7.62x54R Overpressure???

This is a discussion on 7.62x54R Overpressure??? within the Defensive Ammunition & Ballistics forums, part of the Defensive Carry Discussions category; Hi All, I sure could use some help here. I don't know much about overpressure situations. My new-to-me M44 Mosin-Nagant was exhibiting a "sticky bolt" ...

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Thread: 7.62x54R Overpressure???

  1. #1
    Senior Member Array Joshua M. Smith's Avatar
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    7.62x54R Overpressure???

    Hi All,

    I sure could use some help here.

    I don't know much about overpressure situations. My new-to-me M44 Mosin-Nagant was exhibiting a "sticky bolt" while shooting some Russian surplus ammunition from 1986.

    It has no problem shooting heavy ball from Hungary made in 1951. The action is very slick using that stuff and I can reach over and operate the bolt handle with no problem (I'm a lefty). The ammunition is copper washed steel.

    The Russian stuff is light ball. It has a laquered case mouth and primer, and the case is not laquered. It is copper washed steel as well.

    When I first fired it I could hardly get the bolt open. I then came to the internet forums and found that the Mosin-Nagants have "sticky bolt syndrome." I followed the steps to correct this.

    While it helped somewhat, the problem still existed.

    I took a closer look at my spent cases. This is typical of what I found on the Russian stuff.


    At first I thought these were a couple scratches, perhaps manufacturing defects.


    I then noticed that the case is cracked, with light visible through the crack.

    The rifle is OK. It's sturdy, if not purdy :)

    Can someone tell me if this is a sure sign of overpressure? I don't know what else to look for; I've never seen an example of a flattened primer.

    The bands which go around the cases look to be from some sort of annealing process. Looks like other heat treated metal I've seen.

    Also, this ammo blows moisture of some sort back. Is this indicative of anything?

    Overall, what exactly am I looking at gents? Over pressure, or is this typical of Russian stuff?

    Personally, I think hard extraction + random case ruptures = overpressure.

    The case code is "60" at 12:00 and "86" at 6:00 for those who may be wondering. I do not have a lot number.

    Any help is appreciated.

    Thanks,

    Josh <><

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  3. #2
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    Probably not over pressure,the case cracking is typical of a lot of older milsurp ammo. I once got some 8mm that did the same thing, about every 4th or 5th round. The age of the cases and the breakdown of powder causes embrittlement of the brass.

    Also, be advised that the Russians put millions of rounds of their surplus brass on the market and so that people would buy WW2 and later rounds they repackaged them and the date reflects when it was done, so your rounds may not be from "86", they may be 50 year old rounds that were repackaged then.
    I would rather stand against the cannons of the wicked than against the prayers of the righteous.


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    Senior Member Array Joshua M. Smith's Avatar
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    Hotguns,

    Thanks. Some from another board have helped me detemine that these have backed out and flattened primers.

    Also, extraction is difficult. I first attributed this to the laquer on the case mouth but after I cleaned the chamber and bore extremely well there wasn't much of a change.

    My Hungarian yellow tip still works just fine, and this stuff shows some problems.

    I need the ammo to be sure functioning because it could be called upon to be used to kill some critter up to the size of a large feral dog out here in the country.

    Right now I have it loaded with four rounds of the yellow tip heavy ball because I know that will function.

    I think I need to get some Winchester and see how it functions. That will clear it up as to whether something funky is going on with the gun that I've not detected yet. It's hard to diagnose problems with surplus ammo!

    Thanks,

    Josh <><

  5. #4
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    Another thing about surplus ammo...

    Sometimes it shoots HOT. The thing is, vibration or constant movement can cause the grain size to change, in effect grinding the powder down to a much finer sized grain that original. This changes the burn characteristics of the powder, which in most cases raises the pressure. We have no way of knowing where that powder has been or what it was subjected too, it could have been sitting in an underground bunker for the last 70 years or it could have been transported from one end of Russia to the other in the back of a jeep or even a donkey for that matter.

    If you think its too hot, use your best judgment. Its better to be safe than sorry, blowing up a gun sucks, but losing an eye or part of your nose is worse.
    I would rather stand against the cannons of the wicked than against the prayers of the righteous.


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    Senior Member Array Joshua M. Smith's Avatar
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    Thanks.

    Mostly, I need something that's sure-functioning. I may have to just go with the more expensive stuff anyway to get the softpoints I should be using for coyote watch.

    I really, really like this yellow tip stuff though, even if it is corrosive.

    I'm in college again and can't afford bulk. Dangit.

