Why is steel cased ammo bad for AR's?

Sphawley

New member
Can someone please explain why steel cased ammo is bad for your AR? There are always warning not to cycle it through AR's but what is the reason? :confused:

Thanks in advance!
 
While I can't say that I know for sure, what I think causes problems in the AR platform has to do with a couple of factors.

First a brief overview on how a shell casing works in the chamber. At the instant of firing, the case expands and seals the chamber so the gases produced by the powder are prevented from going back into the guns action. After the pressure spike passes, the case contracts and can then be extracted.

Brass is relatively elastic and shrinks down enough so that it is easily pulled from the chamber and then ejected. Also because it is a dissimilar metal it may have less tendency to gall and stick.

Steel is not as elastic and does not shrink down as much as brass. I was told a number of years ago that the lacquer on the steel cases serves two purposes. One is to keep the ammo from rusting and the other is to aid in extraction as the lacquer melts under the heat in the chamber.

If the chamber is made to tighter tolerances, it could cause extraction problems when the steel case doesn't contract enough to allow the empty shell to easily slide out. The problems might also have something to do with the type of coating that is being used.

I remember a few years ago I shot some Chinese (Norinco) steel cased .223 that was copper plated and it functioned just fine in my match chambered, non chrome lined barrel AR. I haven't tried any of the current steel cased .223 ammo in my AR's, but I have heard that people have mixed results with the different brands that are on the market. It may be that the ability to use steel cased ammo is dependent on the chamber dimensions in a particular rifle.

My AK will digest anything I put through it, so it may also have something to do with the shape of the cartridge. The 7.62X39 does have a more pronounced taper to the case.

If I am wrong about this I am sure someone will correct me.
 
First of all, lacquer on the steel cased Russian ammo will not melt. Secondly, not all Russian ammo is lacquer coated.
The steel cased ammo does expand as does brassed cased ammo. However, the steel cased ammo does not seal the chamber as well as brass does so often you will end up with a more messy chamber as some of the gas bypasses the cartridge.
In general, the Russian ammo is not as accurate as most brass cased ammo but at half the price, it is great plinking ammo. I have a S&W, Bushmaster, and Colt AR15 and all them handle steel cased ammo well with no apparent wear on the rifle.
 
I don't think the steel cased ammunition expands to fit the chamber much at all unless it contracts somewhat right after firing. A few nights back I was sitting in front of the tv where I usually run my spent brass .223 cases through my Wilson case gauge to see which ones need to be fully resized and shortened to specs. and when I placed 18-20 fired steel cased Wolf into the gauge they all measured within tolerances and would need no resizing if I were to reload. So did they not expand hardly at all upon firing or does the steel shrink back somewhat after firing? I don't know but my Wilson case gauge is trying to tell a story.
 
Steel cased ammo is not bad for AR's. The fact that some will choke on it and other wont is what's bad. If your likes it go ahead and shoot all you want. If it chokes on it you should avoid it. The steel used to make the casings and bullet jackets is very mild and wont wear out your barrel or extractor any faster since they are made of hardened steel.

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Wow, someone was up late thinking about this!

Basically, the steel doesn't expand when the cartridge is fired, thereby sealing the chamber. The resultant gas blowby does 2 things: dirties the receiver and drops the pressure in the barrel. The AR was designed to use the gas pressure tapped from the barrel to cycle the bolt carrier assembly. When that pressure is reduced, some ARs won't cycle.

As a component, the steel is cheaper than brass, so there is a reduced cost in production. Certainly across the spectrum of ammo, some steel cased is just cheap across the board in terms of components, and the resultant accuracy bears that out. But Hornady, in an effort to reduce cost for high volume competition shooters, makes a steel cased match line in 5.56 and 7.62.

What I've wondered is if steel cased ammo is like blanks: if you were to run the action wetter than normal, would an AR that choked before cycle steel cased ammo?

RT, excellent find on that thread!
 
Anybody know if the steel cased stuff is annealed at the factory? Different ammo, but I had 7.62x54 copper washed screw up the chamber on a old Russian bolt gun I had. It was the earliest soft point imported and they were just using military cases. The burrs on the rim of the cases were so bad that they chewed up the face of the chamber where the case rim contacted.
 
Another factor to consider is heat. The AR pattern rifle was designed with brass cased ammo in mind, because of the heat generated by firing, impinging gas, and firing again.

