Damaged brass / headspace / case separation

[R.W. Parker]

.0052. Thats
52 thousandths.

That's actually five and two ten-thousandths. Fifty-two thousandths would be expressed as .052.

But decimal places aside, take nothing for granted. Always measure from the face of the receiver ring to the inner ring with a depth mic.

 

[Amateur_Gardener]

Thanks again for the further useful information and advice. Much appreciated.

In terms of exchanging the bolt, whilst that would very much be my preferred first option I just can’t think of a way to get a bunch of bolts to try here in the UK. Even getting one would, I think, possibly have to come from the US or Germany. Still, as you say, £300 not unreasonable for this work I don’t think.

The place that I propose to use comes recommended by some other UK K98k shooters and seems to have some experience with re barrelling and and similar work on these rifles. However, I will discuss these measurements with them as, clearly, there is very little margin for error!

When originally testing I removed the extractor. Bolt closed no problem at all on the field gauge. The one time when smooth as butter was not what I wanted.

I will keep this thread updated.

In the meantime, just picked up a 1937 Portuguese contract model in super condition. Will get some photos up in the correct forum in due course.

 

[Humbarger]

That's actually five and two ten-thousandths. Fifty-two thousandths would be expressed as .052.

But decimal places aside, take nothing for granted. Always measure from the face of the receiver ring to the inner ring with a depth mic.

Right. My brain fart!

 

[Metal]

Just a word of warning about this S&B 196gn fmj ammo, I recently bought some and was shocked to find that it had up to .015” headspace in three of my rifles which I positively know have in spec chambers.
I also checked with 3 other brands of new brass and factory ammo, all having around 003” headspace in the same rifles.
This situation combined with low quality brass could be the cause of a case head separation.
Cheers all.

 

[Muncher 1953]

Just a word of warning about this S&B 196gn fmj ammo, I recently bought some and was shocked to find that it had up to .015” headspace in three of my rifles which I positively know have in spec chambers.
I also checked with 3 other brands of new brass and factory ammo, all having around 003” headspace in the same rifles.
This situation combined with low quality brass could be the cause of a case head separation.
Cheers all.

Any reports of this problem in their .30-06 ammo? (I bought some NOS for my son this summer)

 

[Metal]

Any reports of this problem in their .30-06 ammo? (I bought some NOS for my son this summer)

No sorry I don’t know about the’06.
I’ll be pulling the bullets and jamming them in the lands for firing.
I usually reload, only bought them because they were relatively cheap. Thats the catch.

 

[Muncher 1953]

I usually reload, only bought them because they were relatively cheap. Thats

No sorry I don’t know about the’06.
I’ll be pulling the bullets and jamming them in the lands for firing.
I usually reload, only bought them because they were relatively cheap. Thats the catch.

might you still have the ammo cartons, if so what’s the lot code/date? usually on the ‘tongue’ of the end flap.

Some time ago I bought a box of ‘80s 8mm boxed as “Hansen Cartridge co”, headstamp indicated manufacturer was Igman. On close inspection, several of the cases had split necks, didn’t appear to be someone’s reloads. I pulled all the bullets, dumped out the powder & fired the primers, put cases in w/my scrap brass. internet research turned up a few old threads about brittle brass in Igman made ammo.

 

[R.W. Parker]

Just a word of warning about this S&B 196gn fmj ammo, I recently bought some and was shocked to find that it had up to .015” headspace in three of my rifles which I positively know have in spec chambers.

I wouldn't be overly concerned by this. In a 98 the cases will be held close to the bolt face by the extractor, so I'd expect the shoulder to fire-form before you'd see any signs of head separation.

 

[Metal]

I wouldn't be overly concerned by this. In a 98 the cases will be held close to the bolt face by the extractor, so I'd expect the shoulder to fire-form before you'd see any signs of head separation.

The extractor does not hold the cartridge tight to the bolt face.
There is 015" clearance between the cartridge and the bolt face with the extractor in the most rearward position on one rifle I measured.
Upon firing, this would allow 015" forward movement of the cartridge before the shoulder contacts, stretching the cartridge at the base.

