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Damaged brass / headspace / case separation

A

Amateur_Gardener

Active member
Hi all

I wondered if anyone has any knowledge or experience of intermittent brass damage or case separation issues?

A recent range visit has concerned me. The attached photo shows three 8x57 cases. All fired from the same rifle (a 1942 JPS with a good bore). All first use from the factory.

The case in the middle is a S&B 196gr FMJ. As you can see, there is a deep cut/ring around the base.

The case on the left is another S&B 196gr FMJ from the same box. I have another 20 or so from that range visit that look identical. I.e. a tiny ghost of a ring, but nothing untoward and pretty similar to my other centrefire fired brass of various calibres.

The case on the right is a PPU 198gr FMJ. It is virtually unmarked. As are four other PPU cases fired on the same day.

Does anyone have any thoughts on whether this is likely to be an issue with the rifle (e.g. a developing headspace problem) or could it be a one off issue with the quality control of that single S&B case/round?

I can either keep shooting and see if the issue repeats (hopefully without damaging anyone or anything), or get the rifle to a gunsmith ASAP for a detailed check of the chamber. I don't want to do this unless it's necessary though as I only know of one specialist UK gunsmith that I would trust to really know their stuff on Mausers and they are quite a long way from me.

One other point that may be relevant is that the rifle was proofed only a few years (and very few rounds) ago with no issues and is carefully maintained.

I did a search beforehand and whilst there were a few headspace threads, nothing quite like this that I could find. Likewise, posting in this section due to the vintage of the rifle but mods please feel free to move it to a more appropriate place if preferred.

With thanks as always.

AG
 

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You need to know whats going on with the middle case. Cut the case down the middle
Lengthwise till you have sawn the slit past the expansion mark then cut that portion off.
Now you can see whats going on within the case. You will probably see a thinning of the case wall at the expansion mark. Could be a hot round ( flattened primer) or possibly a deviation in manufacturing tolerances. Smaller than SAAMI minium.
 
Is it just me or are those necks also a bit sooty? Normally I wouldn't get too freaked out by that, but in conjunction with the other stuff here that's something to look into as well.

How do the case heads / primers look?

Do you have any of the unfired cartridges?

What are the fired brass dimensions? Any indication of it growing/stretching/flowing in ways it shouldn't?

That center case - is that an actual crack I'm seeing in the case, or is that just a ring of soot on it? Does that ring scratch off with a thumbnail, or is it an actual crevasse in the brass itself?
 
Thank you very much for the replies and sorry to be slow to respond in turn. I got some feedback that I needed to do a bit more parenting and a bit less shooting!

However, I managed to get away for half an hour earlier today to further my investigation. I haven't managed to cut the case in half - that's next on the list - and in fact the primer seems jammed pretty solid in the case, which may be indicative of something I suppose.

Heads and primers otherwise look normal but I'm no expert.

The 'ring' is a crack. The case is almost cut through and using a bent paperclip inside the case one can feel an internal break or ridge.

I measured the case length of every piece of spent brass I fired from that rifle, that day. I then graded each case on a scale of one to three; one being pretty much unmarked (e.g. the PPU case in the photo from the original post) and three being a cut through case like the middle one in the photo. Two being a clear ring but without cut through.

The S&B cases ranged from 57.23mm to 57.52mm long. Grade one cases were almost exclusively at the shorter end of that scale. Grade two and three cases were very much at the other end, with the damaged case from the photo the joint longest at 57.52mm, along with a couple of less damaged grade two cases.

The PPU cases ranged from 56.99mm to 57.19mm long and all were graded one.

I compared the fired cases to ten unfired cases. I only had S&B; no PPU. They ranged from 56.82mm to 56.96mm long, with most at the lower end of that range.

The width of all cases was consistent with the fired and unfired brass at 11.70mm at the point where the ring appears on the damaged case.

It seems that case expansion/lengthening is the issue. But is it a question of hot loads in the S&B, a headspace or other chamber problem with the rifle, defective brass, or something else... possibly cutting open the case will give some idea around the brass itself.

Having looked at the SAAMI specifications, it appears (to my untrained eye) that the minimum total case length is 56.965mm. However, many of the unfired S&B cases were about 0.15mm shorter than that minimum. Perhaps there's my answer.

Any further thoughts very gratefully received.

All the best

AG
 
Have you checked headspace yet? If you're getting that kind of brass flow that's the first thing I would check.

Also it's not the total cartridge length you need to worry about as far as case stretching, it's the length from the base of the cartridge to the beginning of the bottleneck. If the brass is flowing forward it's to fill in the space where the shoulder of the case isn't butting up against the matching surface in the chamber. I've accidentally trimmed plenty of case necks below the spec, especially when converting one caliber to another, and it's not really a problem as long as you've got enough case neck to hold the bullet.* It can get a bit more complex than that if you're talking about reloading and full-length resizing, but that isn't really the issue here since this is all new ammo.

