Why isn’t the army using aluminum cases?

[MutinousDoug]

The Vietnam era M-79 shot an aluminum cased round, didn't it? It's been 48 years since I handled one though.

 

[WestKentucky]

The U.S. military issued aluminum cased .45acp ammunition during and after WWII.

I would not believe that without a source. Being involved with metals in a previous job I know how hard (expensive) it was to extract and purify aluminum until technology improved. Yes it was getting cheap, but it wasn’t “cheap enough” yet. It was kinda like titanium is now, expensive but getting cheaper as sources are found and process technology grows. For 1940s I would believe reusable durable items like mess kits and canteens, but not items expected to be discarded regularly and in bulk, especially when the valuable refuse could be collected and used to aid in production of enemy aircraft and/or repair parts.

 

[Vern Humphrey]

The Army issued steel case .45 ACP ammo in WWII, not aluminum. The steel case ammo had problems and was eventually withdrawn from service.

 

[CapnMac]

AL has a number of metallurgical issues--as noted above--when used for rifle ammunition.

Interestingly, tank ammunition uses aluminum cases--but those are operating a level of magnitude above rifle rounds, too. Mush as rifle is a level of magnitude greater than pistol.

USN spent a great deal of time fussing about with AL cased ammo for its fixed ammunition. The only ammunition that looked like that was going to work was the 8" fixed rapid-fire ammo. For the 5" and 3" fixed ammo, the issue is oxidation in maritime storage. Brass veridgris can be scrubbed, or the ammo returned for salvage. The AL has never faired quite so well.

 

[CapnMac]

The 40mm grenade used in the M-79 and a bunch of other platforms is an odd bird.

It uses the High-low pressure concept. Which was first used in Germany in the very later 30s. The case is built up enough to contain the high pressure on ignition. This then, blows out disks/vents in the cartridge between it and the projectile at a reduced pressure, lofting the projo out. The primary gain from this is in not needing a high-pressure proof barrel and chamber. The only real issue is obturation, as you want all the gass in behind the projo. And AL cn do that nicely. And, since the base is cast, the lower casting temps are an advantage, too.

 

[GunnyUSMC]

The 40mm grenade used in the M-79 and a bunch of other platforms is an odd bird.

It uses the High-low pressure concept. Which was first used in Germany in the very later 30s. The case is built up enough to contain the high pressure on ignition. This then, blows out disks/vents in the cartridge between it and the projectile at a reduced pressure, lofting the projo out. The primary gain from this is in not needing a high-pressure proof barrel and chamber. The only real issue is obturation, as you want all the gass in behind the projo. And AL cn do that nicely. And, since the base is cast, the lower casting temps are an advantage, too.

Here is some pics of a 40mm round for the MK19. I fired plenty of it and 40mm from a M203.

 

[MutinousDoug]

I would not believe that without a source. Being involved with metals in a previous job I know how hard (expensive) it was to extract and purify aluminum until technology improved. Yes it was getting cheap, but it wasn’t “cheap enough” yet. It was kinda like titanium is now, expensive but getting cheaper as sources are found and process technology grows. For 1940s I would believe reusable durable items like mess kits and canteens, but not items expected to be discarded regularly and in bulk, especially when the valuable refuse could be collected and used to aid in production of enemy aircraft and/or repair parts.

rounds/minute


40mm M169/M430A1 Aluminum Cartridge Case

Used in gun systems for:
• MK 19 High-Velocity Grenade Launcher
• MH-60L Direct Action Penetrator (DAP) Helicopter

Production Capacity:
• M169 Cartridge Case 1,200,000 cases/month
• M430A1 Grenade Bodies 200,000 units/month
Cartridge Rate of Fire: • 375 rounds/minute (1,500 yard range)


40mm M118/M195 Aluminum Cartridge Case

Used in gun systems for:
• M203 Low-Velocity Grenade Launcher

Production Capacity: 100,000 cases/month
Cartridge Rate of Fire: • 5 – 7 rounds/minute (160 yard range)

That was easy. Should have searched before my 1st post.

 

[Drail]

Gotta love them guys with the bloopers.....

 

[CapnMac]

I know how hard (expensive) it was to extract and purify aluminum until technology improved

Which is why is was a bit of a marvel that they made a circa 1" thick cap of aluminum for the Washington Monument.

 

[patmccoy]

Bloopers were great for immediate indirect fire support, until the mortars or 105s got cranked up.

