tell if that would negatively effect accuracy or help it.

    Either way, I like the idea for short range use in handgun weapons systems.

  20. Something I left out was the law of conservation of energy. Since energy can neither be created nor destroyed, I would think there would be some heat concerns as well. Not only that, but how will the bullets be seated In the cartridge. There has to be some concern that if the bullet Is too tight, the round might not be propelled. If the round Is too loose, cycling could cause bullet setback and drive pressure up. High pressure in this design, like stated before could have serious consequences.

  21. Blazer is crap. The rim shape is all wrong, so some guns will fail to eject the casing almost every time. They made it this way so it wouldn't fit in a shell holder, because they cared more about making sure you didn't try to reload the casing than whether or not it will function with every weapon.

  22. bbb- I'm sorry that CCI/Blaser ammunition doesn't work for you. I have had no problems with it at all. My pistols and revolvers are of old and relatively new manufacture; I have experienced no malfunction due to the rim thickness. I use safariland speedloaders exclusively and had no problems. Others, I have observed who use other brands of speedloaders have had no problems with the aluminum case either.

    As in all mass manufacturing you build to fit in general as many variations as you can, but in no way can you mass manufacture a cartridge to fit all chambered for a caliber, just sometimes it just doesn't work for one reason or another. You see SAAMI specifications have tolerances (variations in dimensions) and for you CCI/Blaser does not work. For example, let's say you have a custom match rifle chambered for .308 Winchester and several boxes of match ammo from various manufacturers, you discover two brands of ammunition that will not chamber and three brands don't group well. Is this the fault of that ammunition maker or is it the fault of the custom smith who cut your chamber or is it just the tolerances just came out that way? In truth it could be a combination of all three and you won't know until you do a detailed analysis.

    That is just the way it is; each gun is an individual and no two are completely identical.

  23. Tony Williams | October 7, 2011 at 8:36 pm | Reply

    Just a comment on the weight reduction: "up to 40% more ammo" is not the same as a 40% weight reduction.

    The math works like this: one .50 cal round weighs c.115 grams. 100 therefore equals 11,500 grams. If you are carrying 40% more ammo for the same weight, that means that 140 rounds also equal 11,500 grams – so one round equals 82 grams. 82 g compared with 115 g is a reduction of 29%.

    In fact in an MG the reduction would be less than this because the weight of the belt links needs to be added in. Unless they are making these lighter too, they will continue to weigh 17.5 grams each. So each round of belted ammo will weigh 99.5 g compared with 132.5 g at present – a weight reduction of 25%. Still very much worth having, provided there are no disadvantages.

  24. Wow …a troop can carry 40% more 50 BMG?????? A can of belted BMG is a can of belted BMG. Will I now carry 1.4 cans of belted BMG???????

  25. Extraction of ammunition also depends on friction of the case against the cylinder wall, so in theory it could slow the MG

  26. I see this being more useful in the m107a1 than "Ma Duce" the main advantage of brass casings is the fact that they extract head from the weapon when ejected.

  27. J. – very cool, I have always wondered about that Soviet piston pistol!

  28. Look at the color of the bullet – I'm betting it is copper, not lead, and part of the weight 'savings.'

  29. I have tested this ammo, and the "match" variant with a opaque green case in a Mk15 (my civilian version) bolt action rifle. My partner and I have been helping to test this ammo for the past 3 years. FYI, the bullet is a standard M2 ball bullet, no difference there. The black band you see is the "tar" waterproofing sealant. We have tested both variants in my bolt gun and his M82 Barrett with mixed results. I had problems after several rounds where the very lip of the case separated and stayed in the chamber, and after a few rounds, I could no longer chamber a round. My partner has been able to shoot in out of his M82 without problems. We have been providing feedback and suggestions to the manufacturer for 3 years now, and I do not believe they have all the bugs worked out yet.

  30. Brian B. Mulholland | April 19, 2014 at 7:58 pm | Reply

    Extraction of a metal case from the chamber serves as an exhaust, removing a good deal of unwanted heat. The caseless 255 mm round originally intended for the F-15 was ultimately dropped, in part because the lack of this heat exhaust proved destabilizing. I wonder how well the polymer cases do, in that regard.

  31. Brian B. Mulholland | December 10, 2014 at 4:34 pm | Reply

    Brass cases serve as a radiator, and their ejection removes a good deal of waste heat from the chamber. I wonder how well the polymer cases function, in that regard.

  32. Actually brass cases act as heatsinks compared to most polymers. The brass absorbs a small portion of the heat of combustion. A portion of that heat is transferred to the chamber before extraction, and the rest of course travels with the hot case. The polymer case will typically absorb less combustion heat so the propellant required for a given MV is a little less. But the chamber is heated *less* by the polymer case than by the brass case. That is good, but the polymer case similarly absorbs *less* heat from an already-hot chamber. The result is that polymer cases are more efficient in propulsive operation, but allow more rapid heating of the chamber. That increases cookoff and premature heat damage to the chambered polymer rounds, and rim separation in many rapid-fire events as mentioned earlier.

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