Steel Ammo Sticking in AR-15

[41magsnub]

In all the steel ammo threads it invariably comes down to "steel case ammo is the devil" vs. "if your ar-15 jams on it then there is something wrong with the rifle".

Assuming the second option is the correct one, what could be wrong with the rifle that would cause the cases to stick?

In my specific example I have a Stag 20" HBAR AR-15 that works great on Wolf for approx 200 rds, then sticks cases until I give the chamber a good scrubing. This has never happened with brass cased ammo. It is not chromed if that matters for this.

I don't especially care, 200 rds is more than I can afford to spend on plinking and I have a bunch of brass cased M193 as my stash.

 

[KW]

Your particular rifle may have a slightly tight chamber. Also the lack of chrome lining probably results in a little more friction between the case and the chamber walls.

Another problem could be the extractor. There are kits at have an upgraded extractor spring, along with a stiffer insert and rubber o-ring. Together these will greatly improve the extraction of the rifle. I think bravocompanyusa.com has them for a couple bucks.

 

[Bartholomew Roberts]

Is it 200 rounds at one time and towards the end of a session? My guess, based on what I've seen in classes is heat. Steel cases take longer to expand and they take longer to shrink away from the chamber walls. Steel also has a different thermal transfer than brass. As the rifle gets hotter, all of this takes microseconds longer to happen; but sometimes those microseconds can make the difference between function and not functioning.

Cleaning the chamber may allow it to cool enough that the problem goes away temporarily.

As for what is different in the rifle, it could be a number of things or a combination of them - overgassed rifle, chamber cut very tight (or .223 chamber), worn buffer/buffer spring...

 

[RP88]

...It is not chromed if that matters for this...

this is your problem.

I never hear of people running steel case on a non-CL'd AR because this means less smooth extraction - even with brass.

I doubt it has anything to do with a weak extractor or having a tight chamber. Those are two problems that usually show their ugly heads right away if they are present. If you're getting 200 rounds down before problems, then it sounds like your non-CL'd chamber and bore are gunking up and making it even harder to extract, causing stuck cartridges.

 

[41magsnub]

It is 200 rounds in a session, then I clean it, and it is good for another 200 rounds.

It is a 5.56 chamber. The stuck case completely locks up the rifle, the bolt is still on the spent case stuck the chamber.

I end up having to beat the bolt open using the pull back on the charging handle and pound the stock on the ground trick. This frees the bolt from the stuck case so I can look at the primer to make sure it is not a live round in the chamber. Then I pop the case out with a cleaning rod and a rock. After doing this and the gun is cooled down, if I don't clean the chamber the next round does the exact same thing. This tells me it is fouling in the chamber that causes it.

This makes me think it is not the extractor or overgassing, if either of those were an issue wouldn't it pop the bolt off the stuck case itself and probably make things worse by ripping the case head off?

 

[NMGonzo]

If you don't trust them anymore and they are more of a bother than they are worth to you, I'll take them.

For some reason they work well on mine.

 

[Bartholomew Roberts]

It is a 5.56 chamber.

It says that it is a 5.56 chamber or you've measured it and it meets the specifications for a 5.56 chamber? It isn't unheard of for manufacturers to incorrectly mark chambers or cut chambers a little tighter than 5.56 specs in order to give better accuracy.

After doing this and the gun is cooled down, if I don't clean the chamber the next round does the exact same thing. This tells me it is fouling in the chamber that causes it.

That seems like a reasonable conclusion from what you describe.

This makes me think it is not the extractor or overgassing, if either of those were an issue wouldn't it pop the bolt off the stuck case itself and probably make things worse by ripping the case head off?

When the rifle is overgassed, it will try and extract earlier than usual while the case is still obturated and can look similar to what you describe, though it can also rip the rim off too in some cases - a good clue might be to check the rims of the stuck cases, that should give you a rough idea of how much force there is rearward.. I think you are correct about the extractor though since it isn't letting go of the rim.

It might also be a combination of tiny things that wouldn't otherwise be a problem (5.56mm chamber within specs but on tight side, unlined barrel with higher friction, gas port that is a .001" or so too big, plus more chamber fouling due to the steel expanding slower).

 

[41magsnub]

So.. with the possible cause(s), if I were of a mind to do something about this my best bet would be a new barrel that has a proper 5.56 chamber, proper gas port, and chrome lined?

It says 5.56 on the barrel but I do not have the tools to check if it is in-spec or not. It is a factory built Stag Arms except for the trigger which I replaced with a 2-stage so I'd hope it was in spec!

 

[Slamfire]

You have a problem with excessive friction between the case and the chamber.

Put a drop of oil on a hand ful of rounds and roll them around until the oil is evenly distributed on the outside of the cases.

Load them and shoot them.

 

[Bartholomew Roberts]

So.. with the possible cause(s), if I were of a mind to do something about this my best bet would be a new barrel that has a proper 5.56 chamber, proper gas port, and chrome lined?

That is the way I'd go if I were set on shooting steel cased ammo. Having said that, I've seen an Armalite chrome-lined barrel that worked just fine with brass choke on Hornady Training ammo (steel cased). No stuck cases; but continually short-stroked.

As far as I know, nobody has really done a comprehensive look at why steel cases work in some ARs but not others - I certainly haven't - so my suggestion is a SWAG at best.

 

[wally]

It is not chromed if that matters for this.

Yes it matters, you need it.


