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Artillery cartridges with primer flash tubes

Discussion in 'Artillery' started by the_diego, Jun 8, 2021.

  1. the_diego

    the_diego Active Member

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    Did any army use this in the war? I'm having difficulty in getting the actual term. Basically, it's a metal tube that begins from the primer pocket of the shell casing and projects upwards into the casing cavity. This tube directs the primer flash upon firing and ignites the propellant powder somewhere in the middle, rather than at the base of the casing.

    Elmer Keith claims to have invented this flash tube together with a friend sometime just before or during the war. They were frustrated with magnum rifle rounds that failed to fully burn the propellant powder. They say you could actually see unburnt powder being expelled out of the muzzle. They realized they were burning the powder from the wrong end. So they soldered thin steel tubes from the primer pocket so that the primer flash would be directed upwards and ignite the propellant somewhere at 1/3 up the casing.

    Keith said the result was, for a given amount of propellant, bullet velocity did not go up. Nor did recoil go down. What happened was you had a tremendous reduction in chamber pressure. Therefore, you can gob in more powder than allowed and achieve higher velocities without risking excessive chamber pressure. They submitted their findings to the Army but the method was not adopted. They were however, told not to divulge their findings (at least at the time.)
     
    Last edited: Jun 9, 2021
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  2. harolds

    harolds Member

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    Elmer Keith claimed a lot of things! Not all of them were true!
     
  3. harolds

    harolds Member

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    I suspect the problem EK had was solved when primer manufacturers came out with magnum primers. Having the primer in the rear was not the problem. They needed more flame and pressure from the primer to get the powder to burn properly.

    However, as far as I know you can't fire a case with a given amount of powder and get the same ballistics with lower pressure- Ain't happening!
    Yes, fixed and semifixed artillery and AT guns often did have a priming tube in them such as you describe. The reason was that the powder grains in arty rounds are larger and harder to ignite. That's why in bagged rounds you often see a small bag of black powder on the end of a regular powder bag. The priming cartridge set off the black powder and that in turn set off the regular powder charge.

    Tubes allowed for more priming compound and also more holes so that the powder charge went off more consistently.
     
  4. the_diego

    the_diego Active Member

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    If EK's metrics are correct, I think the proper conclusion is you get reduced pressures for a propellant with a given % of nitro (rate of burn), and assuming uniform grain size. Therefore, you could use faster rate-of-burn powders safely. That's how you up velocity.
     

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