Different powders and barrel erosion

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by weaverism, Sep 26, 2003.

  1. weaverism

    weaverism Well-Known Member

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    Aug 12, 2003
    I know two people who have had visible barrel damage from using W760 after as few as 20 rounds. I've also heard that Reloader brand powders have caused barrel bore damage. What powders or brands of powder have caused barrel damage and should be avoided?

    [​IMG]
     
  2. DANTEC

    DANTEC Well-Known Member

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    Jul 6, 2002
    general rule is ( following Vaught )

    3 factors
    mecanical erosion ( sand blasting )
    thermal effect
    plasma effect


    coarse tubular powder as 5010 ( not in production now I think ) that a good powder ( SD ) but grain of powder seem to make sand blasting in the throat

    "hot" spherical powder , some ball powder ( very hight rate in nitro ) are very hot when they burn as example some old lot of SP7 ball powder ( french made powder ) [​IMG]
    are so hot that you can see throat erosion after 400 rounds in 308 WIN slow fire ( not really a wild wildcat the 308 win )
    now SP7 is more quiet by adding graphite but that a durty powder ( too much graphite )

    some other facts seem right :
    machine gun firing rate increase steel skin temperature up to resistance specs and you get very fast wear / erosion .

    long neck with right ( sharp )shoulder angle are better for throat life , powder burn in neck not in throat , that seem logic

    I am interesting to get other information on powder / barrel life too

    good shooting

    DAN TEC
     

  3. daveosok

    daveosok Guest

    Hey Dantec how have ya been?
    I talked to Dan Lilja about barrel errosion. Rate of fire, time of exposure and tempreature were the three factors he talked about most causing throat errosion.
    I have heard where some barrels have Stellite spray welded on them, I've worked with this stuff and it is hard, hard to machine and hard to grind. Use to make pins for pushing out the old style headlights. Thoses four protrusions on the backside of a older style headlight were done with Stellite pins.
    That could be a solution but since it is so hard to work with youd need some specialized equipment to get a good chamber and throat.
    Dave
     
  4. DANTEC

    DANTEC Well-Known Member

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    dear daveosok

    I am ok but very busy

    stellite is use too mostly for valve seat on big diesel turbo engine , that a colbalt alloy very difficult to machine , army barrel in 50 cal use now stellite insert in FN factory barrel

    some other solution are developed , Accuracy Int use a special coating ( surface hardneder look as vacum nitrated process ) to increase barrel life on German sniper rifle in 300 WIN mag

    but a well design case and a moderate rate of fire can easy increase barrel life

    good shooting

    DAN TEC
     
  5. MAX

    MAX Well-Known Member

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    Sep 10, 2001
    An opinion put forth by M.L. McPhereson which I agree with is that erosion is a function of pressure and little else. The temps are not high enough, the duation too short. There is a direct correlation between the pressure curve as relates to barrel length and erosion, which according to him is actually corrosion. That's another subject for later. See Issue #46 or #47 of VHA Magazine for the entire story.