The Truth About Steel Cased Ammunition

As a small arms instructor and range safety officer, I frequently see AR platform rifles lock up using steel cased ammo. Many think it is due to lacquer or ploymer on the case to prevent rust gumming up a hot chamber. But is that really the reason? And will steel cased ammo really damage your AR?

800px-7.62x39_-_FMJ_-_2There are two “accepted” points of view in regards to shooting steel case ammo in AR platforms rifles. The first is that it will damage the chamber and extractor, and the second is that stuck cases in chambers are the result of lacquer coating on the cases getting hot, and sticking to the chamber walls. Since I don’t run the AR platform, preferring the AK, I never really paid a lot of attention to these issues until recently. However, I had always wondered about these issues since steel cased ammo has been used for a long time around the world, so I decided to do some research as I plan on buying an AR platform rifle for business purposes. The Germans began using steel cased ammo at the beginning of WW2 due to difficulty in securing enough copper to make brass. It was also lacquer coated to prevent rust on the cases. This ammunition functioned perfectly in their weapons from climate extremes of North Africa to the frozen Russian front. Nor did they seem to have a parts breakage or wear problem using it.So lets look at the two issues separately.

Abnormal Wear and Breakage

To me, this is pretty simple. Wear is a function of a harder surface contacting a softer surface. The steel used in steel cased ammo is a pretty soft steel while the steel used in rifle barrels and parts is much harder. I honestly do not believe that running steel cased ammo through your AR is going to cause any extensive additional wear or damage.

Lacquer or Polymer Coating Gums up a Hot Chamber Causing Cases to Stick

The problem primarily seems to be using Wolf manufactured 5.56mm cartridges in AR series rifles. I have shot a tremendous amount of steel cased, lacquer coated  7.62×39 and 5.45×39 ammo through Aks and CZ-58s to where the barrels were hot enough to light a cigarette on, and after inspecting the spent cases, the only damage I saw to the lacquer was the scratches caused by ejection. The lacquer showed no signs of melting and coming off the case. In addition, Wolf no longer coats steel cases with lacquer, having switched to a polymer coating, yet Wolf manufactured (and others) steel cases still will lock up in AR rifles. So what gives? There are a number of concurrent issues involved.

To understand whats going on here, you have to understand the different characteristics of steel and brass cartridge cases. When a cartridge is fired and the pressure builds inside the case, the case wall expands against the chamber forming a seal preventing the gas from flowing back inside the action. Brass is much “springier” than steel and expands better forming a better seal. Steel cases often do not expand as well, and allow a certain amount of gas back into the chamber causing an increase of carbon build up in the chamber. Then, when a cartridge does expand properly, it can lock in the chamber due to excess carbon.This is not a problem with weapons designed around steel case ammo such as the AK series weapons with looser chamber tolerances, but with most AR’s the tolerances are tighter and this increased carbon build up is a factor.

I volunteer often as a range safety officer at the range I teach at, and every time I have seen a steel case lock up in an AR chamber, there was one common denominator: The rifle was bone dry with no lubricant, and extremely dirty. Many new AR owners are not aware of the lubrication required on this rifle, especially the bolt carrier group, and shooting them bone dry can be a serious factor in malfunctions, including stuck cases. You should use a good quality synthetic lubricant.

If you want to read a really good article about a serious test between steel and brass case ammo, check out this article on Lucky Gunner.

Bottom line?

  1. Steel case ammunition will not wear out your AR faster than brass case ammunition.
  2. It is not lacquer or polymer coating on steel cases that is causing stuck cases. It is the increased carbon build up with steel case ammo.

So if you are running an AR series rifle and want to take advantage of the cheaper steel case ammo, what do you do?

  1. Keep your rifle clean. You should give it a good cleaning every 500 rounds or so.
  2. Keep your rifle well lubricated.

You may find that your particular AR will simply not efficiently digest steel case ammo in which case you will need to feed it brass cased rounds or another option such as zinc coated steel.

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51 thoughts on “The Truth About Steel Cased Ammunition

  1. I Agee with the conclusions in the article particularly regarding the softer steel used in the cases and the need to lube AR’s generously- the U.S. actually used steel case .45acp during WWII without issue.

    My concern with the Russian steel case ammo isn’t the case, it’s the bullets. The bi-metal jackets on the russian bullets will accelerate wear in the bore vs copper jacketed bullets. I’ve seen the same effect in both handguns and M-4s using lead free / frangible ammunition. I would save them for melonite or chrome lined bores only since they should be a bit harder and resistant to wear than, say, a stainless barrel.

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    • In the mid 60’s I had the chance to shoot surplus U.S steel cased .45 ammo quit a bit, and it functioned flawlessly. I am still researching the bi metal bullet issue. I suspect that there is a slight additional wear issue, but to what degree?

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  2. Just want to comment on your professionalism and knowledge. Coming from someone new to guns reading your articles it’s easy for
    Me to understand what you are saying and you break it down well. Thanks again!

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  3. Was issued a M16A1 during Basic in ’84. It had “Mattel” stamp on it, same logo as on my G.I. Joe’s backsides. Between that and the RO throwing down an AK in the red mud and rock of Alabama, jumping on it, shaking it out and putting a full mag down range and on target, I’ve been an AK man ever since.

    I now have a bullpupped RPK and Saiga12. I shoot with a buddy(another Vet) who has an AR. I think he’s a bit frustrated that i can shoot as well or better with my BRPK than his AR. Fortunately for ARers, brass 556 ammo can run within about $2 of steel case lately.
    Nice article btw.

