Cracked cartridge case - Mosin Nagant

D

divil

New member
I have a Finnish M39 Mosin Nagant that I bought from http://www.gunsnammo.com/ a while back. I have only fired a handful of rounds through it, and I took the first few empty shells along with the rifle to my local gunsmith to have it checked for safety. He didn't have the right headspace gauge for my rifle but from looking it over and examining the shells, he said it seemed OK.

So yesterday I took it down the rifle range again after a few months of a break, and the second round I fired, the shell was cracked near the shoulder. The crack was longitudinal, and just a few millimetres long. There were no signs of any cracks near the rim.

Is this dangerous? I was afraid to fire any more once I saw this, but maybe it's normal for cracks to appear on the shoulder of the cartridge, I don't know. Any advice would be greatly appreciated!
 
Alot of surplus ammo is made to poor specs and/or degraded slightly. If you're shooting surplus, cracked/bulged cases isn't a huge deal. If you're firing factory Wolf, Brown Bear, etc. and it's doing it: I'd stop firing immediately and seek a qualified smithy to check it out. The Finn Mosins are usually pretty well made and won't do this with factory ammo.
 
It was Wolf ammunition, with a steel case (I think, it's grey in colour). I will take the cracked round and the rifle to the gunsmith. Thanks!
 
The only cracked case ammo I ever had was Bulg surplus, was some nasty stuff that left the barrel and chamber all black and sooty like I was shooting a black powder rifle. This was out of a M39 and M44 both. I switched to CZ mil-surp ammo and all was fine in the same rifles.

I run into this a lot with eastern block mil-surp ammo.

Just clean the bore with hot soapy water and then clean as normal.

I have never had cracked Norma or Lapua cases in the same rifles, even the Winchester ammo comes out just fine and reloadable.
 
I took the cracked shell to my local gun shop. The gunsmith wasn't there but there were two fairly experienced guys working there and they both thought it was probably just the case. It's the only one that's cracked, and they pointed out that steel cases are more brittle than brass anyway.
 
Yes, it most probably the Military Surplus ammo. Do you know how old it is, and nation of manufacture?

http://7.62x54r.net/MosinID/MosinAmmoID.htm

This article will aid in the identification...

Steel case lacquered ammo can split. Older ammo, which may not have been stored in the best environment can also split...
 
I have an m44 that i love. I'd say i have about 1 out of 10-20 rounds crack. Its usually just at the neck and its no big deal. Its never bothered me and ive never thought anything of it. Its just old brittle brass, that all. :)
 
Thanks for the replies. I must reiterate that this is not surplus ammo - it is modern factory Wolf ammo in steel cases.

I don't really understand the rationale here either to be honest! Why is is OK for surplus ammo cases to crack, but it's dangerous for factory ammo?
 
MR Divil

I dont think the wolf ammo is as well made as the Winchester, Remington or other popular brands.
I have noticed with my Mauser that the cases are not exact, and some of the rims are thicker than others.
I think you just had a weak casing, that ruptured.
 
I was under the impression that a cracked case could be really dangerous - do you guys think it's safe to keep shooting the Wolf ammo?
 
Better safe than sorry. Do get the rifle checked by a gunsmith with Mosin experience.

This said, I think the Wolf ammo is produced in the same factory as Russian Military ammo, and meets the same requirements... It is a thin steel lacquered case. These "stretch" much more poorly than brass cased ammo. When a round is fired, the case is to, more or less, expand to create a seal with the chamber to get the force focused down the barrel. Steel will not expand as much as brass and can split.

Make sure the head spacing is checked on the rifle. IF it is ok, and the bolt meets spec, then it is the ammo. These rifles vary - and may like a certain ammo over others.

For example, my M39 performed not so well with the Czech lacquered steel cased ammo. It performed exceptionally with the Yugo M30 heavy ball ammo. And did well with the copper brushed steel cased Russian Mil Surp. and the brass cased Albanian mil surp.

Try it with a different ammo. If you still get casings that split, this points to a gun issue. If not, then it points to an ammo issue.
 
Steel cased ammo won't stretch as brass does. It is not unusual to have steel cased surplus ammo crack. I have had this happen to me hundreds of times with 8mm and 7.62x54r. What is protecting you is a strong chamber and bolt. No cartridge, no matter what it is made of, is strong enough to withstand a cracked receiver or broken bolt. A gunsmith examining your rifle for any such defects and giving you a clean bill of health should assure you of safety with surplus ammo. A blown primer or casehead will give you a puff of hot gas into your face - shooting glasses are in order.
 
I personally shoot only Mil;-surp, norma or winchester ammo out of any of my Mosins. I have had too many inceidents with wolf and bear ammo to trust it's quality. The only steel cased ammo I have had that cracks regularly is the russian mil-surp.

The reason nobody gets excited about mil-surp cracking is that it is NORMAL, steel just does not stretch well. The reason people get excited about civillian ammo that cracks is it usually has a higher consistancy and standard. Wolf however is the exact same as the euro mil-surp, same loading lines and same process, so wolf and bear and others with steel cases, it is somewhat expected to have cracked cases.

Now if you are having cracked cases with brass cased ammo like norma and winchester, yes, you have something wrong with the gun and should be checked and repaired or a different rifle used since the rilfes are cheaper than gun smithing fee's at this point.
 
OK I took it out again and this time I shot Bulgarian surplus with brass cases. Weird thing is, the very first round was cracked in exactly the same way as the last Wolf round I fired - a lengthwise crack a few mm long on the shoulder of the case.

I fired about a dozen more after that, and each one was intact.

Does the fact that the damaged one was identical the last damaged one mean there must be a problem with the rifle?
 
I'd get it checked. That sounds really strange. Mosin's aren't built in a way that really allowed escaping gasses to go anywhere but blowing the bolt up in your face. If escaping gasses erode the chamber, it'll be bad. If Wolf Ammo is cracking and breaking on you, I'd DEFINITELY get that checked out. But, honestly, by the time the gun is checked out and repaired: you could just buy a new Mosin in many cases.

So, it's up to you, whether you buy a new one or get this one fixed. I've never had a problem with surplus (but the only surplus I've fired is Yugo brass) or new factory. I usually fire Brown Bear and Wolf, myself. And never cracked a single case.
 
Cracked case

I would stop firing cheap ammo if I was worried about it. I have had problems with Sellier&Bellot cracking in other calibers. The brass was too hard around the neck. Sometimes had problems with Lapua also. Old Japanese brass made by the Chinese in the early 50s always cracks. If it is a minor crack it will do nothing. A good sized gap will eventually burn pits into the chamber and give extraction problems, but it will take a long time. As far as checking the headspace, that is probably not going to tell you anything because that round is called off the rim. I would buy better ammo if you are worried about it.
 
Well that's just it Gunplummer, I am trying to figure out if I should be worried about it or not! People are saying things like "it's probably just the case" or "if it's surplus ammo, don't worry, but if it's factory ammo, stop using the rifle" - it doesn't make sense to me. Surely cracking cases are either dangerous, or they're not?
 
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