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OAL grows during crimping operation

Discussion in '10mm Reloading Forum' started by OhioGlockMan, Oct 29, 2010.


  1. OhioGlockMan

    OhioGlockMan
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    Hey everybody, I just made an observation. I've been loading 200 gr. hardcasts with 10 grain blue dot. Ok- I seat the bullets to 1.26 OAL-, then after I run them through the lee factory crimp die (one full turn for a tight crimp), the OAL grows to 1.27. I've been shooting this load for a long time now and don't have any problems with it, its a nice full power load, no pressure signs etc. I'm just wondering why in the heck it grows, and is a max oal of 1.27 going to harm my glock 20, I have a 6 inch wolf barrel by the way?
     

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  2. _The_Shadow

    _The_Shadow
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    In the process of the squeezing of the LEE FCD it forces the cast bullet to a smaller diameter...therefore it gets longer, it is also getting longer inside the casing aswell. If they are chambering fully without hitting the rifling you should be fine. With the bullet is being re-sized to a smaller diameter this could cause leading issues for your barrel.

    My question is do the bulles actually turn inside the crimped case?

    I recently loaded some cast bullets (0.401") and I have found them to turn inside the casing after taper crimping...I have never had this happen before and trying to reslove this situation with seating die adjustments. This may actually be the same thing you are experiencing with the bullet being reduced in diameter.
     

  3. OhioGlockMan

    OhioGlockMan
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    Wow, I've been using the lee factory crimp dies on a variety of calibers with lead bullets for years and had no idea they would reduce the diameter of the bullets. For what its worth I've never noticed any accuracy problems. I wonder why Lee doesn't make an advisory about this issue?? I hope others chime in on this.
     
    #3 OhioGlockMan, Oct 29, 2010
    Last edited: Oct 29, 2010
  4. anomad

    anomad
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    The way I learned was to measure final OAL after crimping. I guess my "teachers" had already been down that road.
    Anyway, I've never let a couple 0.01's bother me, unless we are talking about precision rifle loads.


    Shadow,
    I've seen bullets turn in cases that were ridiculously over-crimped. Where it was crimped so hard it bulged the case out. (I doubt that is your case)
    Maybe back off to just a little kiss from the crimp die and work down to as firm a crimp as you are looking for from there. Is there a reason to crimp any more than just enough to remove the "flare" for an automatic cartridge?
     
  5. B__

    B__
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    I run all my handloads through a Lee FCD and I just recently started reloading cast. No issues with leading or loose bullets in the 500 or so I have used up so far. Damn things sure are smokey though. I'll be buying jacketed/plated again next time around.
     
    #5 B__, Oct 29, 2010
    Last edited: Oct 29, 2010
  6. OhioGlockMan

    OhioGlockMan
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    Ok update, I just loaded a test round with the same 200 gr hard cast and 10 gr blue dot and this time seated it to 1.250 OAL and crimped it with a regular taper crimp instead of the lee factory crimp die. I measured it after crimping and it was still 1.250. Ok this is where things get weird- the next morning I checked the OAL and it grew to 1.263 HMMMMMM- Now I'm thinking the charge is compressed and that has something to do with it?
     
  7. B__

    B__
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    The charge would have to extremely compressed to overcome the neck tension. Are you measuring the same round each time?
     
    #7 B__, Oct 30, 2010
    Last edited: Oct 30, 2010
  8. _The_Shadow

    _The_Shadow
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    Yes, I have seen the over crimp situation, but this is not the case with these, These were Federal cases whith small pistol primers that were fired from the HK MP-5-10 that I reconditioned using the LEE FCD as a pass thru die, then resized via an RCBS die to deprime...These rounds drop very freely into a cartridge case gauge so they are not bulged. With them lightly crimped I could actually pull the bullet outward and remove it. I actully re-seated and crimped them heavier to see if they would tighen up...the edge of the case started to cut into the cast bullet slightly and this keeps them from pulling out or pushing in, however they will turn inside the casing. BTW, this is with 8 Federal casings doing the same thing!

    I will play with things again to see what gives!
     
  9. MSgt Dotson

    MSgt Dotson
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    Either your bullets are too small, or your resizing die is not doing it's job....
     
  10. _The_Shadow

    _The_Shadow
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    Well got it figured out...in the process of re-sizing of these brass shot from the HK MP-5 10mm they stretched slightly that and the expander plug need some re adjustment, we are talking backing it out with a very small adjustments. BTW I have used this expander setting since 1990, I may have tighten it while screwing the die into the press. This led to over expansion of the case mouths, hence the loose fit.:dunno:

    The fix I used was to once again re-size the few cases I had expanded then with the expander re-adjusted the bullets could be seated with the proper neck tension as not to turn or slide in or out.

    I also seat to depth without crimp being applied in one step and then crimp in a seperate step.

    Problem solved!:cool: