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Thread: What causes this type of jam and was I correct in my diagnosis

  1. #1
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    What causes this type of jam and was I correct in my diagnosis

    I was at the range today and met a guy there that was shooting his new Bushmaster Carbon-15 (the model with the polymer upper and lower). It was a new gun, his second time shooting it, but after just a few shots it jammed on him. When I went to help him clear it I found a jam I've only seen once before.

    The live round had managed to jam itself with the rear of the case on top of the bolt up against the gas tube. He tried pulling the charging handle to the rear but all it did was pull the entire live round on top of the bolt inside the upper with the rear of the case jammed against the gas key and the bullet itself jammed against the gas tube.

    Obviously we couldn't just separate the upper from the lower because the BCG was stuck halfway in the buffer tube and halfway in the upper. I had to remove the buffer tube assembly, stock end plate, castle nut, etc. to take enough pressure off the BCG to separate the upper and the lower just to clear the live round.

    After clearing it and reassembling the lower I noticed that the gas key and gas tube were damaged by the live round. The top of the gas key was bent inward and the gas tube was bent up and edges were bent in. Both were damaged in such a way that the charging handle made contact with the gas tube when reassembling and there was not enough space for the gas key in between the handle and tube so reassembly was impossible. So his jam turned into needing a new gas key and gas tube.

    He was using a brass catcher and reloads and thought that had something to do with the jam but I disagreed. My thoughts were that since he was using a standard carbine buffer it was too light causing the BCG to move too fast thus causing bolt bounce; which caused the round to get jammed on top of it. I told him that once he got his gas key and tube replaced he needed to buy an H-buffer from Bravo Company to avoid this again in the future. Hopefully some of yall that know far more than me have seen this type of jam so you at least know what I am talking about.

    So what causes this and whats the solution. Am I correct in my thinking?
    Last edited by HeliPilot; 01-05-11 at 19:19.

  2. #2
    VMI-MO Guest
    It sounds like bolt over ride or charging handle impingement (I get the two mixed up).

    Easiest way to fix it is to:
    Remove magazine
    Tilt the barrel forward while keeping it in a safe direction
    Pull back the bolt as much as possible to the rear, then press down hard on the bolt catch to put pressure on teh bolt and keep it back.
    Karate chop the charging handle forward and the case shoudl fall out.


    This should help


    ETA: THe onlt times I have ever seen this type of malfunction is when brass has bounced back in the gun while shooting in unconventional positions
    PJ
    Last edited by VMI-MO; 01-05-11 at 19:23.

  3. #3
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    Casing stuck between bolt carrier and charging handle. 1. Put rifle on safe. 2. Remove magazine. 3. Do not pull charging handle. 4. Insert cleaning rod section/screw driver or similar tool (I've even used my pinky finger) in ejection port and pull bolt back. Casing should drop through mag well.

  4. #4
    VMI-MO Guest
    Quote Originally Posted by Cagemonkey View Post
    Casing stuck between bolt carrier and charging handle. 1. Put rifle on safe. 2. Remove magazine. 3. Do not pull charging handle. 4. Insert cleaning rod section/screw driver or similar tool (I've even used my pinky finger) in ejection port and pull bolt back. Casing should drop through mag well.

    Just curious why you say not to pull the charging handle?

    PJ

  5. #5
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    Quote Originally Posted by VMI-MO View Post
    Just curious why you say not to pull the charging handle?

    PJ
    The casing is stuck between the front of the charging handle and the BCG. If you pull on the charging handle, you can end up jamming the casing even more and getting it stuck to where you have to reach in there and pry it out.

  6. #6
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    Quote Originally Posted by VMI-MO View Post
    Just curious why you say not to pull the charging handle?

    PJ
    With the casing being jammed between the bolt carrier key and the charging handle, pulling the charging handle just jams the casing in tighter making it more difficult to clear the jam. The bolt needs to be retracted without using the charging handle. Having the charging handle locked fully forward stops the charging handle from moving when the bolt is retracted manually (not using charging handle).

  7. #7
    VMI-MO Guest
    I see your points, but I have never experienced the use of the charging handle making the problem worse.

    Please check out the link I posted in my first post to clarify the technique I am referring to, to see it in action.


    PJ

  8. #8
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    This is called a "type ate malfunction" or bolt override. One of the less common malfunctions but one of the more trouble some to undo.

    Best way to clear is to pull back on charging handle just enough to get some sort of tool on the bolt face to apply pressure on bolt. Then push for ward on CH this should get it lose.

  9. #9
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    Quote Originally Posted by VMI-MO View Post
    I see your points, but I have never experienced the use of the charging handle making the problem worse.

    Please check out the link I posted in my first post to clarify the technique I am referring to, to see it in action.


    PJ
    I've seen that video before. If you watch carefully, you will notice that the casing is stuck between the bolt face and the front of the charging handle. Moving the charging handle will not jam it more in this case.

    Sometimes the casing ends up completely above the bolt. Using the charging handle in this case could wedge it in even more. FWIW, I've had it happen to me twice just shooting off the bench. Once on a range rental Colt and once on a Bushmaster. But, this type of malfunction is exceedingly rare.

  10. #10
    VMI-MO Guest
    Quote Originally Posted by beavo451 View Post
    I've seen that video before. If you watch carefully, you will notice that the casing is stuck between the bolt face and the front of the charging handle. Moving the charging handle will not jam it more in this case.

    Sometimes the casing ends up completely above the bolt. Using the charging handle in this case could wedge it in even more. FWIW, I've had it happen to me twice just shooting off the bench. Once on a range rental Colt and once on a Bushmaster. But, this type of malfunction is exceedingly rare.
    Both charging handle impingement (round is on the bolt face angled into the CH) and bolt override (round completely over the bolt) are adressed in that video and fixed with a similar course of action as demonstrated by that video.

    Also Micheal Pannone in his writing describes the fix in the same way.


    PJ

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