pressure difference from lot to lot of retumbo

Discussion in 'Reloading' started by wolverine99, May 30, 2011.

  1. wolverine99

    wolverine99 Well-Known Member

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    I was using a little retumbo from a friend to see if my gun liked it, and it did so i ordered a keg of it. I know that there are differences in lots but I had to back down from 56.6g of my friends lot of retumbo to 54.5 of my retumbo. Is that a lot or is it normal
     
  2. loaders_loft

    loaders_loft Well-Known Member

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    2 grains? What made you decide to back off? Velocity, pressure signs, group size, etc??

    That just doesn't seem right. Check everything - I bet something else is going on...
     

  3. wolverine99

    wolverine99 Well-Known Member

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    that is with all the same primers, seating depth, case lenght haven't change a thing. 55g is still showing ejector button marks. Any thoughts? I am shooting at 1000-1200 feet higher elevation than when I was using my friends powder.
     
  4. cowboy

    cowboy Well-Known Member

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    Same scale on both loads??? Something isn't right.
     
  5. cornstalker

    cornstalker Well-Known Member

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    Was the ambient temperature or ammo temperature significantly different from first attempt to second?
     
  6. boomtube

    boomtube Well-Known Member

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    The normal lot to lot variation of cannister powder is usually quite small, your difference IS a bit more than I would expect. Wonder if you chronographed any of the two loads?
     
  7. loaders_loft

    loaders_loft Well-Known Member

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    What chambering and rifle?
     
  8. highridge1

    highridge1 Well-Known Member

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    I can believe it , I had a newer lot of H1000 that I had to back off 4 grains from a proven load. I am not using H1000 and retumbo anymore ,too much variation. I went back to RL25 which I have used for years in many magnums, and the issues went away.