Question for .223 / 5.56 reloading gurus. (Case dimensions, specific malfunction issues)

[VolksDragon]

So I have this .223 ammo conundrum, and I'm hoping the reloading collective can lend me some assistance in getting this sorted out.

During the 2012/13 craziness, I bought about 15k rounds of commercially-reloaded .223 in bulk during two of the popular group buys from Precision Cartridge. I eventually received it in good order, and after sharing a bunch of it with friends and others who jumped in with me, I added about 4k rounds of it to my own ammo stash, and forgot about it.

I recently began shooting it during some range days, and noted that about 1 in 15-20 rounds will fail to extract, and will result in a solid in-battery lockup with the fired case stuck firmly in the chamber. This often requires total disassembly or a considerable "mortar" style maneuver to clear them. This has occurred in 4 separate known-good ARs from Daniel Defense, Stag, Palmetto and Sig, with both carbine and mid-length gas, 16", 11.5" and 10.5" barrels. The extracted brass doesn't show any case head separation or other obvious deformities, (although I don't have a fired sample at the moment).

I've narrowed it down to the ammo, so here's my real question: Is there a specific dimension of the cartridge I can check for in this instance that might be contributing to the malfunction? (Shoulder, brass length, diameter, deviation from OAL?) I'd love to just measure and weed out the offenders and pull them so I can re-use the components, but I'd REALLY like to avoid pulling the entire lot if I can, since I'm sure some of them good to go. I measured a sample of 40 rounds out of the lot, and they all varied from 2.219 to 2.232 OAL, with brass at 1.743 to 1.752. Headstamps are a mix of LC, Winchester and PMC.

Additionally, as mentioned, many thousands of rounds from the same lot are out there with some friends, so if I can nail down a solution, it will help many of us.

Any thoughts or wisdom on this? Anything else to look for or consider?

[sellersm]

Got a case gauge? If so, run them through it. If not, get one and use it.


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[VolksDragon]

Got a case gauge? If so, run them through it. If not, get one and use it.


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Not yet, I'll get on it. If the dimensions are good to go, any idea what might be causing this?

[sellersm]

I would recommend the Sheridan Engineering case gauge that’s ‘cut away’ so you can visually see what’s wrong.

My guess? Shoulder setback issue.


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[VolksDragon]

I would recommend the Sheridan Engineering case gauge that’s ‘cut away’ so you can visually see what’s wrong.

My guess? Shoulder setback issue.


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Excellent. Thanks for the wisdom, good sir!

[Hoser]

Most likely they didn't bump the shoulder back enough or too much crimp caused a slight buckle at the shoulder/body junction.

[sellersm]

Just to clarify, this is the Sheridan product I was referring to: http://www.sheridanengineering.com/index-2.htm

[gat_wrench]

Late to the party here, but I just noticed this thread. A friend of mine was shooting some of this ammo about two years ago, and having similar problems. Occasionally, though, he had cases tear in half and leave the front half stuck in the chamber as well. We ended up finding that his failures were consistent with ammunition that has been roll-resized slightly out of spec... an improper rolling procedure can case a lot of issues with FTE's and case separations. Precision Cartridge states on their website that they roll-size their re-manufactured ammo. You may or may not find issues when gauging this ammo, but I think it will continue to give you problems, and I don't think there is a "solution". Just my two cents, though...