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Old April 1, 2012, 09:46 PM   #1
pistol named Bertha
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help ar 15 bolt stuck

My buddy just got new ar went to fire it and it didn't eject.....took it apart cleaned it real good.....second shot casing didn't eject and bolt stuck....any ideas?
This is what it did to the casing.....
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Old April 1, 2012, 09:56 PM   #2
FrosSsT
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Sounds like your extractor springs should be replaced.
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Old April 1, 2012, 10:00 PM   #3
pistol named Bertha
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Even if Its brand new? Imnot sure what kind of ammo he was using..I hope it wasn't steel..
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Old April 1, 2012, 10:22 PM   #4
mehavey
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That broken rim edge sure doesn't look like brass...

Who made the AR, and...
Who made the ammunition?
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Old April 1, 2012, 10:26 PM   #5
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Quote:
..I hope it wasn't steel..

A gazillion rounds of steel cased ammo is run through a half a gazillion guns every weekend. Most have no issues with it.
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Old April 2, 2012, 12:32 AM   #6
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Possible you are shooting 5.56 through a .223 chamber? The increased pressure can pin the casing to the wall of the chamber. Had it happen to a .308 bolt action I was shooting 7.62x51 through.
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Old April 2, 2012, 02:58 AM   #7
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looks to me like your extractor tore the rim off a steel case.Its a laquered steel case.

I do not know what your extractor is like now,but at that moment,it was working great.

I'm guessing here.Its a new rifle.New chamber.Even a real nice chamber has a little bit of reamer "texture" to it.After a little wear in,the high spots will wear off.For now,betwween the hards steel case and the laquer,it was hanging on to your chamber a little too well,
Now,let me guess,this is a carbine with a short gas system?

Its trying to unlock while the pressure is still too high.Who knows the burn rate on the powder,it may be slow.

Before you get too excited,try some different ammo.

It may help to get a heavier buffer,like a Colt H-2.

A gas operated semi-auto is dependent on the pressure curve of the ammo.That you have found some offshore steel ammo that your rifle does not like is not necessarily a problem.

I bought some Greek Olympic ammo that just was crap in my rifle.
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Old April 2, 2012, 03:51 AM   #8
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I second HiBC's post above. Your extractor is not the problem--it held the rim and ripped it right out.

Step #1: CLEAN the chamber well. Use the GI-spec chamber brush and be generous with the solvent. Really work it well within the chamber, and dry the barrel extension (where the lugs lock into) and the chamber well with multiple patches. Make sure that you clean the barrel as well.

Step #2: Do a chamber check. On a range, or pointing the rifle in a safe direction, chamber a round from the magazine. Remove the magazine, and pull the charging handle to the rear; the round should eject smartly. Inspect the bullet for any sign that it is being driven into the lands. If the round ejects cleanly, go to step #3.

Step #3: On the range, chamber and fire one round, loaded from the magazine. Make sure that the problem does not occur again.

Post your results, please. Good luck!
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Old April 2, 2012, 06:15 AM   #9
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Coulda been a bad lot of ammo. Had some do that on a qual range. Looked a lot like that. Was shooting from the foxhole supported and the last round did had the edge of the case ripped off, case stuck in the chamber.

Just to show how bad army qual ranges are (at least at ft lewis) I shot 20 rounds, STILL managed to get a score of 26/40 AND qual on the nbc fire....but only shot 20 rounds.
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Old April 2, 2012, 06:50 AM   #10
oneshot onekill
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Looks like Milsurp ammo and no signs of overpressure (the primer is not flattened). What brand of rifle/upper is it? There are some pretty crappy-made AR's out there. I wouldn't be surprised if the chamber wasn't FUBAR right from the maker.
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Old April 2, 2012, 07:11 AM   #11
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Quote:
Possible you are shooting 5.56 through a .223 chamber? The increased pressure can pin the casing to the wall of the chamber. Had it happen to a .308 bolt action I was shooting 7.62x51 through.


The pressure difference between .223-5.56 and .308-7.62 is insignificant. Why perpetuate this incorrect internet folk lore.
.223-5.56 is barrel leade.
.308-7.62 is head space and case thickness.



