Ruptured Brass Cases...BAD for my Mosin Nagant???

[Southern Shooter]

I put about 80 rounds through my Mosin Nagant M-44 over the last two weekends. I am using 1952 147 grain Bulgarian 7.62x54R brass cased surplus ammunition that were sealed in tins. Accuracy has been acceptable. But, I have about 6 split cases out of the 80 rounds. They have split about midway down the case and of course showed burn marks I guess where the hot gases escaped.

OPINIONS Please...is this bad for my gun? Is this too many ruptured cases to have in 80 rounds of surplus? By the way, when I opened the tins I found a couple of the cases were cracked and the bullets had fallen out. Maybe it happened during the actual manufacturing??

Thanks

 

[MikeJackmin]

Yes, it's bad. You can get a faceful of hot brass and ruin the rifle if it lets go a little further down towards the base of the case. Remember, the bolt does not hold the high-pressure gasses in! It justs supports the case in position, so that it can hold back the gasses. Stop shooting this stuff now.

I'd suggests finding some good quality commercial ammo, or at least some good surplus ammo which has functioned well in another rifle without splitting. If the problem goes away, then it's just this batch of ammo, and you should dispose of it. If the problem continues, you may have an oversize chamber and you can probably replace the whole rifle for less that the cost of a repair.

 

[Slamfire]

Case neck splits from workhardened brass will not damage your chamber. Not really. However as stated if the crack goes through the case head, you will have a big problem.

You ammunition is new and has problems. The case necks are splitting. That could be due to poorly annealed case necks. Brass workhardens. Case necks are the most workhardened section of a case. Look at new US military ammunition and you will see a color change just around the shoulder. I like to see that and it is the colors that come from proper case neck annealing. Commerical suppliers polish those colors off because customers like shiney ammo.

The powder in the cases could be deteriorating. I have loaded ammunition with surplus powder, found a year later an abnormal number of cracked case necks. When I pulled the bullets I found green corrosion on the bullet bases. The powder must have been outgassing (something) and causing the brass to season crack. That may also be your problem.

Either way, what you have is at the end of its shelf life.

I would not trust my face behind the stuff.

 

[GD]

Split cases after firing is very common in 7.62x54 ammo. I, and many other shooters have experienced hundreds of split rounds. If you are relying on a thin brass or steel case to protect you in a chamber then I have a surprise for you. I agree that if the splits are going down to the case head, then you probably have a chamber or headspace problem and should have it checked. I always wear glasses when I shoot because I don't want to risk my eyesight. I have never had hot gases come back to me from the hundreds of split cases I have experienced. Only twice have I experienced hot gases and both were due to punctured primers and neither caused any discomfort. I would not hesitate to shoot Bulgarian ammo that is experiencing what you described. Of course, do not fire any ammo that has existing splits or other damage to the case. You are going to find that even brand new production ammo is going to split in your Mosin.

 

[mainmech48]

Not to try and put a t--- in the punchbowl, but IMO you should investigate the distinct possibility that there's something else going on here besides the ammo. IIWY, I'd have a competent professional gunsmith slug the bore and make a chamber cast to check for out-of-spec/worn dimensions. I'd also have him look at the headspace, just to see where you are, as it were.

Personally, I would be antsy about putting my own boyishly-handsome face, not to mention my irreplacable eyes, in close proximity with any ammo until I did know exactly what's what. YMMV, but there ain't no do-overs if things go wrong. Guess it boils down to how you feel about your luck on any given day.

 

[Dionysusigma]

SlamFire1: The case necks are splitting. That could be due to poorly annealed case necks. Brass workhardens. Case necks are the most workhardened section of a case. Look at new US military ammunition and you will see a color change just around the shoulder. I like to see that and it is the colors that come from proper case neck annealing. Commerical suppliers polish those colors off because customers like shiney ammo.

Wow--never knew that. I always thought the discoloration was because it had been linked, and oil from the links got on the case... *shrug* Ya learn something new every day.

 

[Taurus 617 CCW]

As with what all the other guys have said previosly, I would not shoot ammo with split necks. I bought some surplus 8mm ammunition a couple of years ago for my Turkish Mauser and found about 20% of it to have splits in the neck. THIS IS BAD STUFF!!! I'm not saying that it's bad to shoot surplus ammo, I am just saying that it's good to give it a decent inspection first. It's no walk in the park to have hot gasses or a bolt come flying back in your face. This kind of thing can kill you! Take it to a gunsmith and have them check it for headspace. At the least you can be at ease knowing that your firearm is safe to shoot. Your life is not worth gambling with.

