During our last training session one of our people had extraction problems when shooting American Eagle (Federal/Lake City) AE223 ammunition (55 grain 223 Remington). He had frequent stoppages because the extractor tore the cartridge rim off and left the case in the chamber:



Although the case head looks like typical Lake City 5.56mm NATO ammunition, the box is clearly marked “American Eagle 223 REM. 55 grain FMJ.” The case shoulders also have the annealing discoloration polished off which is usual for other American commercial loads. After he experienced several ripped off case rims and failures to extract, I gave him similar American Eagle ammunition, but which was marked “5.56×45mm 55 grain FMJ.”

After the switch to the 5.56 ammunition, the officer had no more extraction problems. I believe he assembled the rifle himself, and he said he was using an H2 buffer and flat action spring of some sort. I didn’t ask about system length, but it was either carbine or mid-length. The officer is a very skilled and experienced shooter, and is very familiar with AR type rifle armorer methods.

It seems to me that the ripped case rims were due to some sort of pressure curve/timing issue, possibly because the bolt started moving to the rear before the chamber pressure had dropped enough to release the cartridge from the chamber. The cartridge cases themselves exhibited no high pressure signs, and the pictured case drops in and out of a chamber gage easily. The problem cases did, however, require a tap from a cleaning rod to remove from the chamber itself.

The same AE223 ammunition has been issued to several other officers with various makes rifles for years and I have fired thousands of rounds of it myself; none of us have had any problems, including the day of the training.

So, what say the forum authorities? Can anyone think of an easy mod to the one officer’s rifle that would eliminate the problem with using the 223 ammunition and not be limited to 5.56?

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Update. The individual tried a different lot of the otherwise exact same ammunition, and had no further problems. I checked some of the things mentioned here, and there was nothing obvious to wonder about except for the flat action spring. As I mentioned, no one else had any problems.
Again, thanks for the ideas.

This message has been edited. Last edited by: sigfreund,

quote:

flat action spring

This sounds suspicious to me.

Unless his gas port is seriously over-sized, H2 should be the correct buffer.

I would swap out the spring and see if he still had the same issue.

Also pick up some other brands of .223 to try, could just be the AE stuff is over charged. This is an interesting scenario though, typically if something like this was to happen it should be the 5.56 causing issues...

quote:

Originally posted by LDD:

quote:

flat action spring

This sounds suspicious to me.
...
I would swap out the spring and see if he still had the same issue.

Thank you; that would be something quick and easy to try.

quote:

Originally posted by CandyMan.45:
This is an interesting scenario though, typically if something like this was to happen it should be the 5.56 causing issues...

That was my first thought as well, but I checked everything carefully to ensure I didn’t have something mixed up and that’s exactly how it happened. As I mentioned, the AE223 has never shown any high pressure signs; the above photo is typical.

We will probably try some other 223, but I don’t want to give up using AE223 because we’ve had such good luck with it for a long time. It’s usually the least expensive 223/5.56 I can find that’s still of the quality I want. American Eagle M193 is just as good, but sometimes more costly and not as easy to find, so we have large stocks of the other. I could work around this problem if necessary, but would prefer to cure it.

Does your extractor Spring have the "Donut" & plug kit on it?


I believe it's actually called a buna plug & ring kit but we always called it a donut.!?

Looking at the butt end of that brass, is that a huge ejector stamping on the right side about 9 o'clock or it that a manufacturing mark from Fed? There is another more faint mark at 4 o'clock. My guess is hot ammo and maybe over gassed as well.
Primer looks fine, but then hopefully it is a milspec primer and not subject to the usual changes we see with a hot load.

RMD

Good questions. The officer thought he had the “donut” around the extractor spring, but it turned out there wasn’t one when we looked. I believe he was probably the only shooter out of nearly a dozen who didn’t have a rubber ring of some sort around his extractor spring. The lack of the ring would of course reduce extractor tension.

As for the circular marks on the case head, those appear at random locations around the primer from case head to case head on all the unfired rounds from the same lot I inspected. They are not all in the same locations with respect to the headstamp markings. I don’t know what they are other than some artifact of the manufacturing process, but the one between the “LC” and the “08,” the lighter one at 3:00 o’clock in the photo, and the faint ones visible elsewhere aren’t ejector marks. In looking closely at the cartridge case head itself, the ejector mark appears to be a very faint burnished area directly on top of the “8”, and that would put it in the correct location with respect to the extractor.

The ammunition packaging states that it uses “mil-spec” primers, but I’ve seen much more deformation of such primers than what’s pictured above. Keep in mind as well that this exact same lot of ammunition was used in several other rifles throughout several day’s training and without causing anything similar.

Have you checked the used cartridge cases in question to see if they are oversized? This could easily be a QA/QC issue with a piece of loading machenery experiencing an issue during a production run. A slightly larger powder charge or a brass sizing/heat treating issue will cause performance variations within lotts and even within individual cases of ammunition. I've personally seen it with 22lr and USGI M882 9mm ammo.

