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Thread: Kaboom from high round count?

  1. #1
    Boolit Buddy
    catmandu's Avatar
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    Kaboom from high round count?

    https://www.thefirearmblog.com/blog/...50-000-rounds/

    I saw this short article on the gun blog and it basically states that a rifle that had seen 50k rounds went kaboom and the high round count was the probable cause.
    I guess I never thought of it as being that dangerous. Maybe a bore obstruction from a jacket getting left in the bore.

    What do you think?

    Paul in WNY
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  2. #2
    Boolit Master

    Hickory's Avatar
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    A high round count did not cause that!
    Looks more like a high pressure round caused that!!!
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  3. #3
    Boolit Grand Master






    Lloyd Smale's Avatar
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    that is ALOT of rounds through a bolt action gun. I guess its possible that the metal was fatigued or that there was a flaw in it that took that long to fail. Other thoughts are that if they were that lackidaisile with there loner guns that they didn't clean it either and it was about plugged with copper fouling. I would have to think if that was the case though they would have had sticky brass or even blown primers well before it exploded. Something funky with those pictures too. For one in one picture it has a wood stock and the other its painted black. In one picture it shows the 308 case head still in the gun and the other it shows a case with the head blown off. My guess is its some kind of internet nonsense.
    Soldier of God, sixgun junky, Retired electrical lineman. My office was a 100 feet in the air, closer to God the better

  4. #4
    Boolit Bub
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    The tired throat allowed a primer-only round to lodge a bullet farther down than normal. This is more barrel burst than initial chamber load. For some reason, people laugh off reloads that have no powder, like it's ok, without appreciating the loss of control that it represents.

  5. #5
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    catmandu's Avatar
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    I agree Lloyd,
    I think the pic that shows the case head missing was taken from the front, the black was the split barrel.
    Who knows what did it in, I just though it would be interesting to share and think about.

    Paul in WNY
    Think you can, or think you can't. Either way your right.

  6. #6
    Boolit Master

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    You need pressure to build a pipe bomb - so probably plugged bore .

  7. #7
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    Lloyd Smale - I think I see why you thought the stock was black; In the 3rd picture, the pic is taken from the front and that's the barrel (which is blued) you're seeing, not the stock. That photo shows the mouth of the case, split, understandably.

    That had to be "TOO exciting" for the person who squeezed that trigger. Hope they had spare pants in their vehicle!

  8. #8
    Boolit Master

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    But as the article points out, there are zero pressure signs on the primer or case head.

    Makes me wonder.

  9. #9
    Boolit Master

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    Is that the case neck pointing back towards the shooter in the last photo ?

  10. #10
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    toallmy, yes you're looking from the muzzle ("wrong" end LOL) towards the breech.

  11. #11
    Boolit Master 243winxb's Avatar
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    High Round Count = Kaboom

    4,000 to 5,000 degrees F at each firing may change steel.
    The temperature required for annealing should be slightly above the critical point, which varies for different steels. Low-carbon steel should be annealed at about 1650 degrees F., and high-carbon steel at between 1400 degrees and 1500 degrees F. This temperature should be maintained just long enough to heat the entire piece evenly throughout. Care should be taken not to heat the steel much above the decalescence or hardening point. When steel is heated above this temperature, the grain assumes a definite size for that particular temperature, the coarseness increasing with an increase in temperature. Moreover, if steel that has been heated above the critical point is cooled slowly, the coarseness of the grain corresponds to the coarseness at the maximum temperature; hence, the grain of annealed steel is coarser, the higher the temperature to which it is heated above the critical point.
    http://www.zianet.com/ebear/metal/heattreat5.html

    Remember the Sako recall years ago. Heat treating not correct. Or the 1903 actions heat treating.

    All guns wear out , soon or later.

  12. #12
    Boolit Master



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    It is definitely a case of the Barrel being stressed over it's ability to contain the pressure. Note in picture one and three that the rupture is fairly straight down the barrel; with what almost looks like a "Seamed Edge" along each side of the linear rupture. In picture three; there are regularly space serrations inside the barrel - these are the to of the lands and grooves. The barrel did not split along what would be considered the weaker area where the grooves are.