    Thanks,

    Josh <><

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    Senior Member Array Joshua M. Smith's Avatar
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    I don't know what this means, if anything, but I just tried to chamber a spent Russkie shell and the thing won't go in. It looks like it has a slight bulge about 1/8" up from the rim. This is what is sticking.

    The surplus yellow tip empties chamber just fine.

    Does this mean anything?

    Thanks,

    Josh <><

  8. #7
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    That bulge could be weakened brass or it could be overpressure.
    I would rather stand against the cannons of the wicked than against the prayers of the righteous.


    AR. CHL Instr. 07/02 FFL
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    I agree with Hotguns,

    It could be overpressure or just old milsup. I know that doesn't help but I would not buy any more of the Russian milsup you got. See if you can find S&B or Hotshot 7.62x54R locally for Coyote duty.
    “You can sway a thousand men by appealing to their prejudices quicker than you can convince one man by logic.”

    ― Robert A. Heinlein,

  10. #9
    Distinguished Member Array randytulsa2's Avatar
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    This is only one of the many Mosin adventures that lie ahead. Frustrating to some, but enormously enjoyable to others (like me). Variety is the spice of life! (but be careful)
    "...bad decisions that turn out well often make heroes."


    Gary D. Mitchell, A Sniper's Journey: The Truth About the Man and the Rifle, P. 103, NAL Caliber books, 2006, 1st Ed.

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    Senior Member Array Joshua M. Smith's Avatar
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    Thanks All,

    So far as I know zinc is not involved. The cases are advertised as copper washed steel with red laquer sealant.

    I do not have the pic of the SPAM can it came out of... but I do have some other pics for ya'll:


    Head-on primer view, comparison fired and unfired.


    I'm attempting to show the primer depth here. I don't know if this is normal.


    Case length comparisons.

    Is it just me or does the OAL of the Russian stuff look to be shorter than the Hungarian heavy ball? Photos don't do it justice; the unfired Russian case is definitely shorter in length to the shoulder and to the mouth.


    Circled is the bulge which will not let me chamber one of these spent shells.

    The bulge is present on every fired case I've examined, and is the reason it's not extracting properly. The laquer has very little to do with it and there can't be any cosmoline left in the chamber anyway, after the cleaning I gave it over the course of two days. Remember, this involved a 20 gauge brush and drill as was recommended.

    I was told that the burn rate can change over the years. The ammo is moved around and while it may start out as granules or flakes, the continuous movement gradually makes it finer. Does this make sense?

    Any more comments? It's only doing this with the Russian light ball.

    Thanks,

    Josh <><

  12. #11
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    Want to see a real case failure? I shoot most of my 54R thru M38 and the bolt is always on stiff side, so is the 91/30 too actually and usually it is opening that is hardest.

    This was the worst I had but have had others. I get the impression that dimensionally the ammo is very variable according to source. I have noticed slight cratering on primer pin indent but this seems consistent. It is quite 'hot' ammo usually.

    Case stamp shows 183 one side and 45 other.

    bxn and 98 are however stamped on the more recent batch of Czeck stuff I got a good deal on .. SPAM cans of 800 rounds.

    This case shown is an old steel one and shows what seems to be excessive hardness - if the material was more ductile like good brass I doubt this could occur. Hot Guns makes good observations.


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    Holy Cow P95, I bet that made you a bit anxious about shooting the rest of the batch of ammo that came out of.

    As far as Josh's problem, I would think that the differences in the case's would be the factor in the sticking. Looks like there are slight pressure issues, but more than likely not the true root of the problem.

    Anyway some interesting pictures from both of you.
    Just remember that shot placement is much more important with what you carry than how big a bang you get with each trigger pull.
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    Holy Cow P-95...

    The shell casing reminds me of Highway 7 going though the Ozark Mountains...

    I would have put that one on the shelf just for a reminder...
    I would rather stand against the cannons of the wicked than against the prayers of the righteous.


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    I would have put that one on the shelf just for a reminder...
    It sits close to my puter in fact - not one I was gonna pitch.

    I think it was somewhat of a freak example as others from the old batch have only had the odd small crack near bottleneck area.
    Chris - P95
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    "To own a gun and assume that you are armed
    is like owning a piano and assuming that you are a musician!."


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    Just a note there is a lot of varibility in East Bloc ammo. If you can find a lot number there is (Link Not what I thought but what I have.) a list with shooters reviews.

    It might be helpful.

    A side note: I was at a Microbiology conference and got to met some Russian Diease Control experts. I remeber them describing the work mentality during the Soviet era as "They pretend to pay us and we pretend to work." This might explain some of the quality conttrol issure in east Bloc surp ammo.
    “You can sway a thousand men by appealing to their prejudices quicker than you can convince one man by logic.”

    ― Robert A. Heinlein,

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