McNamara pontificated that Stoner was gilding the lily with chrome plating the chambers and bores. This omission (and the switch to cheaper ball powder) was the the major reason for the AR's early problems.

Don't put oil on cases or in the chamber! Don't think lube, think suction cup!

I'd check your extractor. The only AR that has given me trouble with steel cased turned out to have an out of spec extractor, it was fine with brass cased ammo, but substitution of the extractor from one of my problem free ARs proved that was the issue, No issues since I got a proper replacement, and while waiting for the replacement to arrive I filed the bad extractor to match the good and it then worked fine. I replaced it as I'm not sure if the AR extractor has any special surface hardening or not.

Polishing the chamber might help, but making it a mirror-like surface (like your car's brake rotors) will increase friction and likely make things worse.

You may just have to live with shooting brass cased ammo if you don't want an in spec chromed chamber barrel.

 

[taliv]

running one of ned christiansen's chamber reamers might solve your problem. may not make sense to buy a tool that costs almost as much as a barrel if you only own one AR

 

[possum]

my first bushmaster would eat anything, steel included, my current ar dosen't which isn't a big deal since i shoot, and train with pmc 55 gr fmj. the general rule of thumb is if it is a commie gun you shoot commie ammo, if it is an american gun, use brass cased ammo.

if you get an ar that runs steel good, then that is a bonus, but that doesn't keep me from using a rifle just because it won't function well with steel ammo. if it doesn't function with brass cased then there is an issue.

 

[WardenWolf]

Why spend all that money on an AR and not get a chrome-lined bore? Seriously.

 

[FTSESQ]

It may be the coating on the steel cased stuff. When you fire a round, the cartridge case expands and some of the coating flakes off and sticks to the chamber walls. As the chamber heats up the coating stuck to the chamber wall gets sticky. Then you get this sort of downward spiral where the sticky stuff in the chamber collects more coating and gets hotter and gums everything up.

 

[Steve in PA]

The coating does NOT flake off, melt off, etc. The chamber gets dirty from carbon build up because the steel case does not seal as well as brass cased ammo.

If you get a stuck round, stick a chamber brush in there, clean the chamber and continue shooting.

 

[Kwanger]

The coating does NOT flake off, melt off, etc. The chamber gets dirty from carbon build up because the steel case does not seal as well as brass cased ammo.

If you get a stuck round, stick a chamber brush in there, clean the chamber and continue shooting.

+1. I can't believe people are still quoting the now hugely debunked "Lacquer melts in your chamber" internet rumor. And even the carbon build up - I've shot 500+ round sessions of steel case in my AR with zero problems whatsoever.

About the only thing I probably wouldn't try out any time soon is suddenly switch to brass after a heavy session of steel:

http://www.theboxotruth.com/docs/edu18.htm

 

[migkillertwo]

Steel cases normally do not expand as much as Brass, so there's a gap for carbon fouling to build up. It sounds like your chamber is too tight. That's bad, very bad.

 

[migkillertwo]

you should get a better extractor.

 

[41magsnub]

How would a better extractor matter in this circumstance? It takes a cleaning rod and a rock to actually get the case out and the bolt is still attached via the normal extractor.

 

[41magsnub]

Why spend all that money on an AR and not get a chrome-lined bore? Seriously.

Because I screwed up the order and didn't realize it until like a year later. I thought it was chromed and every other model from Stag at that time was chromed except this one.

Any more helpful comments? Seriously.

 

[railroader]

Because I screwed up the order and didn't realize it until like a year later. I thought it was chromed and every other model from Stag at that time was chromed except this one.

I'm like you. I thought all stag uppers were chrome lined too. All I can suggest is to bring a chamber brush with you to the range. Do a quick clean before you get to the point where you get stuck rounds. Mark

 

[W.E.G.]

Let's just call a spade a spade boys.

We all know from the internet that your gun is just no good if it won't run Russian made ammo that uses a different metal for the cartridge case than the metal that the gun was designed for.

Those coatings on the metal, well they just make it better.
Isn't that obvious?

If your .223 semi-auto rifle chokes on wolf, you need to get some sort of "reamer" in there, and make the hole bigger. Don't be a fraidy-cat.

I just don't understand why everybody else can't understand that the way you judge the dependability and quality of an AR-15 is the test of whether it reliably runs the very cheapest ammo on the market. After all, when the apocalypse hits, we know all the obese armchair commandos are going to be running around the drainage culverts at the local mall, scrounging the plentiful ammo - which will surely be lacquer-coated, steel-case, Russian goodness.

 

[NWCP]

The newer Russian ammo has cases that are either coated with a polymer, or lacquer. The rifle heats up, the sealant melts and causes the chamber to become fouled. The only rifle I use Russian ammo in is my CZ VZ58. It was made to digest the stuff and has never had a failure. My ARs get a steady diet of either newer manufactured NATO surplus, or commercial hunting ammunition.

 

[railroader]

The newer Russian ammo has cases that are either coated with a polymer, or lacquer. The rifle heats up, the sealant melts and causes the chamber to become fouled. The only rifle I use Russian ammo in is my CZ VZ58. It was made to digest the stuff and has never had a failure. My ARs get a steady diet of either newer manufactured NATO surplus, or commercial hunting ammunition

What I have read the problem isn't with the coating on steel case ammo. The steel cases don't expand and contract as well as brass case ammo. This causes carbon to build up in the chambers which eventually cause stuck cases. I personally think chrome lined chambers are more forgiving. I have 2 chrome line ar-15s that I run steel case ammo in all the time without problems. Mark