Looking for some insight here, factory loaded ammo - Federal 75 grain.  Blowing primers like it is their job on a hot chamber after 10-15 rounds.

Ammo is headed back to federal.  The ones that still have primers don't look over-pressured but I'd consider the ejector marks to be fairly strong.

Barrel / Bolt is a LaRue that are going to a local barrel manufacturer on Monday to be checked out.

From a reloading perspective I'm perplexed.  I'm not really sure where to go, is the chamber too tight, is the powder they're using too heat sensitive, not really sure.

Thoughts?

Close ups would be nice. Are those some serious swipes I think I'm seeing? Almost looks like the primers are flat, but there's no flow around the firing pin. Is one primer pierced?

Something's not right, for sure.

Is the weather hot where you're located? Is the ammo being left in a hot car, or in the sun?

It's taking a beating, Federal has tons of reviews on this ammo blowing primers, they're response is always "it's within spec".

I wish, I purposely left the ammo and gun in the shade at all times.   10-15 rounds on a hot chamber and they're done regardless of how long they're cooking in the chamber.

Only time I've ever had a similar issue was an AR15 in .223.

Had primers blowing out into the upper and lower receiver.  Locking up the bolt, locking up the firing mechanism.  PITA.  With the std. load that worked in 8 or 9 other AR15's in .223 and that I still use today 8 or 10 years later.

I ended up buying a set of headspace gauges and the bolt would barely (and I do mean BARELY) close on the go gauge.  All my other AR15's would close and still allow a small amount of bolt movement if I wiggled it with my fingers.  I went through all mine and found an upper that would close on the no go gauge (but not on the field gauge).  I swapped bolts between the two and got that little bit of movement with the 2nd bolt that I didn't have with the Go gauge in that carbine that had been very tight.  After that not a single blown out primer, no issues 10 years later.

If there is a way you can check headspace, see how much movement/wiggle you can get out of the bolt with the Go gauge chambered.

In spec, sometimes, can still be an issue.

Or change ammo and see if the problem goes away - doesn't mean the rifle isn't contributing to the issue, just means ammo is different, one bullet weight/style or the next in different rifles.

Good luck with it.

Had you worked up handloads for this gun? If so, where did you start seeing pressure signs compared to published data?

It's most likely something going on at Federal's end, considering the number of complaints.

I'm taking the barrel and bolt to a barrel manufacturer on Monday to have it checked out.   Unfortunately Federal is about the only one making ammo for these right now as they designed the caliber and it's relatively new, so there aren't a lot of ammo choices.

I'm hesitant to load anything for it if it's blowing primers on factory loads.

I would think they'd want an assembled rifle if you're having them check headspace.

If he has rifle length gas I don't think this is the issue. I mean, I agree with your explanation of what is happening but plenty of people have shot this ammo and OP has the worst pressure signs I have ever seen in 224. It has to be some headspace.chamber, etc issue.

Federal loaded all of their Valkyrie ammo super hot. OP's gun exposes why this was a bad idea.

Barrel is a rifle gas and the buffer setup is rifle as well.  Local manufacturer said just bring the bolt and barrel, will update tomorrow with what they have to say.

This thread might lend some wisdom...

Never had much luck with Federal rifle brass, primer pockets loosen real quick to the point where all "FC" range pick-ups go in the scrap bucket.

Because of stories like yours that I have read more than a few times, I had low expectations when I decided to reload Federal GMM (168 grain) brass for my 308...  My experience has been very good with "FC 308 WIN" brass.  I bought a case of FGMM for a precision 308 bolt gun that I got...  shot the ammo and saved the brass...  I was going to be getting back into reloading after a long hiatus & wanted some brass to tinker with before reloading with my "good brass" (200 pieces of Lapua 308 brass).  I have developed 2 loads and am in the middle of developing #3...  I have 40 pieces of this brass that I am using for just load development.  I have 10 firings on this brass so far and haven't had a single problem.  Primer pockets are still going strong...

Blanket statement, I've reloaded a ton of FC brass at 5.56 pressures and never had a problem.  Primer seat easier but they aren't blowing out like these even with multiple firings.

Gunsmith was able to point out a multitude of clear issues with the barrel, it's on it's way back to LaRue.

Not saying the ammo isn't a suspect too but the barrel certainly didn't help things.

Federal Rifle Brass is notorious for being soft with short case life.
The boys up in Anoka have had lots of issues with the 224.

There are other options for Valkyrie brass now.  Starline and pretty soon Hornady will be available.

Care to elaborate on the issues noted?

I'm sure Larue will make it right, but there seem to have been some bad reamers which made it to manufacturers and I'm wondering if there are others ghosts in the machine we are just now finding along the way.

Ream wasn't one of the issues and free bore was well within spec.  I'm hoping this was a one off issue because this barrel had every Smith in the place going WTF.

Will post an update once I know something. LaRue was easy to deal with and hopefully they make it right.

Over gassed, overpressure, something like that

The swipes could be just form the bolt moving too soon, which could be too light of a buffer, but the primers make it more like overpressure.

I had that happen with my Creedmoore because it adjusted the gas block the wrong way. Started getting swipes, and then got some pushed back primers, but then on the fourth or fifth one I lost a primer and stopped.  I fixed it by cutting the gas to zero and working back up to where it would eject and not create swipes.