 

[nobody_special]

If I may resurrect an old thread...

I had the exact same problem today; fired 25 rounds of Bulgarian heavy ball through my recently purchased M39, and 7 had splits along the side.

These are not split necks, and all but one of the splits are well away from the case head. All the cracks are all longitudinal, so case head separation may not be a danger (?). Also, the ammunition was not split or cracked before firing. I checked my rifle's headspace with a self-made field gauge and it's fine.

I also see some "cratering" of the primers.

I'm not sure if this is a safety hazard or not... Unfortunately I have quite a bit of the Bulgarian heavy ball.

(I dented the necks of some cases in order to make them easier to identify later.)

 

[sigma 40ve]

IMO your problem is ammo related, and I would not use any more of the ammo in question. Here is why and my experience--

Just got an opened can of 300 rds Bulgy 147 gr yesterday for $30. There were about 12 rds loose, the rest still wrapped in paper. When I got it home and inspected it, about half of the cases showed corrosion on the body or around the primer. 5 to 6 of them had even split or corroded thru from the inside at the neck and the bullet was out or almost out. I got them from a BIG dealer, I called and they did offer to exchange for other. I am debating whether to exchange it or just pull the bullets for reloading. If I am reading other bad issues about Bulgy, after seeing what I bought yesterday, I don't think I want any more. Seems as if the powder is starting to go bad in this ammo, mine was dated 51.

 

[fletcher]

Mosins can be picky about surplus. If you have a friend with one, trade some ammo and see what happens. If the cases were splitting once in a while, and not that badly (more like cracking) I wouldn't worry about it.

 

[Ol` Joe]

IMO your problem is ammo related, and I would not use any more of the ammo in question. Here is why and my experience

I agree with the posters cautioning against useing any more of this ammo. The purpose of the case is to seal the gases and keep them in the barrel, not in an unprotected chamber. The case is a gasket and if it ruptures it is failing. I`d not want to be shooting a rifle that I never knew where the next failure would occure. The gas escaping from the case is also eroding the chamber walls where ever it contacts, just as it erodes the throat of your rifle when fired. This can, over time, cause a rough chamber and feed/extraction problems.
I suspect there is corrosion of some type going on with the cases where it isn`t readily appearent. The brass is weakening and at some point it is losing its ductility and cracking instead of stretching. Work hardening is cause from expanding and resizeing the brass back to spec, the same occures when bending a wire until it breaks. I have seen it in case necks (its most common here) where the neck expands to release the bullet, is sized back smaller then needed to insure it doesn`t "spring" back and cause loose bullet tension then expanded back up before loading to place the ID of the neck to a proper size to accept the bullet with out collapsing or scraping the bullet.
The fact this is new ammo and cracking on the body walls makes me believe the cause is something other. JMHO......

 

[nobody_special]

I just pulled apart one cartridge. The powder is stick-type and looks fine, with no strong smell. The bullet is 150 gr. hollow-based, so I was mistaken -- this is light ball, not heavy ball. The brass shows no signs of corrosion from the outside. I think it's okay on the inside too, but it's hard to tell. The paperclip test shows some roughness on the inside, but looking with a flashlight, I don't see anything. I'll fire the primed case and then cut it in half with a dremel.

This can't be the result of work-hardening, as the cases are unfired and the splits aren't at the neck. Maybe a bad batch of brass...

Can this type of failure case catastrophic damage in a Mosin-Nagant? I was really worried at first, then I realized that unlike a semi-auto, there's no risk of firing out-of-battery... at least the bolt is always locked. Don't get me wrong, hot gas and bits of brass are bad enough...

 

[Threejs]

When I got a can of the bulgarian light ball, I disposed of 25% of he because of deep crimps in the case or cases that were cracked or had "seams' running the length of them. Of the ones I have kept and fired, I have had 1 split so far and it was around the neck.

In the picture above, the only round that would have bothered me is the 3rd from the right. It is close to the rim , and show signs of having leaked around the rim. On 7.62x54r the case seals at the rim, not like mausers or other rounds that seal at the shoulder. If you look at the other rounds, there is no discoloration, that would suggets a problem, and you can see the color difference where it sealed against the chamber wall.

Splits in the neck area are common. Splits at the shoulder usually get my attention, but when it starts to get near the rim I worry a little.