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    • I havn’t had the chance to play with a bull pupped RPK. Look forward to it some day. I had a friend who carried an AK pistol version in his car. It was interesting.

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  4. I am not an AR owner but I have an ACR. I’m curious to know if my gas piston system would have a problem with steel cases since I get almost no carbon buildup in the chamber. Think I might test that one. I never have malfunctions as it is. Food for thought.

    Being an army paratrooper I’ve shot many rounds through the AR but I always loved the AK. It was my favorite until my ACR. Love the gas piston. Works like a charm everytime.

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    • I suspect you gas system probably has a lot to do with your weapon’s reliability. A lot of AR owners are not aware of the background of it’s gas system and all of the problems with it in regards to ammo and propellent type going all the way back to Vietnam.

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  5. Pingback: A good read! (The Truth About Steel Cased Ammunition | Azweaponcraftprepper) | Individuals Talking Back

  6. Funny isn’t it, the backwards knuckle dragging Russians invent a gun for all seasons in 1947, not fussy what it eats, or where it is used.
    Yet it is used by children to OAPS effectively every day, everywhere.
    Nice one Mikhail.

    On the other hand the technically superior US make one which is over designed, fussy about what it feeds on, and needs good training to allow it’s users to maintain and use it effectively. Add the insult that it comes in a garden gun caliber is it no wonder why the West has gone back to 7.62 or even 50 cal having taken on (and lost to) the AK once again..

    But this is not an exclusive US trait though. Take the UK’s abortion we call the SA80 in all it’s variants. The cheapest design that needed the most reworking to get it working EVER in UK military history. Even worse, (like the good little sheeple the UK MOD procurement are) it also comes in the garden gun caliber 5.56 x 45.

    This from a L1A1 SLR and AK lover!
    Two real combat proven weapons in a real caliber.
    Long live the 7.62 x 39 in all it’s flavors and the 7.62 x 51 NATO.

    As for the love affair with the 50 cal some have?
    Too much gun in weight and power IMO.
    You want to shoot that far the whole time?
    Phone for a drone ’cause with it’s payload close is good enough.

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    • In the Army, I did an exchange trip to Australia back when they were still using the L1A1 (FAL). I got to shoot their qualification course with it, and fell in love. A tad heavy, just like our M-14, but extremely accurate. I can understand the need for a smaller sized round than 7.62 NATO, but from my experience from Vietnam through Afghanistan, the 5.56mm round is marginal at best. Even the Russian 5.45×39 is better as it has a heavier bullet that is designed to tumble. Ongoing combat experience with both the AR series and the 5.56 is unsatisfactory. Many intermediate rounds exist that would be much better including the 7.62×39 or even the experimental Brit. .280.

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      • The Garand was lovely yet replaced by a lesser weapon. The L1A1 was lovely (and yes I’m still hopelessly in love with it) yet it was also replaced by another lesser weapon.

        Ammo? 0.3, 0.308, 7.62, all lovely rounds.
        They all worked a treat in the older weapons in all flavors and variations YET progress has made things worse. It always does.

        Heck the Russians have always got it right and keep to the same tried and tested design. One up for common sense I’m thinking.

        My dad was right all along though and was spot on to question my trade of fixing things.

        “If it ain’t broke, don’t fix it” he’d say.
        Never were truer works uttered.

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        • I have a mint M-1 that I was able to get through a government sales program when I was on the Army Shooting Team many years ago. This was the first high power type of rifle I learned to shoot on, my high school ROTC having many and our local rifle club had sanctioned matches using them. My stepfather had a National Match M-1 he let me use. “Classic” is the only word to describe them.

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  7. Never fired an AR when they came in. I trained with a Garand in ’64. Would much rather be in a fire fight with a .30 caliber rifle/carbine than .22.

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    • I had the M-1 in High School ROTC, the M-14 in basic training, and carried an M-16 A1 in Nam. Have used about every variety of AR and AK from Vietnam through Afghanistan. In my opinion, the Russian 5.45×39 is a much better round than the 5.56mm. Other than that, I agree that .30 cal is a winner.

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    • I own two Garand’s. One in 308 and one in 30 06. I went to Vietnam with the M16. I was a dog handler and got the cut down version we called the CAR15. It only took me all four years of my enlistment to qualify ‘expert’ with the M16.. The last 18 months I was on active duty I had joined the “Rifle/Pistol” team on my air base. One day I brought my Garand to the range. I had over 400 rounds of surplus
      30 06 ammo that was all dated 1945 or 1946. The Capt was a bit upset that my score was quite a bit better with the heavier rifle and larger caliber. I let him fire the Garand. The first mistake he made was he didn’t hold it tight enough. And, yes, the second mistake he made was getting a case of “Garand Thumb”. Yes, I love my .30 calibers.

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      • The M-1 is a classic, Old School rife. It demands that you learn it and all of it’s ways. If you do, it will perform splendidly for you. If you don’t, it will bite you. It was made in the days when marksmanship mattered.

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  8. Interesting! I am not an AR owner, also preferring the AK. However, this was not one of the reasons that I made that decision.
    Sure makes me look smarter, though!!

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    • Hi Bill,
      Glad you enjoyed the article. I have used the AR system from Vietnam through Afghanistan as well as the AK, and still prefer the AK. It’s all about eating whatever I have to feed it, and going bang every time I pull the trigger.
      I sincerely appreciate your posting your comment and please continue to do so. Thanks!

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