Too much crimp?

Discussion in 'Reloading' started by XDRoX, Feb 20, 2010.

  1. XDRoX

    XDRoX

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    I'm still learning the basics of reloading and want to learn more about crimping.
    What I already learned:
    Too much crimp will get a bullet stuck in the crimping die:whistling:
    This is how I have been crimping my last couple batches. They shoot fine. So far 100% reliable. But am I still crimping too much? I took a photo. The round on the left is a factory Winchester, the round on the right is one of my reloads. You can obviously see the crimp is much more noticeable on the reload.

    Is this OK? Can it potentially cause problems? Any other crimping info would be great.

    Thanks

    [​IMG]
     
  2. Kentucky Shooter

    Kentucky Shooter NRA Life Member

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    The RCBS directions say the top of the case neck right below the bullet should measure several thousandths less than the case closer down toward the base. I don't think it takes a lot of crimp to serve the purpose unless you have some really hard recoiling rounds.
     

  3. XDRoX

    XDRoX

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    Thanks for the info.
    With the factory round if I run my fingernail down the bullet there is a sharp edge of the shell that my nail hits.
    On my reloads that edge is slightly curved in a bit, which I believe you can see in the picture.
    Should I try to avoid this "curve"?
     
  4. Poppa Bear

    Poppa Bear Protective G'pa CLM

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    Pull one and check the bullet. If the bullet is showing signs of deformation then you are putting on to much crimp. If the bullet looks like one that was never used then you are good to go.

    You want just enough crimp to take out the bell put in by the powder/ bell die.
     
  5. XDRoX

    XDRoX

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    This is what I wanted to know. I did pull one and you can see a mark where the crimp was. I will ease off a bit.

    Are the rounds that I already made safe to shoot. I assume since I already shot a lot of them and there wasn't any problems I'm OK, but could it cause a problem?

    I'm not coming close to hot loads by any means. I'm about right in the middle in regards to the amount of powder I'm throwing.
     
  6. Suburban

    Suburban

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    Assuming that's 9mm Luger, and not something exotic, you really don't need a real crimp. At least that's my experience after 10,000+ rounds. You can just straighten out the mouth of the case where the flare die opened it up.
     
  7. BK63

    BK63

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    Like they all said, you are just taking the flare bell out of the casing. I usually check it with a caliper and you want about 3 thousandths difference after taper crimp.
     
  8. HAMMERHEAD

    HAMMERHEAD

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    Make sure you are using a bare minimum amount of flair prior to bullet seating and just enough crimp to remove that flare.
    On my 9mm and .38 Super jacketed loads I do not flare/expand the case mouth at all or crimp after the bullet is seated. I just resize/reprime, charge, seat, done.
    Most factory ammo is not crimped either, some is.
     
  9. Boxerglocker

    Boxerglocker Jacks #1 Fan

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    I know alot of people advocate the pulling of the bullet check for a mark method. If you want to do this fine, just do youself a favor and MEASURE the bullet crimp prior. That way if your dies get messed with you will know they exact value range for your crimp setting.

    Crimp is equal to bullet diameter plus two times the case thickness

    .355 + (0.012 X 2) = .379 would be no crimp at all.

    .379 - 0.002 = .377 crimped

    I like the 0.377 +/- 0.001 target value cause it account for variations in mixed brass, something the pull the bullet method does not do.
     
  10. XDRoX

    XDRoX

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    Thanks for all the info guys.
    Just one more question.
    Is it safe to shoot the crimped rounds that I already made?
    Thanks
     
  11. robin303

    robin303 Helicopter Nut

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    I say yes. I crimp my 9mm and get an average of 0.376 to 0.377 and shot many with my G19. As stated above I have pulled the bullets of every factory round and I don't think they even crimp.
     
  12. Boxerglocker

    Boxerglocker Jacks #1 Fan

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    If you measure them and they aren't grossly out of the 0.375-0.379 range they shouldn't be a problem.
     
  13. XDRoX

    XDRoX

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    They're .377:cool:
    Thanks