M79 had about 350 meter range with HP, and also had buckshot, flechete, and smoke rounds (including Willie Pete).

My favorite infantry weapon.

 

[denton]

If you've ever bid on a government contract, you'd know that a $600 toilet seat is a bargain. There are many federally mandated compliance rules, the bids often take months to be awarded, and the process of creating a bid requires a "cast of thousands". It is not unusual for companies to drop $250,000 creating a bid for a contract running a few tens of millions of dollars. If six companies do that, then five of them have to make up that expense on other contracts.

If you're looking for one of the major factors in the high cost of government contracts, look no farther than the rules and processes the government has created for contractors.

 

[Slamfire]

If you're looking for one of the major factors in the high cost of government contracts, look no farther than the rules and processes the government has created for contractors.

The Government has a real problem and I don't think it can be fixed, no matter what they do. Congress is of course the driving factor in Federal Acquisition Regulations, and Congress is always trying to create a scandal free system. For example, at one time it cost the Government about $1 billion in monitoring and travel controls to avoid waste and scandal in $2 billion dollars worth of official travel. At the time, it was said if the $1 billion cost in controls were scrapped, and they simply had $500 million in waste, fraud and abuse, they would come out ahead. Guess what, more costly travel controls!! I have been told that every procurement that goes out the door is a violation of some federal law. The laws apparently, contradict. And then, these FAR rules are amplified and commented on by the services, so you have an Army FAR's added onto the Federal FAR's

And, you have documents such as DoD 5000.1 the Defense Acquisition. Periodically the DoD 5000 series, the AFAR's get so onerous, they get "streamlined". Al Gore did that during the Clinton administration, just gutted all the rules that had accumulated over the decades. It was called Acquisition Streamlining, Unfortunately the premise was that Government officials would think about equipment requirements, have some expertise about what they were buying, and that they cared that the equipment worked. All of these have been proven false. When Gore removed all the learning that had accumulated in the rule based Acquisition system, what was left was a bunch of clueless officials who would not tell bidders to paint fire extinguishers red, green or yellow, because they did not know what was the correct color. Plus they can't get in trouble for doing nothing, even if it costs billions. They are more concerned about a contract protest than about winning or losing a war.

It is hugely inefficient, costly, and no matter what they do, create a Program Manager, streamline, make the contractor the lead system integrator (which took management away from the Government and gave it to industry!), fixed price development contracts, all of these radical changes failed, and cost more money than previous strategies. No one has figured out how to make a rapid, cost efficient, fair, and effective procurement system.

 

[Vern Humphrey]

It is hugely inefficient, costly, and no matter what they do, create a Program Manager, streamline, make the contractor the lead system integrator (which took management away from the Government and gave it to industry!), fixed price development contracts, all of these radical changes failed, and cost more money than previous strategies. No one has figured out how to make a rapid, cost efficient, fair, and effective procurement system.

Well, nobody in government has. In private industry there are plenty of good procurement systems -- look at Wal Mart, for example.

I suspect the government problem is due to two factors -- first of all, government employees are not accountable. You can't fire them, no matter how badly they screw up.

And second, if they were truly competent, they'd be working in industry and making millions.

 

[Reloadron]

The Army issued steel case .45 ACP ammo in WWII, not aluminum. The steel case ammo had problems and was eventually withdrawn from service.

The below are a few WWII 1943 EC Headstamp steel 45 ACP, I have a FA 43 which is brass. The pennies are also 1943 steel pennies. During 1943 copper was a rare commodity so they stamped out the steel pennies. I thought the pennies were a nice compliment to the steel cased 1943 .45 ACP ammunition. Growing up during the 1950s the steel pennies were still pretty common in circulation but today are seldom seen.



Ron

 

[herrwalther]

Being a combat tested (former) Infantry grunt, I would NOT want to risk my combat effectiveness on whether or not aluminum ammo would fire properly when I wanted it to.

