Interesting mystery... blown up S&W 317

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  • Doctor_M

    Certified Mad Scientist
    MDS Supporter
    This is not my gun, nor do I know the person who wrote this, but I read the account this morning and am scratching my head.

    Summary,

    Guy shoots a 317 that has been in storage for a long while. Shoots the old/stored ammo and has some duds (some of which go off on the second strike). Loads junk ammo from the 60s he had lying around (Tru-Test). Bang, Bang, BOOOMMM. He is trying to figure out what happened. At first blush, it looks like an over charged factory round (base of the cartridge blew out towards the breech face).

    He suffered some minor cuts and ouches but nothing he won't recover from. Gun shows some damage, but still is "functional", although I'm not sure I would ever put another round through it.

    Part of the mystery is the fired round next to the one that blew looks like a soda can that was crushed under pressure. Result of the blast or part of the symptomology?

    Article and detailed pictures are here:
    https://www.activeresponsetraining.net/why-did-my-gun-blow-up

    I'm curious. I don't think I've ever seen anything like this.

    Good place for PSA... wear eye protection... always.

    What does the brain-trust think about this?
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,733
    Socialist State of Maryland
    He needs to run a tight cleaning rod through the barrel. I'm betting one of the "dud" rounds was a squib and he had bullet stuck in the bore and touched off another one. Maybe he even had two stuck bullets. I have had barrels with five rounds in them brought to me for repair.

    I have shot many, many rounds our of my 317, some from the seventies. The older federals would have burn throughs as the brass was brittle from age but you never notice that when you are shooting. The only thing that will cause a blow out that sever is it something was keeping the gas from going forward.

    As for the case next to it, I think the peeled back brass channeled the gas into the next chamber and that crushed the case.
     

    Doctor_M

    Certified Mad Scientist
    MDS Supporter
    He needs to run a tight cleaning rod through the barrel. I'm betting one of the "dud" rounds was a squib and he had bullet stuck in the bore and touched off another one. Maybe he even had two stuck bullets. I have had barrels with five rounds in them brought to me for repair.

    I have shot many, many rounds our of my 317, some from the seventies. The older federals would have burn throughs as the brass was brittle from age but you never notice that when you are shooting. The only thing that will cause a blow out that sever is it something was keeping the gas from going forward.

    As for the case next to it, I think the peeled back brass channeled the gas into the next chamber and that crushed the case.

    That could be it... it is funky looking, that's for sure.
     

    Magnumite

    Ultimate Member
    Dec 17, 2007
    6,564
    Harford County, Maryland
    The collapsed fired case next to the ruptured case was probably from combustion gas from the ruptured case blowing between the case and chamber wall. Forst time I’ve seen a rimfire case blowout.
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,733
    Socialist State of Maryland
    The collapsed fired case next to the ruptured case was probably from combustion gas from the ruptured case blowing between the case and chamber wall. Forst time I’ve seen a rimfire case blowout.


    Rimfire cases are made from a different brass than centerfire cases. As they age, they get brittle. Keep them long enough and you will see them split, usually at the firing pin indentation.
     

    Art3

    Eqinsu Ocha
    MDS Supporter
    Jan 30, 2015
    13,267
    Harford County
    This photo intrigues me:
    IMG_1696-rotated.jpg


    I don't think I've ever noticed the "ghost" impressions of the rounds on any of my revolvers...not that I've really looked for them (I will now)...just seems odd.

    As to his problem, the missing metal around the insert that makes the breech (there's probably a proper name for it...the "firing pin donut") seems like it makes a huge cavity that an expanding (perhaps brittle and overcharged) casing would try to expand into...and it seems to line up exactly where it blew out. I find it hard to believe that all that boogering up around the firing pin donut happened just from this one round. I wonder if it hand been changed, and those are apprentice marks from the removal of the old one?

    Also, look at the face of the (proper name again unknown) pin that releases the cylinder. It looks like it has very fresh (and very coarse) machining marks on it...and maybe even a bur?

    That gun appears to have a lot of "history." In this pic, he claims the dirtiness is powder residue from the kaboom...but look in front of the cylinder release on the frame. That looks much more like actual dirt (like the stuff Mother Nature makes and hides under grass) than burned powder residue to me:innocent0
    IMG_1693-rotated.jpg


    I have two additional theories trying to formulate in my noodle...both accepting contributing factors of potentially old brittle brass: 1) That well worn and worked on revolver was slightly out of time. The bullet wasn't 100% lined up and had to be pushed harder through the forcing cone resulting in more backpressure. 2) Crud or dirt made the chamber tight, making higher pressure.