You definitely do not have an extractor tension issue. In fact, I'm rather impressed that the extractor managed to rip off that much brass off the rim. I would have expected the extractor to break after one or two of those. This is one heck of an extractor.

And not all extractors need that donut. I replace all my bolt springs in my ARs with CS springs and eschew the donut.

The one word that comes to my mind is "overgassed." Add some weight to the BCG. I do that for my match AR because the load is so hot. Adding weight to the BCG retards the rear travel enough to allow the case to come off the walls of the chamber.

quote:

Originally posted by SgtGold:
Have you checked the used cartridge cases in question to see if they are oversized?

Yes. The one pictured easily slides into and out of a Dillon chamber gage. I also tried a couple of IMI cases that I had fired in my Tikka and they seemed to fit about the same.

NikonUser, are you referring to adding weight directly to the BCG, or just using a heavier buffer? I didn’t think to ask him if he’s using one of the lighter than normal bolt carriers, but it’s possible.

as you noted, the primer is exhibiting no high pressure signs.


It is possible he got some wonky ammo that is giving an unusual pressure curve, you swap to different ammo fixing the problem would suggest that may be the case.


Or his gas port may be dramatically oversized. Or perhaps it is that action spring. Easiest thing to do first would be to swap in a good action spring from a known quality manufacturer.

quote:

Originally posted by sigfreund:
NikonUser, are you referring to adding weight directly to the BCG, or just using a heavier buffer? I didn’t think to ask him if he’s using one of the lighter than normal bolt carriers, but it’s possible.

Yes, add weight to the BCG. I do that using the CWS from David Tubb, it comes with a insert and a heavy insert. I use the heavy insert on my AR-10 and my match AR.

It seems he's discontinued that product as I can't find it on his site. But to me that would be, by far, the easiest fix for that rifle.

quote:

Originally posted by NikonUser:
It seems he's discontinued that product as I can't find it on his site.

So it seems. Any other thoughts in that vein?

quote:

Originally posted by NikonUser:

The one word that comes to my mind is "overgassed."

I think over-gassed is correct. The chamber pressure had not dropped while the DI bolt was hit with high pressure. The dwell time may be off with 223 ammo due to the location/size of the gas port versus the length of the gas tube.

Bill

quote:

Originally posted by MrMcGoo:

quote:

Originally posted by NikonUser:

The one word that comes to my mind is "overgassed."

I think over-gassed is correct. The chamber pressure had not dropped while the DI bolt was hit with high pressure. The dwell time may be off with 223 ammo due to the location/size of the gas port versus the length of the gas tube.

Bill

Then why would the rifle run better with 5.56 ammo?

quote:

Then why would the rifle run better with 5.56 ammo?

The 5.56 ran better because the cases were annealed and thereby reduced adhesion to the chamber at the neck. The OP assumed that the annealing had been buffed, i.e., he assumed facts not in evidence.

Federal would never waste the effort to shine annealed cases. NATO 5.56 is annealed for a reason and I suspect the results from this situation illustrate why the military spends the money for higher quality ammo.

Bill

PS: On further thought, bottle neck cases are always annealed. However, there can be differences in powders used, annealing techniques and case thicknesses.

Remington 223 has lower pressure limits (~55K psi) while 5.56 has higher pressure limits (60K psi.) Higher pressure cases are frequently built differently to accommodate the higher pressures.

B.

This message has been edited. Last edited by: MrMcGoo,

quote:

Originally posted by sigfreund:

quote:

Originally posted by NikonUser:
It seems he's discontinued that product as I can't find it on his site.

So it seems. Any other thoughts in that vein?

I did find it on the site but it says it can't be ordered. Maybe call them, or try making one. I would look at a heavier buffer, maybe. Anything to add weight and retard unlocking.

Again, thanks for all the comments.

Yes, bottlenecked cartridge cases are annealed as part of the manufacturing process, and we see the discoloration on military style ammunition because, unlike commercial users, the military doesn’t care about it. I don’t know what would be involved in removing the discoloration because I’ve never attempted it myself, but I suspect it’s just some sort of polishing process by tumbling in an appropriate medium. In any event, I did make an assumption: That anyone at all familiar with ammunition manufacture would be well aware of the fact; shame on me.

Although American Eagle AE223 ammunition usually uses cases that have the 223 headstamp, the lot in question here was loaded in Lake City 5.56 brass with the annealing discoloration removed, as noted above. That might have had something to do with the issue, but evidently not because it increased pressure per se.

I checked with the officer and he hasn’t had a chance to try other 223-spec ammunition, but I’ll be monitoring the situation. I’ll have to ask him about his barrel and whether there’s any chance the gas port could be oversized.

Yes, annealing is done at the end of the process in forming cases. When I get Lapua virgin brass, you can see the annealing discoloration left on the case.

I anneal after every firing and then I resize/decap and tumble my brass. The annealing discoloration from my annealing process is all gone after the tumbling.