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case rupture

2K views 23 replies 16 participants last post by  Stalin's Ghost 
#1 ·
i took my 35 dated izzy to the range to day and shot around 30 rounds before i had one rupture.gun has a matching bolt.the one time i did not borrow a guage to check one out and this happens.got some hot gas in the face.i check each cas before and after fireing.this was a new tin i just got from aim dated 1975 russian light ball.i did order a okie field guage tonight.i all ways hs my mausers but had not got around to buying one for the mn. a few split necks is one thing but this one was way bad for me.
 
#3 ·
This cartridge shows a 'fatigue' type split, not a headspace 'separation', I think. I inspect every round of military surplus ammunition I receive and I find a very small number of rounds with splits in the shoulder of the new cartridges and I discard them. Headspace is never, in my opinion, to be overlooked. The investment cost for a field-reject headspace gauge is small compared to the price of a nice MN/variant and worth a lot in terms of confidence and the alternative, of course is a visit with a trusted gun smith. I own field-reject gauges for my LEs and my MNs and I use them at least on initial evaluation of a new-to-me arm. If one doesn't know that headspace is good, one just simply does not know and that may be ok for some of us but what about the friend who wants to 'shoot a few rounds'? Case-head separations due to excessive headspace almost always show a separation of the cartridge base from the upper 70% of the brass body. Still, this poster has apparently not headspaced his rifle and he truly needs to do that. Knowledge is everything in shooting.
 
#5 · (Edited)
Re Okie gauges: don't leave home (for the gun show) without them. I got the complete kit and use the "GO" gauge as well. A fired case will do the job - checking for insufficient headspace - but folks tend to be unappreciative of people chambering anything at a gun show. There was a recent thread about the MN's apparent lack of gas vents. The ejector groove in the bolt head serves as a vent, as well as the loose fit of the bolt head on the bolt connector.
 
#8 ·
I suspect that the rifle has a generous chamber in the body, something that a headspace gauge will not detect.

Steel cases are not nearly as forgiving as brass. As most of us know, a split at the neck or shoulder is not of much concern. A serious rupture like the one pictured is quite another matter.

I have experienced case cracking with certain lots of ammo in certain rifles. I usually relegate the troublesome ammo to shoot in rifles with tighter chambers. We have a large quantity of Polish LB that is prone to cracking. It is excellent and accurate in spite of this shortcoming- we just need to be selective in firing it in the rifles with tighter chambers.

The loose chambered rifles are usually fine with brass cased ammo, milsurp or otherwise.
 
#14 ·
I have to go with head space on this issue. Cases may be weak but head space is usually the problem. Heads are found on the internet all the time. But remember if you had a bad one you could buy another bad one. Check for a newish one or find one from the adds here on the board.. And in the WTT WTS area. I wish I had an extra one so I could sent it to you to try out. Other areas of the bold body could be worn also.
 
#15 ·
It is surplus. It is old. Quality varies from lot to lot and can to can. Copper washed steel casings do tend to split. I have had some lots that cracked. Not the gun, didn't do that with a different batch.
Some of the current Russian surp seems to be much worse than Bulgarian or Romanian or even the old fireball Albanian. Some of the spam cans look like they were buried in someone's back yard for years. It is what it is and you get what you pay for ...
 
#17 ·
I am sticking with my 'bad brass/cartridge' belief. Excessive headspace usually shows up with the cartridge typically separated into two pieces with a fairly clean circumferential break because of the set-back of the base of the cartridge into the excessive headspace. Headspace gauges: The 'no go' gauge, if passed simply says that headspace is sufficient; if failed it indicates insufficient headspace and a shorter bolt head or a barrel adjustment is needed. If the 'go' gauge is passed, it simply says that headspace is sufficient - it does not say that headspace is NOT excessive. The 'field or field reject' gauge reveals whether or not the headspace is 'within acceptable maximum specification(s) or excessive - in which case, the bolt-head needs to be longer or the barrel set back for safe operation. I've often said that the 'name' on the gauge is not important, it is the 'inch dimension' on the gauge which is important. A SAAMI gauge of .074" is the same as a MilSpec gauge of .074"; know the inch dimensions of importance and order by inch dimensions. Been there, done that decades ago = learned the hard way (wasted $).
 
#21 ·
I would wager it is the ammo - If you continue to have problems with it, then use the components for reloading if you are a reloader. I have had problems with Bulgarian ammo. it is annoying when the case splits and you get that puff of gas in the face - I have had this happen a time or two with split cases. Russian surplus ammo is usually better than some of the other sources, but any of the steel cased ammo can do this.

Pahtu.
 
#22 ·
I've only had neck cracks with some Polish light ball and severe sticking with the Polish heavy ball. I will now inspect each round of the cheap Russian light ball (I mean all ammo) before I fill the mag. +++1 on safety glasses...Please NEVER shoot anything without them...even a BB gun...You know you can shoot your eye out! I Seriously, I wear hearing protection too. Years of trap, & skeet have already taken a toll on me.
 
#23 · (Edited)
I just shot 60 rounds of russian surplus thru my m39. Not a hint of any problem, but heres the catch. I only carried 45 rounds when I left the house. I found a paper packet laying in the yard... been laying there a week in the kentucky rain. peeled off the paper, and the cartdriges were in good shape, except corroded badly near the rims, with orange rust stain. Wiped them off, and all shot perfect. Came back in with 5 rounds in my hand. I ran out of stones to make gravel out of. Those comrades make some boss ammo!
 
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