7.62x54R steel case splitting problem


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dm1333
February 4, 2006, 12:38 AM
I took my M38 out today and fired some surplus (Polish?) ammo while sighting in my scope. Several of the rounds split the case lenghtwise from just under the shoulder to just above. The rounds were not hard to eject and I have not had this problem with Wolf, Brown Bear or Winchester Metrics. Has anyone run into this before? The gun shows no signs of headspace problems, leading me to wonder if anyone has run into this problem with Polish ammo. The rounds were 180 grain copper washed. On the bright side my groups are down to the 1.5 to 2 inch range at 65 yards and I still need to do more trigger work. Anyone know where I can pick up a digital caliper? Mine is broken so I have not been able to take my sear down to .395 to really lighten the trigger pull. Right now it is still heavy but smooth.

Don

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Sleeping Dog
February 4, 2006, 12:47 AM
I've run into the same thing with russian ammo. The splits don't seem to cause any problems. I don't reload that caliber, and I don't reload berdan primed cases, so I don't pay any attention to the splits. All the "brass" gets tossed out.

Regards.

P95Carry
February 4, 2006, 12:57 AM
Seems some misurp is real ancient - and the steel stuff far from robust!

This was a case from a shoot not too long ago - after going thru another guy's Mosin - it fired Ok but the case sure was a mess! ;) Some others were similar now and again but not as bad. Ammo was a can of mixed ''who-knows-what''!


http://www.acbsystems.com/boards/thr/shoot7/762x54r-fail-379-s.jpg

jeremywills
February 4, 2006, 12:59 AM
Have not had that problem yet. Everything I have used was steel cased, modern and surplus.

I would like to know what causes it too.

P95Carry
February 4, 2006, 01:04 AM
I have tried to theorize on cause - pure speculation but - I have the feeling that steel this lacking in ductility must have been maybe too high a carbon material - also I think wall thickness is very lacking and so weak by default.

Furthermore looking at some areas - there is almost the impression of some type of corrosion from within - no idea what propellant goes into that old stuff!

Oh and last of all - if case undersized on tolerance and chamber of gun in use oversize (relatively) - then more likely there will be ''overstretch".

I think if we use the real old stuff this will occur now and again - maybe random - or perhaps attributable to one source. The headstamp on that pic of mine tells very little - tho suggests it was 1945 vintage!!!:eek:

dm1333
February 4, 2006, 01:06 AM
Thanks guys. I didn't really think it was a problem but it's good to hear other people have seen it. Except for a new synthetic stock and the sear work my pig killer is ready:)

jeremywills
February 4, 2006, 01:34 AM
all of the surplus ammo I have used so far came fresh out of a sealed tin can, it looked super clean, so maybe once its been exposed for long periods of time maybe the corrosive stuff inside has done its magic on the casing????

just thinking out aloud here, I could be wrong on that, but it seems logical, if that salt in the powder will chew up a bore, why not the casing its been residing in for the past 60 something years

dm1333
February 4, 2006, 01:45 AM
I figured it was that steel cases are less malleable than brass and would be more prone to splitting.

jeremywills
February 4, 2006, 02:01 AM
I dunno sir, its just a theroy I had. I dont know ???? really, honestly though it makes sense to me.

If its been sealed in a tin for all these years, its not been exposed to the elements etc.... if its been out of that tin for a long time could temperature and what not have caused the internals to turn to rust possibly?

Actually this would be interesting to know if thats possible or not, like I said more an FYI thing and Im learning too here, hoping someone comes along and sheds light on it.

Sunray
February 4, 2006, 02:38 AM
"...while sighting in my scope..." If you're not intending to use that ammo for hunting or whatever, you'll have to sight in again no matter what kind of poor ammo it is. Sight in at 100, not 65.

dm1333
February 4, 2006, 02:59 AM
The ballistics of that load and the Winchester Metrics seem to be the same. I sighted in high at 65 yards and if my calculations are correct I should be 1 inch high at 100 yards. That will allow for some longer range shots but most of the shooting around here is in thick brush and closer ranges. I haven't checked the zero yet with the Winchesters but tomorrow I am heading to Big 5 to pick up some more Winchester. Your point is well taken though. Thanks.

Don

rockstar.esq
February 4, 2006, 03:16 AM
just thinking out aloud here, I could be wrong on that, but it seems logical, if that salt in the powder will chew up a bore, why not the casing its been residing in for the past 60 something years

Corrosive ammo is a product of corrosive primers not powder. The seal on the ammo can is probably not airtight as this would play havoc with air freighted ammo cans. Those of us living in Colorado now all about how cans get inflated when they are sealed at lower elevations. I would tend to think this has tons more to do with steel cases made to be disposable.

Onmilo
February 4, 2006, 04:33 PM
Just my two cents here.
My personal observation of many of the current "Arsenal Refinished" carbines that have shown up the last few years is that they weren't arsenal refinished at all.
They were refinished by a commercial source and many of the chambers and bores appear to be polished and recut which results in larger than original dimensions and consequently, split cases when the guns are fired.
Since these guns come from ex-communist countries desperate for hard currency and lacking a proof standard it is luck of the draw, literally, as to what you might receive.
Caveat Emptor.

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