There is tons of waste, fraud, and abuse when it comes to military (or even government in general) supplies and logistics. Where I was stationed, about 75% of our supplies were flown in and in some cases air dropped. The only resource that didn't need to be sourced by the military was non potable (non drinkable) water, which we got from a local stream and made as clean as possible for washing clothes/showers etc. Our potable water was in water bottles. 20oz and 1.5L bottles dropped in pallets almost daily. For the price of probably 2 pallets, we could have had an industrial water sanitizer for drinking water. Could never get it to happen. "Too expensive." I burned 26 gallons of paper PER DAY of classified intel reports that had to be destroyed with diesel fuel and at least 2 armed soldiers supervising the destruction. Many of our intel reports were printed out, read ONCE by ONE person. Then shredded immediately. Anyone else who had to read the report needed to reprint it and likewise shred. There are plenty of places you can nickle and dime the military on cost saving, ammo would not be anywhere close to the top.

 

[jmorris]

I would imagine it’s because it can’t pass the tests required for it to be put in service.

Same thing for the plastic cased ammunition.

 

[BSA1]

War, for all of high tech, gee whiz technology and equipment, boils down to one indisputable factor;

A soldier putting a bullet where it matters on the enemy.

Don't think so? How was Bin Laden finally killed?

As a taxpayer I am willing to pay for ammunition that I know will function, fire and put the bullet on target when it is needed most.

 

[Slamfire]

There are plenty of places you can nickle and dime the military on cost saving, ammo would not be anywhere close to the top.

It is a hugely inefficient and expensive organization. Neither Industry nor Government is all that good at measuring indirect costs, but the Government totally ignores the costs of controls. There is a huge amount of time wasted in reviews, layers of management, over sight, but it can't be measured it is considered as free.

One very real reason for not going aluminum for 5.56 case ammunition is that even with brass case materials, function reliability is not great.

The 223 round was not so much “designed” as it was a wildcat. The guys who came up with the round wanted a certain velocity at a certain range. I read the 1971 Guns & Ammo article “The 223 is here to stay” by Robert Hutton. Robert Hutton was technical editor of Guns and Ammo magazine and must have been very wealthy as he owned a big piece of real estate in Topanga Canyon California. It was called Hutton’s Shooting Ranch. What the adoption of the 223 round as a service round shows is how well connected wealthy elites run the country. Hutton’s article documents how he developed the 223 round. If you have any sort of technical background, it is apparent he is an amateur and his cartridge represents what an amateur would do. He took an existing cartridge, necked it up and down, blew the shoulder out, changed shoulder angles, he had a chronograph, got the velocity he wanted at distance. The crowning achievement in the article was punching holes in the wobble pot helmet at 500 yards. That is about all the lethality testing Hutton did, punching holes in a helmet. He used the Powell Computer, a paper slide rule, to estimate pressures. He did not pressure test his cartridge. This cartridge was then adopted as the US service round.

I have no idea of his background, maybe he was the typical liberal arts major you find in the print industry, obviously he was a firearm enthusiast, and being the Technical Editor of a Gun magazine made him well connected. What an ego trip it must have been to have his cartridge adopted as the US service round. Imagine all the bragging you get to do at the dinner parties, “I developed the service round for the Army”. Unfortunately, amateurs don’t have the time, equipment, or understanding to really sweat out the tiny details. These guys did not have the analytical capability nor probably, had the comprehension to thoroughly study cartridge case design. William Davis, the Government Technical Expert at the Icord hearings, said on the History Channel that the technical data provided the Government on the 223 round did come with a pressure curve. These guys developed a cartridge and never thought of documenting what the pressure curve looked like. Pressure curve is absolutely critical to the timing of an automatic weapon. How long energy is available, the maximum pressure and how fast it drops off is fundamental to the design of a automatic gas mechanism.





This is from Chinn's Machine Gun series.



Hutton did not look at case hardness, taper, expansion or contraction. A professional would have looked at the expansion and contraction of the case in the chamber and adjusted case taper, thickness, and established case hardness in the sidewalls and case head. This is highly dependant on case materials, and it will be different from brass, steel, and aluminum. You would have to work with manufacturing to determine realistic hardness parameters throughout the case, but this is important as it affects the Young’s Modulus. As it turns out, the brass case 223 drags on extraction, there is not enough clearance between the case and chamber. Steel case is even worse. I have seen many failures to extract steel case ammunition on the firing line with AR15’s. Can't recall seeing aluminum cases on the line, though they might have been there.

