Blown Primers, AR 15

[Shredla]

Looking to troubleshoot a family members rig, upper consists of:
Criterion hybrid midlength 13.9 223 wylde chambering
BCM bcg
BCM upper receiver
BCM handguard
Geissele super 42 spring with an H2 buffer
Sitting on a Radian ADAC.

We've ran a few different rounds through it , id estimate the current round count is 200+/- and im aware of 4 or more instances where a primer has blown out of the back of the casing and caused a jam. 2 or 3 times the primer got lodged toward the front of the bolt face and we had to mortar the rifle, today a primer got stuck up near the gas key and we had to remove the castle nut and drift the BCG out the back.

Today's blown primer came out of a factory sealed Federal American Eagle xm193 5.56

If its a head space issue is there anything that can actually be done? Or would he just need to buy a new bolt sight unseen and hope it has a different tolerance than the original?

 

[Shredla]

Summoning the wisdom of @AR15barrels

 

[Markbsae]

What's the ejection pattern tell you about the gassing?

 

[Shredla]

What's the ejection pattern tell you about the gassing

3 to 4 o'clock consistently.
Yesterday after the has a primer get stuck up by the gas key at the range (burro canyon) I checked all of his brass and found 3 rounds completely missing the primer and a 4th round woth the primer protruding 75+ % of the way out of the rear of the primer pocket.

Again, this particular day he/we were shooting a factory sealed box of Federal's American Eagle xm193, but he has also had primers pop and cause jams from other manufacturers. Those 4 spent casings I found with missing or protruding primers came out of a sample size of about 50 rounds fired that day 4 in 50 rounds had it happen.
I've never had a blown primer on anything that wasnt a bad hand load.

 

[AR15barrels]

Today's blown primer came out of a factory sealed Federal American Eagle xm193 5.56

If its a head space issue is there anything that can actually be done? Or would he just need to buy a new bolt sight unseen and hope it has a different tolerance than the original?

Any chance this is older ammo from the early 2010's?
Lots of problems with that ammo from that time period.

If not, it's still an ammo problem if the gun passes headspace checks.
You mention all the parts in the build but you don't mention if the bolt headspaces correctly to the barrel.
If it fails headspace, the first thing you do is try a different bolt.
If multiple bolts fail headspace in a barrel while those same bolts pass headspace in a different barrel, the barrel should be replaced.

 

[Shredla]

Any chance this is older ammo from the early 2010's?
Lots of problems with that ammo from that time period.

If not, it's still an ammo problem if the gun passes headspace checks.
You mention all the parts in the build but you don't mention if the bolt headspaces correctly to the barrel.
If it fails headspace, the first thing you do is try a different bolt.
If multiple bolts fail headspace in a barrel while those same bolts pass headspace in a different barrel, the barrel should be replaced.

@AR15barrels do you know of a specific gauge from brownells or midway you would recommend to check head space? Also, is there any fix for head space issues? Or do we just need to order another bolt and hope that it has a slightly tighter/looser tolerance the the original BCM. Bolt?

 

[Shredla]

Any chance this is older ammo from the early 2010's?
Lots of problems with that ammo from that time period.

If not, it's still an ammo problem if the gun passes headspace checks.
You mention all the parts in the build but you don't mention if the bolt headspaces correctly to the barrel.
If it fails headspace, the first thing you do is try a different bolt.
If multiple bolts fail headspace in a barrel while those same bolts pass headspace in a different barrel, the barrel should be replaced.

Also unknown the production date but the the head stamp has what i think was L and C stamped on it with a purple dye around the primer pocket.

 

[AR15barrels]

@AR15barrels do you know of a specific gauge from brownells or midway you would recommend to check head space? Also, is there any fix for head space issues? Or do we just need to order another bolt and hope that it has a slightly tighter/looser tolerance the the original BCM. Bolt?

Maximum headspace dimension for 223 is 1.4736"
Colt uses that same dimension as it's maximum length for 5.56 chambers.

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No in-spec 223 or 5.56 should ever close on that gauge without undue force.
This is the absolute max length gauge where you would take a gun out of service if that gauge fits without undue force.
Gauging is done with the upper off the lower and the ejector removed if the gauge is not relieved to clear the ejector.
A single finger pressing on the rear of the bolt carrier group is all the force you use to attempt to close the bolt.

Never place a headspace gauge in the barrel of an assembled gun and let the bolt carrier close with the bolt release.
That's the most extreme example of undue force there is.
Any AR type will force itself to close in that condition when it would not if gauged properly.
That's also a great way to destroy gauges, barrels and bolts.

There is no user-adjustment for headspace.
The parts are either right or they are not.
Passing GO and Field gauges on a used barrel tells you if all parts are right.
Swapping multiple bolts and barrels around while gauging will let you see where the problem lies.
The problem part will be the single part that is present in multiple headspace test failures.

 

[AR15barrels]

Also unknown the production date but the the head stamp has what i think was L and C stamped on it with a purple dye around the primer pocket.

That means the cases were made in the lake city army ammunition plant.
ATK (the parent to Federal) ran the lake city army ammiunition plant under contract with the army from 2000 to 2020 when Winchester took over the contract.
Having LC stamped brass likely means the ammo is from before Winchester took over lake city as I doubt you will see LC stamps on federal ammo after Winchester takes over.