If you don't have headspace gauges handy, I'd at least measure the distance from the top of the shoulder to the base of the cartridge on an unfired round and compare to one of the cracked ones. That can hopefully at least point out if there's something really crazy going on.

*edit: well, not a problem for safely shooting the gun. If you're trying to make small holes close to each other from far away, neck tension is something you need to worry about. Not so much when hacking a few .30-06 cases into 7.65 Mauser just so you can get a gun shooting to say you did it.
 
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Got it on both counts, that makes sense and is super useful.

I will measure as you suggest tomorrow.

I think I'm going to have to order the headspace gauges and work out how to use them.
 
Amateur_Gardener said:
Got it on both counts, that makes sense and is super useful.

I will measure as you suggest tomorrow.

I think I'm going to have to order the headspace gauges and work out how to use them.
Click to expand...

You can really get away with one if you're trying to be cheap. Just get the "FIELD" gauge. That's enough for your purposes. It's basically the max safe gauge. The others are the min and max spec gauges, but field is the one that takes into account the gun not being factory new.

As for how to use them, it's simple. Take the bolt apart and then put just the bolt body in the gun. Put the gauge on the bolt like it's a round - so sitting under the extractor. That's important, you need to make sure you're not resting the gauge against the face of the extractor. Try to close the bolt. If it closes all the way without resistance, the gun is out of spec and you shouldn't fire it. If the bolt stops short of locking up, it's in spec (well, at least not unsafely out of spec - again, FIELD gauges are out of spec by definition but show an acceptable amount of wear). Don't try to force anything, if the bolt is going to close you'll be able to close it with light pressure from a single finger.

edit: that said, if you get into 8mm mauser in general a full set of gauges isn't a bad thing to have. Go gauges measure the minimum headspace - the bolt should always close on one. Nogo, as you might have guessed by now, measures the maximum factory headspace. You should not be able to close a gun on a nogo gauge, but again, these are old guns so if it fails that the field gauge is the final arbiter.

I own all three. I use the field gauge all the time, I use the nogo every now and again, mostly just to see how close to factory spec the guns that passed the field are. I don't think I've ever used the go gauge, except maybe once just to prove to myself that the theory worked. It's in a drawer, I think I look at it once every five years and go "oh yeah, that thing's in here." Absolutely necessary if you're installing barrels and doing other real gunsmithing, though.
 
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Ideal, thanks Cyrano, that's exactly what I needed.

I'll get at least the field and no go gauges on order.

If it's of interest, I measured some cases this morning. I took three measurements. The ones marked with an asterisk and a cross inside a circle on page 250 of the SAAMI specifications document here: https://saami.org/wp-content/upload...99.4-CFR-Approved-2015-12-14-Posting-Copy.pdf

Basically, from the head of the case to the shoulder angle, the mid-point and the neck angle.

The fired, damaged S&B case measured 46.51mm to the shoulder, 47.92mm to the mid-point and 49.24mm to the edge of the neck.

A fired, undamaged PPU case measured 46.65mm, 47.84mm and 49.08mm respectively.

An unfired S&B case measured 46.63mm, 47.89mm and 49.09mm respectively.

So there appears to have been some S&B expansion, but not by a huge amount.
 
If your bolt matches and that middle S&B case was the only one exhibiting an incipient separation, you're probably okay. I'd check the headspace anyway, though.
 
Does the bolt match? Is the chamber enlarged toward the rear? Is the chamber out of round? Does it headspace on a FIELD gauge? S& B British 303 is garbage and I avoid it due to cheep brasss. Fire PPU or military brass after checking the rifle. Here is an old post:
www.k98kforum.com

How do I headspace this rifle

I have a Czech 98, the prior owner was a tard that’s completely pulled it apart and lost parts and pulled the barrel from the action and sporterised it, how do I headspace the barrel? What equipment do I need?
www.k98kforum.com www.k98kforum.com

I have had splits with old brass, but never head separation like that on any of my mausers. But all mine pass a field gauge. But the Turks have generous chambers and still nothing like you show. I see that with Enfields generally beat SMLEs with reloads or poor cheep ammo.
 
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Thank you for the further replies and the link to that additional thread. Much appreciated.

The bolt does match but I suspect it has been renumbered to do so, possibly whilst in Israeli service, possibly at some other time.

I have both a no go and a field gauge on order and will put an update here based on what I find when they arrive. I appear to have been a victim of drop shipping though so even though the items were apparently in stock on the website, the email confirmation now says they are back order items. So who knows when they'll be delivered. 8x57 headspace gauges seem to be a pretty niche item here in the UK and very few places carry them. Even Brownells is out of stock.

In terms of chamber enlargement or being out of round, I will need to do some research to understand what signs I need to try to spot to know.

That's interesting in terms of your experience of S&B .303 British. I have also found it to be pretty poor (well inaccurate, and often showing case rings albeit not as substantial as the 8x57 example I posted in this thread) but I put it down to the rifle I have used it with, which is a two groove club gun that I assume may not have been particularly cherished.