To the OP, I would check the chamber size. It could very well be undersize. That case appears to be mil-surp (sealer around primer). If the extractor is ripping the rim off the case you have either a tight chamber or a sever timing issue (over gassed) or both.
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Old April 2, 2012, 08:06 AM   #12
pistol named Bertha
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Thanks for the input guys......ill show this to my buddy and ill let you know how it turns out. Supposedly the ammo is Remington bulk buy from cheaper thN dirt.
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Old April 2, 2012, 08:07 AM   #13
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I agree on the chamber size. That's the first thing I thought when I saw the picture. Once the round is fired the case will temporarily expand. If that happens in a 223 chamber with a 556 round it could result in exactly what that photo is showing; the difference between the two rounds is very small but it's enough to get a round stuck in the chamber after expanding for sure.
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Old April 2, 2012, 10:15 AM   #14
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Is the chamber chromed? I've shot steel case ammo through an unchromed chamber before and was getting that same result. It was a carbine length gas system on a 16" barrel, so it was a bit overgassed to start with. It wasn't a chamber issue, it was just the rifle had extremely positive ejection, and the steel stuck inside the chamber (chromed chambers have a bit extra lubricity compared to regular chrome-moly steel, and the steel cases aren't as smooth as brass).

IMO, it may just be that this particular rifle should not have steel case ammo fired through it. I have several ARs... some will shoot that steel cased stuff all day, others won't. I just quit buying the steel cased stuff- when it works, it's fine, but it just isn't as consistent (and it seems to generally be loaded a bit lighter anyway).
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Old April 2, 2012, 11:27 AM   #15
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Another thing it might be. It looks like his extractor is frozen in place. My brother had a DPMS that had the same problem. They didn't finish cutting the opening in the bolt and the extractor could not move. It would lock the gun up with the 1st round fired. (Good thing they test fired it before it left the factory...)

Take the extrator off the bolt. Make sure there is nothing causing it to bind. With it assembled it should be free to move. If you can't, it isn't working right and whoever produced the rifle needs to replace the bolt.
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Old April 2, 2012, 05:43 PM   #16
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Tell us more about the rifle. Barrel length, length of the gas system, what buttstock (receiver extension), buffer weight, etc.

With short -M4 length - the pressure at the gas port is approximately double what it is on a 20" rifle. Also, since the bullet passes the gas port so much sooner, the cartridge case may still be obturated (still expanded against and gripping the chamber wall) when extraction happens, or maybe tries to happen, and exactly this is the result.

Where did he get the rifle? Who built it?
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Old April 2, 2012, 10:38 PM   #17
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Quote:
Had it happen to a .308 bolt action I was shooting 7.62x51 through.
that's interesting since it's 308 which is not compatible with 7.62x51 not the other way around. common misconception that even I was unaware of for a long time.

OP
I had this happen in the first batch of bulk ammo I bought for my AR. it was supposedly "once fired" reloads that were loaded to within M193 specs. however they were loaded so hot and some of the brass was so worn out that the casings swelled and nobody could move the bolt to extract them. we had to let the gun cool for several minutes and then we proceeded to break a number of cleaning rods attempting to ram the casing out. after the second occurrence within 50 rounds I took the ammo back and never went back to that store ever again.
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Old April 3, 2012, 12:54 AM   #18
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Have had a similar issue. What I thought initially to be an extractor issue ended up being a bad barrel not installed correctly. Due to this, the case would jam up in the chamber and the extractor would literally peel the rim of the case back. Getting the cases out was a chore, as I had to ram them out from the muzzle.
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Old April 4, 2012, 04:04 PM   #19
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I would suspect an out of tolerance condition in case/chamber dimensions, or a really hot round.

Breech friction is in fact bad for semi automatic mechanisms. If the bolt cannot pull the case out, the gun will jam. If the case is an mechanical interference fit in the chamber before firing, after firing it will be wedged in the chamber even more. If the case is hard stuck in the chamber, a semiautomatic mechanism will then rip the rim off, or break its extractor.

Another issue, one that got a lot of GI's killed in Vietnam, is high port pressures. This was due to using powders with inappropriate pressure curves in the weapon.

If the pressure curve at unlock is too high, the case is stuck to the chamber walls, and the semiautomatic mechanism will rip the rim off or break its extractor.

So, if the round was hot, or was using powder that gave an inappropriate pressure curve, then that could be the problem.

The AR15 was not designed with steel cases in mind and the extra friction between steel and the chamber could be the issue, but I am more inclinced to think you had a hot round.
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