Severely cracked case out of mosin

Boarder700

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Just get back from the range where I shot my new mosin for the first time. After about 15 rounds I noticed that most of the spent cases were split. Picture below is the worst one. Ammo is surplus Bulgarian silver tip from '71 in a spam can. I have not checked the headspace on the gun (probably bad idea I read LenS's warning in the milsurp section). I read on a lot f other forums that milsurp case splitting is normal, but most people specifically mentioned the neck, this seems really excessive. So should I put the gun away until I can get the headspace checked? Anyone else have a split this bad?

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Do the numbers on the bolt match the numbers on the rifle?

The reason I ask is because if they don't it's probably a issue with headspace (bolt may be out of spec).
 

DW357

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Just get back from the range where I shot my new mosin for the first time. After about 15 rounds I noticed that most of the spent cases were split. Picture below is the worst one. Ammo is surplus Bulgarian silver tip from '71 in a spam can. I have not checked the headspace on the gun (probably bad idea I read LenS's warning in the milsurp section). I read on a lot f other forums that milsurp case splitting is normal, but most people specifically mentioned the neck, this seems really excessive. So should I put the gun away until I can get the headspace checked? Anyone else have a split this bad?

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Damn I just got a shipment of Bulgarian silver tips a couple weeks ago, still haven't opened up the cans yet to shoot them. Still shooting the rest of the Russian silver tips I have. I hope I don't run into the same issue. I'm interested to hear from others what might be the issue. Probably just ammo??
 

Boarder700

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Do the numbers on the bolt match the numbers on the rifle?

The reason I ask is because if they don't it's probably a issue with headspace (bolt may be out of spec).

All original numbers match except for the magazine baseplate. That looks like it was replace in the old world as the new number is stamped, no electro pencil.


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Boarder700

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I just tried chambering the ammo again and it is quite a bit harder to close the bolt with a round. Without a round the bolt closes very easily. With a round it requires about 2x the force. I didn't really think anything of it before because everything I read said the bolt is hard to operate.


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kalash

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I've gone through about 300 rounds of early 70s Bulgarian with just one split case:

IMAG0499.jpg


I'd suggest shooting it and seeing if it happens again.
 

xero2099

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I just tried chambering the ammo again and it is quite a bit harder to close the bolt with a round. Without a round the bolt closes very easily. With a round it requires about 2x the force. I didn't really think anything of it before because everything I read said the bolt is hard to operate.


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perhaps suffering form the mosin sticky bolt I would give a good cleaning to everything and see what happenes
 
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Neck splits like that are usually caused by brittle brass. Excessive headspace could cause a case head separation, which is another thing entirely.
 

Boris

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did you check the chamber? I'd check the headspace too and try different ammo. That being said, you'd be fine regardless. In terms of sticky bolt, it should not stick. Check for burrs, may be polish a few surfaces.
 

Boarder700

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The bolt really isn't sticky, it is actually very smooth. It just requires a lot more force to close it when there is a round in it. I was thinking it might be because the headspace is too small. I actually played around with it a bit though and found out that it is just seating the bullet into the breechface. If I open the bolt but not all the way to the extractor and then close it again with the same round it is just as easy to close as with no round.

I am going to get some commercial ammo to try next time I am at the range. I will pair the results.


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One thing to watch for if it.is cracking that much is make sure the case is all there every time you extract a spent round. I had some cases crack on my dads reloads for my .308 and noticed when i took one out part of the neck had broke off and remained in the rifle. That could be disastrous if another round was fired and i hadnt noticed. That whole batch was turned into pulls.
 
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Im in Bridgewater and have headspace guages for the mosin if you want to check. Pm if so and we can check it.
Just get back from the range where I shot my new mosin for the first time. After about 15 rounds I noticed that most of the spent cases were split. Picture below is the worst one. Ammo is surplus Bulgarian silver tip from '71 in a spam can. I have not checked the headspace on the gun (probably bad idea I read LenS's warning in the milsurp section). I read on a lot f other forums that milsurp case splitting is normal, but most people specifically mentioned the neck, this seems really excessive. So should I put the gun away until I can get the headspace checked? Anyone else have a split this bad?

View attachment 90268


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cutlass442

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buy micrometer and measure before and after chambering the round sound like headspace is too tight and i would think the chamber is full of gunk from the blown out cases.
 
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I've had that happen before. I attributed it to the ammo that was dug out from underneath Sergei's porch in Russia and resold to us filthy capitalists.

Mosins have been killing stuff for a long time, under far worse conditions. I say keep shooting it. If not, I know a guy who will take it off your hands.






Make sure to wear your eye protection.
 

RoterTeufel

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Likely hot rounds. Possibly coupled with cold temps. So long as you keep your rifle clean... that's probably it.


Just get back from the range where I shot my new mosin for the first time.
I just tried chambering the ammo again and it is quite a bit harder to close the bolt with a round. Without a round the bolt closes very easily. With a round it requires about 2x the force. I didn't really think anything of it before because everything I read said the bolt is hard to operate.


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did you check the chamber? I'd check the headspace too and try different ammo. That being said, you'd be fine regardless. In terms of sticky bolt, it should not stick. Check for burrs, may be polish a few surfaces.

Definitely try different ammo. How does the primer look? A hot round will expand more than normal & cause the bolt to stick. You clean out the cosmoline?

[video=youtube_share;gfiXFyIbOZw]http://youtu.be/gfiXFyIbOZw?t=9m26s[/video]

ETA: ffw to 9:10 for hot loads...
 
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Boarder700

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Finally got around to shooting some commercial ammo and the brass looked fine after I shot. I will make sure to keep an eye on my spent casings from the milsurp ammo to make sure nothing gets separated and stuck in the barrel. Thanks everyone.


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