    Dunno :shrug: Hope it doesn't happen to me :innocent0
     

    John from MD

    American Patriot
    MDS Supporter
    May 12, 2005
    22,733
    Socialist State of Maryland
    This photo intrigues me:
    IMG_1696-rotated.jpg


    I don't think I've ever noticed the "ghost" impressions of the rounds on any of my revolvers...not that I've really looked for them (I will now)...just seems odd.

    As to his problem, the missing metal around the insert that makes the breech (there's probably a proper name for it...the "firing pin donut") seems like it makes a huge cavity that an expanding (perhaps brittle and overcharged) casing would try to expand into...and it seems to line up exactly where it blew out. I find it hard to believe that all that boogering up around the firing pin donut happened just from this one round. I wonder if it hand been changed, and those are apprentice marks from the removal of the old one?

    Also, look at the face of the (proper name again unknown) pin that releases the cylinder. It looks like it has very fresh (and very coarse) machining marks on it...and maybe even a bur?

    That gun appears to have a lot of "history." In this pic, he claims the dirtiness is powder residue from the kaboom...but look in front of the cylinder release on the frame. That looks much more like actual dirt (like the stuff Mother Nature makes and hides under grass) than burned powder residue to me:innocent0
    IMG_1693-rotated.jpg


    I have two additional theories trying to formulate in my noodle...both accepting contributing factors of potentially old brittle brass: 1) That well worn and worked on revolver was slightly out of time. The bullet wasn't 100% lined up and had to be pushed harder through the forcing cone resulting in more backpressure. 2) Crud or dirt made the chamber tight, making higher pressure.

    Dunno :shrug: Hope it doesn't happen to me :innocent0


    I'd say he was shooting many brittle cases and the gas burned the breach face. As for "ghost" head marks, many revolvers make them. Some are more noticeable than others.

    I don't see any lead build up where the barrel and frame meet. If it is out of time, it spits lead and you get a build up in that area.

    One thing for sure, someone really abused that gun. :sad20:
     

    Art3

    Eqinsu Ocha
    MDS Supporter
    Jan 30, 2015
    13,267
    Harford County
    I'd say he was shooting many brittle cases and the gas burned the breach face. As for "ghost" head marks, many revolvers make them. Some are more noticeable than others.

    I don't see any lead build up where the barrel and frame meet. If it is out of time, it spits lead and you get a build up in that area.

    One thing for sure, someone really abused that gun. :sad20:

    I understand why there would be the ghost head marks on the actual breech from the rounds going off, but I'm having a hard time understanding what makes them at the other locations. I just looked at the revolvers I have handy. Most have the expected mark at the firing location (although a few do not at all). The two that I know I have put the most rounds through are, ironically, both .22's. If the firing position is 12:00, the both have additional marks on either side of it (roughly 11:00 and 1:00). I never noticed that before...weird. The one that I would assume to have the highest round count is a Colt 1917, but it shows almost no marks at all. I wonder if the moon clips prevented it, or it just hasn't been shot as much as I expected over the last 100 years :shrug:

    I definitely agree about the abuse. Normal wear and tear is one thing...but dirt and gouges are another. I'd love to have it in my hands to look for other clues...and scratch at the gouges with my fingernail and sigh.:sad20:
     

    Magnumite

    Ultimate Member
    Dec 17, 2007
    6,564
    Harford County, Maryland
    If you are considering buying a particular used magnum revolver look at the frame breech face. If you see little pit marks that is frame etching (erosion). You see it on the forcing cone and barrel breech face, too. Loose primer pockets and high end loads lead to the erosion. Seeing that you have more info to consider how much you would be wiling to pay.
     

    Doco Overboard

    Ultimate Member
    I notice that the ruptured case is at the bottom of the rim and not at the top where the firing pin indent is. Thats where the powder is laying.
    My guess is that a glob of priming propellant was left inside some of that ammo and because the powder for a 22 is progressively burning the cartridges just exceeded mean average pressure for a 22.
    Also by all the hammer marks and fouling on the recoil shield I would also say that was not the first time it happened in that revolver.
    22 ammo is not easy to manufacture because it was originally designed for black powder and now loaded with some sort of smokeless that needs to not overcome the manufacturing design of the case and yet deliver consistent performance for accuracy and function of a multitude of different firearm designs.
    Theirs not a lot of room for a mistake during manufacturing.
    Thats just my take and a guess based on the available information.
     

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