I'm also in the market for my own .303 Enfield, assuming my certificate comes back from the police with a positive response, but I intend to really take my time and find a mint one.

Certainly, in future I'll probably aim to avoid S&B in my centrefire rifles. Not ideal as I have a fair stock!

Thanks again.

AG
 
Hello everyone

A quick update on this one for those that helped me out or, indeed, anyone else interested!

The bolt closed comfortably and with no pressure on both the no-go gauge and the field gauge. So I think that I have found my problem.

Off to the gunsmith she goes to see if she can be saved...

AG
 
Glad to see you figured out the problem. I once had a Yugo M76 in 8mm that would swallow a field gauge like it wasn't there, but interestingly there were no signs on the empty brass. Good luck getting it straightened out.
 
Amateur_Gardener said:
Hello everyone

A quick update on this one for those that helped me out or, indeed, anyone else interested!

The bolt closed comfortably and with no pressure on both the no-go gauge and the field gauge. So I think that I have found my problem.

Off to the gunsmith she goes to see if she can be saved...
Click to expand...
If you reload the headspace issue can easily be corrected by backing off the sizing die until the bolt won't close on a no-go gauge.
A gunsmith will have to set the barrel back a full thread so that the sights are about 5 degrees shy of top dead center then torque the sights TDC and recut the chamber. Not a cheap thing to have done.
 
Thanks everyone, very much appreciate the ideas and good wishes.

Unfortunately, reloading isn't an option for me at the moment, although I'm keeping all my spent factory brass in the hope that one day it will be.

I appreciate the description of the work involved as I had no firm idea. I recognise that rectification won't be cheap - I have been quoted circa £250 to £300 - but I'm pretty determined to keep this one in service if I can. There seem to be fewer and fewer serviceable German K98ks in the UK these days. A mini-boom in the collection of second world war items in the last few years combined with the constrained position on civilian ownership of firearms seems to be driving lots of examples that do come up into the hands of deactivators. It's a huge shame and I couldn't bring myself to do it to this old girl!

On the bolt, it's a mismatch so I would be open to a replacement. However, as that will be a controlled item here, that in itself adds complexity and I think would need to be arranged via a firearms dealer.

AG.
 
Amateur_Gardener said:
Thanks everyone, very much appreciate the ideas and good wishes.

Unfortunately, reloading isn't an option for me at the moment, although I'm keeping all my spent factory brass in the hope that one day it will be.

I appreciate the description of the work involved as I had no firm idea. I recognise that rectification won't be cheap - I have been quoted circa £250 to £300 - but I'm pretty determined to keep this one in service if I can. There seem to be fewer and fewer serviceable German K98ks in the UK these days. A mini-boom in the collection of second world war items in the last few years combined with the constrained position on civilian ownership of firearms seems to be driving lots of examples that do come up into the hands of deactivators. It's a huge shame and I couldn't bring myself to do it to this old girl!

On the bolt, it's a mismatch so I would be open to a replacement. However, as that will be a controlled item here, that in itself adds complexity and I think would need to be arranged via a firearms dealer.

AG.
Click to expand...

Your best bet is probably going to be to have a turn shaved off the barrel and then get it timed correctly and the chamber re-cut, as already discussed above.

Swapping bolts is the easiest and quickest way to take care of this, but it involves having a supply of bolts in front of you that you can swap in and out while you try things with the gauge. To give an example, back when Turkish Mausers were being imported to the US and cost about $70 at a sporting goods store, I'd go there with a gauge in my pocket, find a rifle that I liked, and then ask to see a few more and just move bolts around until I got a combo that worked. Store clerks didn't care, once it was a done deal that I was buying a gun they were more than happy to pull some extra guns for me to paw over. One who actually knew what I was doing just brought me a plastic bag full of bolts he snagged from the back so he could avoid carrying a dozen rifles out front.

Which is all to say, if you've got the stuff on hand it's trivial and way easier than having a gunsmith work on it. But if you're in a situation where you don't have a bunch of bolts on hand, or worse they are a controlled part? The gunsmith option will do it with what you have in your hands right now.

Frankly 300 pounds isn't a bad price for that kind of work. Maybe a bit more than I'd put into a bolt m/m in the states, but different contexts mean different priorities.
 
Just a reminder -- when using headspace gages, bolts need to be stripped. Even the extractor should be removed, preferably. Chamber, gage, bolt face, locking lugs and locking recesses should be squeaky clean and free from oil. ,

With the gage inserted in the chamber, it should be "felt" with the tips of the index finger and thumb on the bolt knob.

To do otherwise is akin to using a micrometer caliper as a C-clamp.
 
If you have the barrel set back the breach face should be machined back .0052. Thats
52 thousandths. The way it is calculated is the threaded shank is .625 long ÷ 12 threads per inch= .0052. One complete revolution to get everything back top dead center.
 
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