case swelling, primer flush, danger?

Discussion in 'Mosin Nagant' started by potbellyFin, Aug 18, 2010.

  1. potbellyFin

    potbellyFin G&G Regular

    I fired some brown bear 203 grain soft point today in my m39. I looked at the fired case(five total) and could barely see a slight increase in case size about a quarter of an inch above the rim. Also, the primer is flush with bottom after firring.. Is this a sign of a serious problem or normal?
     
  2. waterdog

    waterdog G&G Enthusiast

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    Is it a M38? did you have the headspace checked?
     

  3. Not sure about the primer, but noticable change in SHAPE of the fired cartridge case always means that chamber is out of spec - typically, due to the wear or erosion or somebody messing it up... Difficult to say if it is dangerous or not. I have one rifle which fireforms empties with a slight bulge right in the case neck area, shoots allright and I'm not really concerned about safety, but it does look somewhat undesirable.
     
  4. I think if it were me I'd make a cast of the chamber, then do a lot of measuring, and check the headspace to be on the safe side of things.
     
  5. 338RUM

    338RUM G&G Evangelist

    I have to second mouser868 on this one, better safe than going through life with missing fingers!
     
  6. SwedeSteve

    SwedeSteve Freedom Zealot Forum Contributor

    Headspace it. Is it hard to close the bolt or open it ??
     
  7. Mooseman684

    Mooseman684 G&G Newbie

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    Headspace is only at the rim with Mosins...The chamber can be worn and it will headspace just fine...
     
  8. potbellyFin

    potbellyFin G&G Regular


    No ti closes easly and is not hard to eject.
     
  9. SwedeSteve

    SwedeSteve Freedom Zealot Forum Contributor

  10. gandog56

    gandog56 G&G Evangelist

    This is an example of flattened primers. Were your's this bad?

    [​IMG]
     
  11. samuel

    samuel G&G Newbie

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    Many,many old war weapons had waaaay oversize chambers.We had a discusion on here about that very thing and I claimed the rifle couldn't be fired safely and someone else said he was doing it by neck resizing only.I researched it and with low pressure loads they do it even when the chamber is like .020" (and under) oversize.What MM was talking about is the chamber can well be .020" longer than the case or several .000" bigger in diammeter and checking headspace would "NOT" show it. This explains the situation better than Dumb ol' me can. ,,,Surplusrifle.com - Measuring Headspace ,,,sam.
     
  12. Sober

    Sober G&G Newbie

    My primers looked almost like that after I fired my Mosin is this bad?They don't look so stretched out though I mean you can still see the gap around the primer in between the case and primer but the primer definetly doesn't sit as deep as a non fired round and there is no swell in the case either. If there is swell its so minor that I cant tell the difference . Reason I ask is cause a buddy Test fired my mosin today cause I went to a bbq way out in the sticks and brought my mosin .I was nervous about it cause ive never fired something this powerfull before so he just grabbed my rifle and said **** it and popped off a round at a tree stump in the woods and gave me back the Rifle and said yup it works but he didn't want me to shoot anymore cause it would p-off the nieghbors cause its so loud so I didn't get a chance to shoot it.... I'm taking it to the range next weekend cause that was a bad teaser but at least I know it fires now.
     
    Last edited: Aug 22, 2010
  13. potbellyFin

    potbellyFin G&G Regular


    No sir not like those. More, Like these in post twenty. But the bulges are not this bad. 7.62x54R Overpressure? - TheHighRoad.US


    I fired some more rounds out of the same box(Brown Bear 203 gr sp) in my '43 m38 and the spent cases looked the same. Maybe this is normal? or not?
     
    Last edited: Aug 22, 2010
  14. Dennis

    Dennis G&G Evangelist

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    I would suppose that the cases are looking like they do because you are fireing a heavier bullet that the regular 147 to 167 grain projectiles that the Mosins are designed for. If the 203 grain bullets are accurate then shoot em. haveing some common indications of increased pressure on the cases is not unusual nor should it be unexpected. If this was older ammunition I would be concerned about case head rupture, yet over all these years I have only seen one casehead rupture in a mosin and that was a type 53 that looked like a fence post. keep an Eye on your cases and GO SHOOT THAT GUN!!!
    if you do have a case head rupture the only thing I have ever seen it do was blow open the bottom of the magazine and spit brass and gass out the bottom. the extractor stayed intact... It wasnt that bad of a catastrophy. If you had your eyeball or hand in the wrong place it might have been bad. allways wear safety glasses and hold the rifle correctly
     
  15. not sure why you're linking us to pics of someone elses spent cases, but since you did, read post #24. makes more sense to me than the rest of the posts on that page.
    you're primers sound fine (without seeing them) and your cases sound fine too (without being able to measure them to see if they're about to seperate).
    the chambers in mosins are not very consistent. all my wartime mosins stretch the brass (and steel) farther than my pre-war rifles. the finns have the tightest chambers. when i reload, i have to keep all the empties with the rifle they came out of in order to be able to use them without full length resizing. i haven't measured the difference between the rifles. i've never had a head seperation even after reloading the brass eight times. to see a slight bulge in them doesn't worry me much. if it really bugged me, i'd take some cases to someone with accurate equipment and measure the case wall thickness top to bottom to see if it was about to seperate.