ammo - cracked case?


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random_gun
February 24, 2013, 07:42 PM
Today I noticed cracked cases when I was inspecting fired rounds.. New ammo (at least that's what I think..)

7.62x39 Berdan-primed, non-reloadable, non-corrosive, Russian-production rounds in lacquered steel casings (http://www.sportsmansguide.com/net/cb/500-rounds-762x39-123-grain-fmj-ammo.aspx?a=981928)

7.62x54 non-reloadable, corrosive, copper-washed cases (http://www.sportsmansguide.com/net/cb/440-rounds-762x54r-147-grain-fmj-ammo.aspx?a=865012)

Is this normal? I am a bit concerned if the case cracks too early and makes a powder splash

The crack on 7.62x54 is more like scratch when the round was chambered, the bolt is a bit hard to close sometimes... by hard I mean i can't close it with one hand while the other hand is holding it... I can manage to close it while it's setting on the rest.. Should I just push harder or check something? I just got the m91/30, wiped the bolt and barrel with hoppers and took it to the range. I noticed if I close the bolt fast(push it all the way down) it's not too hard to close. But if I push it forward, take a look then try to close it.... it's gonna be hard
I checked firing pin protrusion and it was good


the 7.62x39 is fired from an ak47. I never noticed cracked case before. I have always been using brass(Tula/Herters, Brown Bear). These lacquered steel cased ammo make some special smell when fired... kinda plastic smell

Thanks

http://i.imgur.com/1wDvydhl.jpg

http://i.imgur.com/1unB5fTl.jpg

http://i.imgur.com/v1t4ytUl.jpg

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Mccarty
February 24, 2013, 08:17 PM
you start the post by stating that both rounds are non-reloadable.

You mention the crack was more like a scratch when chambered and the bolt is hard to close. Are you saying you are inserting reloaded or new rounds that are already cracked? or are you trying to rechamber an already fired and cracked round?

firesky101
February 25, 2013, 12:05 AM
Hard to tell from the tiny pics on my phone, but looks like you might have a headspace issue on the 54r. As for the 39 not sure, is this a new problem? Could be an excessively loose chamber.

Hardtarget
February 25, 2013, 12:12 AM
I've seen one case like that from my .303. Not something I want to see often.

Mark

No4Mk1*
February 25, 2013, 05:15 AM
It looks like the 7.62x54r shoulders are not cracked but creased. I have had some do that and i think some had a crease even before firing. Never experienced any problem from it.

briansmithwins
February 25, 2013, 11:09 AM
Looks like two problems: I'd get the headspaced checked on the 7.62x54R rifle ASAP.

Cracked/split necks are usually a cartridge manufacturing problem.

What are the headstamps on the cartridges?

BSW

ldlfh7
February 25, 2013, 12:48 PM
+1 for headspace on the 91/30. I have shot thousands of the same rounds out of my 91/30's with no issues.

ldlfh7
February 25, 2013, 12:50 PM
Also -

May try a serious cleaning. There could be cosmoline all over the place making the bolt tough to use but that would not explain the cracked cases. Just my 2 cents

stubbicatt
February 25, 2013, 12:55 PM
In the second photo, where the two x39 cartridges are depicted, the one on the left looks like it was an OBD, as the shoulder junction on the neck of that case is such that the headspace looks excessive to me. It may not be that at all, as the lighting in the photo could be deceiving me.

It would be worth it to have someone verify the headspace on both rifles.

I have never had a Mosin Nagant in which the bolt was hard to close. Since these headspace on the rim, most of them I have experience with have had pretty long chambers, noticeably so, and I have not witnessed such splits or burn-throughs like these.

random_gun
February 25, 2013, 06:44 PM
All these rounds are new... I never tried to rechamber a fired round

I didn't notice cracked 39 case before, but I was using different ammo

I just did a through cleaning on the mosin, will take it to the range later this week and see if it corrects the problem..

I guess I can try to chamber a round then unload it to see if the round is damaged during chambering..

Headstamp on 54 is 60 62, on 39 it's 7.62x30 12. Picture uploaded

Robert101
February 25, 2013, 08:11 PM
The deformation on the 7.62x54r case taper is very distorted. It looks to me like an out of spec chamber. The case material is over expanding into the chamber at the taper causing a tear of the case material. I would not shoot that gun any more until the chamber is verified in specification. The bolt not closing seems to contradict the excessively loose chamber theory. The barrel chamber seems seriously messed up.

ball3006
February 25, 2013, 08:22 PM
Are you loading the round in the 91/30 by dropping it right in the chamber or are you loading the round in the mag, then closing the bolt? Chamber of the AK looks out of spec to me.....chris3

random_gun
February 26, 2013, 12:07 PM
I was dropping the rounds directly into the chamber of m91/30.

random_gun
March 9, 2013, 09:23 PM
I cleaned the m91/30 with bore snake and soaked metal parts in warm water with dish liquid.. At the range today it worked fine for first 10 rounds then the bolt got really difficult to close..
I took the bolt out but didn't notice anything wrong.. It can still fire but I need to try really hard several times to close the bolt.

When I push the bolt all the way down (before closing it), should it pick it the round (rim in the extractor)? I noticed if the rim is in the bolt face(I can see it when I pull the bolt back), it closes fine but if not it will be almost impossible to close.
The bolt closes easily without a round.

Ordering a headspace guage... Not sure how much the gauge is going to help since it will likely fail the go gauge test

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