It turns out the 223 is fairly straight tapered. This was a fad, highly promoted by P.O Ackley, and widely copied. I am not a fan of very straight tapered cartridges. The one and only advantage of a very straight taper is maximizing the amount of powder you can get in the case. The wildcat era of the late 1940’s through the 1960’s was all about high velocity, and only high velocity. It was very one dimensional thinking, ignoring other aspects of cartridge design that are very important. One of the things you trade off for a straight case is that the cartridge does not “steer” well during feeding. Anyone can test this, which shape feeds better into the end of the tube, a taper, or a straight cylinder? Alignment to bore is important for feeding with all cartridges, but the really straight ones are going to jam up more often when alignment gets slightly out of whack. Straight cartridges will drag on extraction because the case walls are relaxing off the chamber walls in a straight line, not a diagonal. It turns out portions of the 223 case are still sticking to the chamber walls during extraction and a major reason for extractor lift. Understanding Extractor Lift in the M16 Family of Weapons www.dtic.mil/ndia/2003/smallarms/din.ppt This is very undesirable as jams will get you killed in combat. Lots of good American Boys died in Vietnam with jammed M16’s in their hands. Ideally, the case will be fully relaxed off the chamber walls during unlock and there will not be any resistance between case and chamber during the residual blowback period. If you look at good case design, the Russian 7.62 X 39 and the recent Chinese service cartridge, both have more case taper than the 5.56 Nato and both were designed with steel as a case material. Both have nice thick rims, which is also important for machine gun rounds.

Hutton did not spend time and money examining issues such as pressure curve, contraction or relaxation. Rifles and cartridges that did not go through an appropriate development will have issues with case materials. The AR15 and 223 Remington are an example. You can read all the issues they created here:

http://www.dtic.mil/dtic/index.html

Report of the M16 Review Panel Appendix 4 Appendix 4 Ammunition Development Program.
Report of the M16 Rifle Review Panel Volume 7 Appendix 6 review and analysis of M16 System Reliability.
Report of the M16 Review Panel Appendix 5 Procurement
Report of the M16 Review Panel Appendix 7 Vietnam Surveys
Report of the M16 Panel appendix 10 the small arms program
Report of the M16 Review Panel Summary Report.

The 5.8mm’s corrosive powder is not particularly hot either. It only generates a 41,500 psi (284 MPa) chamber pressure which is marginally higher than that of the old single-base propellant used by the vintage 7.62x39mm and much lower than the 5.56mm M855/SS109’s 55,000 psi (380 MPa). A non-reloadable Berdan primer is used to prime the 5.8mm cartridge’s propellant.

The Russians took into account the material characteristics of steel as a case material, examining the expansion and contraction, along with the production technology, aiding the excellent function design of SKS's and AK47's. As such, these steel rounds are outstanding in feed and extraction. The 5.56 was created without spending any time or effort on alternatives, alternate materials, anything. As such, given the fact the case shape is not optimum for brass, it most certainly is not optimal for steel or aluminum.

And in the real world, what you read, in lots of posts on forums, is shooters having issues with steel cases in their AR15’s, I have not seen data on aluminum, but I doubt it will function all that much better.

Based on my understanding of Federal Procurement, without a champion inside, or the forcing function of a Corporation exercising its power over Senators or high ranked House Representatives, and Secretary of Defense buy in, changing over to aluminum case material is not going to happen. First of all, the bureaucracy does not like change, will resist because it is change. Government bureaucrats do not get a wild hair, start self initiatives, on something that has such a small pay off for their careers. This is not an ACAT 1 program, (Billion dollar level) so the empire building potential, is tiny. Post military employment opportunities for Flag Officers is going to be non existent, so there goes your in house champion. And, the switch over to aluminum case might have problems which will come back to haunt them. Where is the upside in all of this?

 

[dogtown tom]

The U.S. military issued aluminum cased .45acp ammunition during and after WWII.

Idiot.
Do you not know the difference between aluminum and steel?
Yeah, they are both silver in color and if you had a box of that Winchester steel .45acp like me you would know that.

 

[rodregier]

As I understand it, the "siren song" of aluminum or plastic cases for military small arms ammunition
is reduced cost and reduced weight. The later would in theory permit carrying more rounds for the same weight penalty.

 

[rust collector]

The ammunition for the A-10 GAU 8 has an aluminum alloy case due to the weight differential, but I am sure the gun was designed with that in mind and there is a huge difference in priorities. Projectiles are soundly crimped in, heat factors controlled to some degree by multiple chambers and/or airflow, and lots of other adaptations make it work for that purpose. I agree that battlefields are no place for experimentation, however.