    Another interesting observation; the rifle is still highly blued (Picture #1) with no apparent real wear on the barrel and receiver after 50,000 rounds. The stock is in great shape (for a loaner that many club members would use/abuse).

    Many references cite that after 10,000 to 20,000 rounds a .308 Barrel will be "Shot Out". One sees same references for Military rifles. One wonders if these references are too conservative, or is the Club Loaner an "Obvious Overuse that should have been addressed".


    My thoughts are along the path of a squib load followed by a full load hitting obstruction in barrel. Not sure that there isn't some other unreported problem with this rifle though given the rupture area being fairly straight and that problematic surface seam I see coupled with a really good blue job.
    Last edited by MUSTANG; 10-20-2018 at 10:14 AM.
    Mustang

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  13. #13
    Boolit Master
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    Well it is certainly possible that metal fatigue could have caused it. But 50,000 rounds would likely have the headspace get larger as the bolt lugs wear down too. The rifling is getting pretty worn down too. Is it possible to shoot a high powered rifle more than 10,000 times before the rifling is worn down too much? I tend also to suspect that there may have been a squib load and the bullet obstructed the barrel. Then the next round fired did the rifle in. But then stuff does happen, maybe the barrel had a obscure defect or fault that finally manifested itself.

  14. #14
    Boolit Master


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    There is something amiss in the pictures. The picture in the chamber shows both Weaver tightening nuts on the right side of the action. The front scope mounting ring has the band screws on the same side as the tightening nut. But one picture shows the band screws on the left side of the action. I don't think that is possible with Weaver mounts. I may be wrong.
    The bolt shows a large bolt knob that indicates rapid follow up shots. My guess is a squib load followed by a live round or other barrel obstruction such as mud or snow. The fracture looks "clean" across the cross section of the fracture. A fatigue crack would start and the older section of the crack would become discolered with powder and possibly rust. It appears the fracture took place at once and fatigue was not the issue. The jagged edges also indicate the metal was "bent" and intact when the fracture took place.

  15. #15
    Boolit Master

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    Quote Originally Posted by Lance Boyle View Post
    But as the article points out, there are zero pressure signs on the primer or case head.

    Makes me wonder.
    On the other hand, is the fired brass stuck in the chamber? Is the primer cratered, but not pierced? I'm assuming the rifle was a push-feed Winchester, and the extractor slipped off the rim when they got the bolt open.
    My two cents: Maybe it was something exotic, like a bad factory round. Or maybe it was some wild ballistic fluke due to excessive wear in the throat. Or maybe, just maybe, the last guy who cleaned it left a patch or a brush stuck in the bore. I don't see anywhere in the article if this was the first shot in a string, or if rounds had previously been fired before the kaboom.
    Last edited by 376Steyr; 10-20-2018 at 08:02 PM.
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  16. #16
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    Classic result of a bore obstruction.
    Larry Gibson

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  17. #17
    Boolit Master
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    I'm with Mr. Gibson on obstruction, I would bet there WAS about a 150 or so grains of something about a primer pop ahead of chamber.

  18. #18
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    My 2 cents. With a barrel having that many rounds through it the throat and the first few inches of rifling would be well worn on non existent.The bullet and the pressure wave would have a free run until what rifling remained that would grab the bullet and pressures would then go up. Think they called the slide and stick theory. Frank

  19. #19
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    That one picture to me looks like the case head is a little too deep in the chamber and considering that they don't show the barrels caliber marking
    it makes me wonder if someone put a .308 in an .30-06. Iv'e seen 2 other barrels split lengthwise and both were caused by bore obstructions.
    If a high round count causes this iv'e got some .22lr's that would have split decades ago.

  20. #20
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    "Most likely this rifle has seen somewhere in between of 50 000 and 80 000 bangs without any serious issues like this, and anything has its limits of wear and tear." 50k to 80k through a lightweight Model 70 308???????????????? I am more than a little skeptical of the round count. I am in the bore obstruction camp.

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