Case separation, rough chamber, brittle cases?

I had initial thoughts of brittle brass due to the case separation. But after going back through the spent cases, I then thought I may have a rough chamber.

Now, I'm unsure...

We were sending a few 223 rounds downstream on the weekend. Using Belmont 62gr FMJ (Hornady cases) and some PMC 55gr soft points
Marlin 223 and a Bergara 223 single shot.
The Marlin gave us a few misfires with the FMJ, 6 or so out of 80 odd rounds, no issues at all with the PMC. FMJ rounds fired later when run through the Bergara. No markings on cases.

The Bergara was originally a 222, rechambered at some point to 223.
It fired everything we fed it, Belmont and PMC. Thirty or so rounds in, I opened it up to reload and lifted out 1/3 of a case. Uh oh.. I put the rifle aside and spend a few hours with the kids on the .22s.
That evening we extracted the rest of the case with a cleaning rod, it came out freely, no resistance at all. What a relief.
I checked the chamber with a torch, nothing out of the ordinary was obvious. (It was dark too though).
So the next day we put a few more rounds through the rifle. Twenty rounds in and I saw another partial separation when extracting a spent case.
Swapped onto the PMC rounds and 6 rounds set free no issues at all. (Looking closer tonight two PMC cases have a fine ring mark showing)
Cleaning the rifle after the weekend and giving the chamber a good scrub, the machining marks were obvious but there but there is no lip or indent where the cases have been marked and separated. (I think I'll get the chamber polished though)


Looking back through the spent cases tonight and there is an obvious line on a lot of the cases. And a third cracked case I didn't see while shooting.
I am not a reloader and I am an average armchair internet researcher so I am uncertain about this.
In hindsight I should have examined the chamber more closely before cleaning. But I was thinking more of a fault with the cases at that point. But all the cases are marked in the same place so now the chamber appears to be the culprit.
I had previously only put a few sighting rounds through the Bergara myself. So this issue hasn't been apparent.

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Possibly excess headspace, have a Gunsmith check it, ideally one that is familar with single shots as the are a few quirks compared with a headspace check on a bolt gun.

The mark in the chamber is a complication to your observations but I’d bet you have excessive headspace

If it's belmont black, I've had the three case head separations over the years with it but to be fair I've used several thousand. The ammunition is made using fired ex military adi brass typical headstamps 16 and 17 and evidently that which has been through a machine gun can get a bit stressed. As yours is hornady I'm not sure if this applies.

Another vote for excessive headspace.

Greetings,
Assuming that the rounds you are firing are not reloads the problem is excess headspace. The fact that the Marlin had some missfires makes me wonder if there is an ammo problem as well. Are all the rounds factory ammo and not rounds with remanufactured brass?
Regards Grandpamac.

"I checked the chamber with a torch, nothing out of the ordinary was obvious."

Its hard looking at an image of a chamber
BUT that looks like pretty rough chamber reaming to me
So I'm thinking headspace as per all the previous posters but also the chamber is out of spec further up the case
I'm wondering how they dialed in the barrel to open the 222 chamber up to 223
The quick and easy way is not usually the correct way and if the Bergara barrel was a little out of concentric originally the quick and easy way will have likely made things vastly worse

Cheers guys.
I appreciate all the feedback, even though it isn't what I was hoping to hear.
Rifle will be off to a gunny in a few weeks. Here's hoping it can be remedied.

my old eyes see something that MAY be causing issue..... the last bit of chamber is smooth...the front is not...so a case when fired will expand and grip the chamber walls...but the rear bit can move...so with chamber maybe a tiny bit too long,if the front gripped first,then the rear moved till rear stopped by face of action..the bit of brass just back from the line will get stretched....
as you not intending to reload.....the now stretched brass isnt an issue as such but broken cases will be....maybe try some steel case barnaul????? it may be more forgiving????
keep us informed as to what gunny has to say PLEASE.

Quote:

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Originally Posted by Micky Duck

my old eyes see something that MAY be causing issue..... the last bit of chamber is smooth...the front is not...so a case when fired will expand and grip the chamber walls...but the rear bit can move...so with chamber maybe a tiny bit too long,if the front gripped first,then the rear moved till rear stopped by face of action..the bit of brass just back from the line will get stretched....
as you not intending to reload.....the now stretched brass isnt an issue as such but broken cases will be....maybe try some steel case barnaul????? it may be more forgiving????
keep us informed as to what gunny has to say PLEASE.

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This makes sense and could explain why the lines/cracks are all in the same place. Definitely food for thought, cheers MD. Will report findings.

See if the GS will let you watch as he checks headspace. Its done a bit different on a break action. He should first use a feeler guage to measure the "gap" between the breech face and barrel, then use the headspace guages. If he/she doesnt do this I'd be getting another opinion. Cheers

And if the headspace is out, or the chamber reamed out of concentricity, all is not lost. Have it reamed out properly to a 22-250.

Gibo will love me for saying it...but 22hp savage is option too..... but totally unpracticle for a non reloader LOL.

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Originally Posted by Husky1600

And if the headspace is out, or the chamber reamed out of concentricity, all is not lost. Have it reamed out properly to a 22-250.

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Have Ruger Mk1 in 22-250 already. but..

Greetings again,
From the photograph the edge of the breal looks like classic head separation from excess head space. The crack starts from a groove on the inside of the case and progresses to the outside. This usually takes more than one shot, mostly several. For this reason I wonder if you are absolutely sure that the cartridges are not reloads. If they are factory new then the headspace is likely to be grosly excessive or the rifle is not locking up securely. In any case best not fire it until it is sorted.
GPM.

Quote:

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Originally Posted by grandpamac

Greetings again,
From the photograph the edge of the breal looks like classic head separation from excess head space. The crack starts from a groove on the inside of the case and progresses to the outside. This usually takes more than one shot, mostly several. For this reason I wonder if you are absolutely sure that the cartridges are not reloads. If they are factory new then the headspace is likely to be grosly excessive or the rifle is not locking up securely. In any case best not fire it until it is sorted.
GPM.

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All but one of the damaged cases is Belmont ammo, so could well be reloaded. The other case is a PMC, we fired a dozen of them with no cracking or marks showing.

I'd guess Belmont would take these (remanufactured) cases back to absolute minimum SAAMI to guarantee chambering in all firearms but that shouldn't produce a case separation in a single firing unless the headspace is -grossly- excessive as GPM said.

I too look with interest as to the gunsmith's opinion.

Quote:

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Originally Posted by Tentman

See if the GS will let you watch as he checks headspace. Its done a bit different on a break action. He should first use a feeler guage to measure the "gap" between the breech face and barrel, then use the headspace guages. If he/she doesnt do this I'd be getting another opinion. Cheers

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Be interesting to get an actual headspace measurement, i.e. the length of the chamber in the barrel and not relative to the action face. Possibly the case is sitting on the extractor when chambered, and it's held there firmly enough to allow the primer to be set off by the firing pin when in reality the case should be sitting on it's shoulder and the extractor not doing anything until it's time to pop the fired case out. Needs a good look at before I'd fire it with my face next to it...