Brass cased ammo is meant to act as a heat sink, and bleed some of that heat into the case after firing, and out of the gun upon extraction. Steel cases do not absorb as much heat, thereby contributing to a hotter gun, and potential failures due to excessive heat.

If steel cased ammo shoots fine, extracts fine, and seems to cycle alright, go ahead and use it, but keep the heat issue in mind.
 
Large groups, casings stuck in chambers, possibly accelrated wear, dirty / smells bad. Price is the only advantage. I'll pass.
 
I have two 5.45 uppers and absolutely no choice but to run steel cases---which function perfectly well in either one.

Bad accuracy?
Five Factory 270@100yards, M223 scope, Green Mountain barrel---

396224104.jpg


Steel cases don't seal the chamber?
With a DI system, how in Hell can you be sure of that? My .223 rifles are just as dirty at the end of the day as the 5.45 gets to be. There's no soot down the sides of the cases, either.

You can fault some of the current Russian commercial production in a comparison with the older military 5.45---and I suppose this quality issue could carry through into the .223 commercial steel case stuff.
The indifferent performance of the commercial stuff is not something that can be blamed on steel cases, though.

BTW, I really like the bit about the brass cases being a "heat sink"---I haven't smelled anything like that since last I was down on the farm.
-----krinko
 
If steel did not work, then you would have huge blow by.

It does work. Some guns don't handle it well, some do fine.

I suspect a 5.56 or Wylde chamber would have no issues, a 223 might.

There are also mfg variations on chambers. Its not a dead on spec, its a tolerance (ie so many thousandths plus or minus) If you go to the large side, then less likely for a bind.

I have cross checked my 9mm rounds in a gauge, they do not fit quite right (most). However, the pistol chamber is more than ample.

The gauge is obviously precision spot on and the gun itself they are obviously going to the max allowed to ensure reliable operation regardless of the ammo (or as best it can be).

So its some and some. If it works, fine , use it, if not then don't
 
In my experience, the issues have to do with consistency of the ammo and potential extraction issues.

The steel cased stuff is usually pretty cheap, and it seems to be not only dirtier than more expensive ammo (not always, but I'm speaking in gross generalities), but there also seems to be more variance in the charges... one round will feel stronger than the next. That's going to affect accuracy and potentially cycling.

On top of that, the steel cases can sometimes not "spring back" to size as brass can, and steel has less lubricity than brass, so you can sometimes have a case that won't extract cleanly.

Some ARs will eat steel case with no issues, some won't. I have a BCM upper that will chomp down Silver Bear with nary a hiccup. I have a frankenrifle 20" that just doesn't feed the steel stuff, period.

Personally, I prefer to stick with brass cased ammo in the AR platform; with eastern bloc designs I'll run steel case all day long, but I don't buy it anymore for my ARs.
 
I have a CMMG and they say if I shoot steel casings through it that the warranty is automatically voided...

Anyone know why?
 
Because steel case ammo is crap. It is put together in third world crap holes by slave labor. My guns are expensive and quality. I only shoot ammo that I hand craft with care and precision in mind. Never Unser stand why some one would spend $600+ on a Gunther run the cheapest crappiest dirtiest ammo they can findin them.
 
Speaking with some experience, I have found that my S&W M&P handles steel case ammo well. I have only shoot Brown Bear (very cheap) and Sliver Bear (just cheap) and have NO issues at all. It fires, ejects and is reasonably accurate for my needs.
The posters who describe the steel case as not expanding are correct. If I intend to shoot both brass case ammo and steel case ammo, I will shoot the brass first. Just me. I have heard reports that the brass will stick if you shoot the steel first.
One more thing, in talking to various ammo makers st the recent NRA show, most say there was a change in the tension of the extractor spring and if you can shoot steel yours is fine, if it won't, it might be the spring. Bear in mind, this the ammo people talking NOT the gun makers.
 
Hornady manufactures steel cased ammo....and it is very much assembled right here in the good ol' USA. It is far from "crap ammo".

I didn't realize the USA was a third world country. :rolleyes:

That being said, I've used Hornady steel cased ammo to shoot two 4 day AR-15 training courses. Never had a lick of trouble with it. In fact, I qualified at the top 1% of all of the students who have shot the course over the past 12 years. Not too bad for "crap ammo". :D
 
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