 

[R.W. Parker]

I'm curious as to whether you've fired any of that S&B 196-grain ammunition in your "in-spec" chambers, and if any of the cases subsequently exhibited signs of an incipient separation. Not a stretched case, but either an incipient or complete head separation.

 

[Muncher 1953]

I wouldn't be overly concerned by this. In a 98 the cases will be held close to the bolt face by the extractor, so I'd expect the shoulder to fire-form before you'd see any signs of head separation.

Following along with the OP’s original question, I realized I recently bought 2 boxes NOS S&B 8x57 JS at my arms collectors club meeting, & thought to check it w/my LE Wilson case gage for this caliber. It’s designed for unloaded cases but still shows when the shoulder has been pushed back “too far” towards the case head, possibly creating too much headspace in any given ‘in spec’ rifle. Of the 1st 6 rounds I checked, 4 were too ‘short’ ( distance from case head to shoulder datum point, not case length or overall cartridge length) 2 were right at the limit. I’ll add pix of carton & lot #s, as well as results of all 40 rounds in the next couple of days. I think I’d feel comfortable shooting the borderline rounds but not the clearly failing ones. In rifles other than a model 98, I wouldn’t risk it.

Your face, your choice.

 

[Muncher 1953]

pix added.

Because I reload, I've learned that there are some things that one can 'finesse' in terms of customizing ammunition to fit a particular rifle. I hate to toss new brass, I'll see if the marginal ones fireform OK, the 'fail' ones I 'might' test with a remote firing setup, depends on time/interest available when I think of it. Given the likely age of the ammunition, not sure if S&B would replace it, as not from a retail source. I'm thinking it more important that folks here know to look for the problem, & if the fellow I bought it from still has any more, that he may not want to sell it as shooter ammo.

 

[R.W. Parker]

pix added.

Because I reload, I've learned that there are some things that one can 'finesse' in terms of customizing ammunition to fit a particular rifle. I hate to toss new brass, I'll see if the marginal ones fireform OK, the 'fail' ones I 'might' test with a remote firing setup, depends on time/interest available when I think of it. Given the likely age of the ammunition, not sure if S&B would replace it, as not from a retail source. I'm thinking it more important that folks here know to look for the problem, & if the fellow I bought it from still has any more, that he may not want to sell it as shooter ammo.

If you're uncomfortable shooting the "fail ones", you could always pull the bullets and fireform 'em with a couple grains of Bullseye and some cornmeal. Unless, of course, you have so many 7,92x57 cases that this would be a waste of time...

 

[Muncher 1953]

If you're uncomfortable shooting the "fail ones", you could always pull the bullets and fireform 'em with a couple grains of Bullseye and some cornmeal. Unless, of course, you have so many 7,92x57 cases that this would be a waste of time...

Good suggestion, thank you.
Fortunately, I do have plenty of 8mm brass. Being thrifty, I’m more annoyed about the $40 spent on new ammo w/issues. I may run the same check on some of the new PPU 8mm I have stashed for comparison.

 

[R.W. Parker]

Given the likely age of the ammunition, not sure if S&B would replace it,

I'd be willing to bet they'd do something for you. Drop 'em a line, it can't hurt. You might be pleasantly surprised.

 

[Muncher 1953]

I'd be willing to bet they'd do something for you. Drop 'em a line, it can't hurt. You might be pleasantly surprised.

I will, once I’ve put all 40 through the gage. Only fair/professional to have data, if one is ‘making complaint’. S&B is generally regarded as producing good quality ammo (I think) but I have seen some old threads on other fora suggesting some issues w/their 9mm luger ammo, hard primers & misfires in certain particular weapons. Too easy in today’s environment to repeat half-truths, rumors & internet chatter. It ‘may’ have to do with S&B being owned by CBC, the Brazilian ammo maker, whose quality reputation isn’t quite as good. (IMO)
At the very least, I’d like to find out what month/year the lot is from, relative to CBC’s acquisition of S&B. (2009, IIRC)

EDIT:
out of the 40 rounds, only 10 ‘passed’, and those are right at the lower limit. I noticed something I’ll try to photograph, that of about 30 of 40 cases, the heads aren’t square to the body! You’d never see it w/out this type of gage, AND rotating the case in the gage, but when I do that, it’s easy to see the ‘wobble’ (even as nearsighted as I am).
I’ll try the same tests with some other brands of unfired 8mm & compare.

 

[Cyrano4747]

I wouldn't be surprised if you find a lot of ammo with that kind of "wobble." Concentricity is one of those holy grails that people who get into serious precision reloading are always chasing, and my understanding is that a lot of factory ammo uses processes that just don't control for it quite as well. Military ammo in particular is bad for this, but it wouldn't surprise me at all to find it in commercial ammo that isn't marketed specifically to precision target shooters.

 

[Amateur_Gardener]

In case it is useful, and because one or two have suggested I post it, the batch code for the rounds giving rise to the original post is 667/12.

They arrived in what I think is the latest style 50 round black and gold box.

Best

AG

 

[Muncher 1953]

If you're uncomfortable shooting the "fail ones", you could always pull the bullets and fireform 'em with a couple grains of Bullseye and some cornmeal. Unless, of course, you have so many 7,92x57 cases that this would be a waste of time...

Case Gage-CG-

lewilson.com

thinking about this some more, I ran across the printed instructions with the gage, and on the back page, in FAQ it mentions that new unfired brass measured in their gage, (designed for as-fired cases) may sit as much as .030” below the minimum step of their headspace end of the gage, adding that the brass manufacturers will do that when the caliber has great head space variation in the weapons pool. I’ll have to see if I can find a proper depth mike to confirm, but reading that changes my thinking about what my 2 boxes of S&B 8mm look like in their gage. I suspect that R.W. Parker is correct about these rounds being just fine, & will fire form acceptably & safely.

Completely different from the OP’s issue, that brass pic in post#1 is scary!

 

[Muncher 1953]

Case Gage-CG-

lewilson.com

thinking about this some more, I ran across the printed instructions with the gage, and on the back page, in FAQ it mentions that new unfired brass measured in their gage, (designed for as-fired cases) may sit as much as .030” below the minimum step of their headspace end of the gage, adding that the brass manufacturers will do that when the caliber has great head space variation in the weapons pool. I’ll have to see if I can find a proper depth mike to confirm, but reading that changes my thinking about what my 2 boxes of S&B 8mm look like in their gage. I suspect that R.W. Parker is correct about these rounds being just fine, & will fire form acceptably & safely.

Completely different from the OP’s issue, that brass pic in post#1 is scary!

I finally got a chance to sit down w/case gage & check some various unfired loaded ammo. ww2 German brass & steel cased rounds from 1938 & 40, P442(38) P162, 369, 249, some Hirtenberger rounds from ‘83, Romanian labelled m75 marked nny 92(=PPU in Serbian) all sat low in the gage, making one suspect out-of-spec ammo. By contrast, the 2015 dated rounds of PPU (in the blue ‘Rifle Line’ box) and the 1970’s Remington rounds sat noticeably higher in the gage.

The OP had an issue with his rifle & headspace, but when I first read about the s&b ammo, I was concerned. From my crude measurements, I conclude that this is normal, & may be the difference in CIP vs SAAMI specs. The ‘short’ rounds were all european manufactured, the longer, US…….well except for the 2015 PPU. possible they make the US bound stuff to different specs than Euro-bound? PPU headstamp vs nny, different markets, different specs?

one thing about the particular batch of s&b I checked was that the heads of the cartridges wobbled when I rotated them in the gage, and almost none of the other 6 boxes of any brand showed the same characteristic. head runout? Catrtridges aren’t turned, they are progressively stamped. I suspect worn tooling on that lot of s&b, & that it will fire form acceptably when I shoot it.