How can you tell it you have crimped too much, or not enough?

Discussion in 'The Ammo & Reloading Forum' started by stev32k, Nov 6, 2012.

  1. stev32k

    stev32k Active Member

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    I've been trying to decide how to set the seating/crimping die. The seating part is easy, but there is really nothing to measure for the crimp. I've been giving the cartridges the whack test - that is put them in a hammer type bullet puller and see if it takes a hard whack to get the bullet out.

    That seems like a pretty crude test, but have not really found anything else to go by. The last rounds I pulled had an indentation around the bullet where the case had been crimped and I wonder if this is normal or indicates too much crimp?
  2. soundguy

    soundguy Well-Known Member

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    can i assume you are talking baout a rollcrimp die setup.. like an rcbs might use on a rifle die set?

    the brassh will just start to lay over into the cannelure. too much and you are way overflexing and workign the brass and that will lead to early mouth/case failures.

    do the push in test to see if the bullet cnnot be pushed in by pressing a dummy cartridge into your workbench. if you can get like 50# on it and no setback.. it's held in good.

    excessive crimp isn't desireable.
  3. ozo

    ozo Active Member

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    And too much can cause high pressures.

    I use Lee carbide dies [yes, in my Dillon]
    and mine are an easy adjust....
    Remove the seating adjustment 'pin' or
    at least back it way out......
    Using an empty case, slowly screw the die
    in the tool head, little at a time, checking
    the case mouth with a micrometer.
    Your instructions that came with the dies
    should show you how.
    Last edited: Nov 6, 2012
  4. soundguy

    soundguy Well-Known Member

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    ^^^^^^ YUP

    same with the rcbs roll crimp...
  5. stev32k

    stev32k Active Member

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    My die sets (Hornady) don't give a clue as to how much crimp to put on the cartridge. It tells you how it's done, but says nothing about the amount.
  6. stev32k

    stev32k Active Member

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    How much should the crimp reduce the diameter of the case?
  7. soundguy

    soundguy Well-Known Member

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    that's where the reloading manuals come in.

    On mine.. I crimp till i just see the leading edge of the brass start to aly over into the cannelure, and they also pass a hard push test. if they do that.. they will be fine for no-setback in a magazine.
  8. mikld

    mikld Member

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    Well, what type of crimp are you using on what cartridge? From what is hinted about so far, sepatate the seating from crimping operations (seat all bullets then readjust die and crimp all cartridges).
    Last edited: Nov 6, 2012
  9. stev32k

    stev32k Active Member

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    I'm reloading 9mm and using the Hornady seating and crimping die. The Hornady manual says "use little or no crimp". If I don't use any crimp the bullet is loose in the case. So I tried turning the crimp down 1/2 turn after it made contact with the case. That's where my problem is - is 1/2 turn a little crimp or a lot? Maybe it should be 1/4 or 1/8 or 1 full turn for a "little crimp".
  10. soundguy

    soundguy Well-Known Member

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    ahh.. pistol, not rifle!
  11. 312shooter

    312shooter Active Member

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    A 1/2 turn is good. Excessive resistance on the press handle is clear indicator there is too much crimp. A good way to measure a proper crimp is using calipers near the casemouth after bullet seating, compare the measurement to the dimension of the sum of the bullet and case thickness x2 prior to seating.
  12. mikld

    mikld Member

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    When reloading semi-auto ammo, ferget the term "crimp". You will be using a taper crimp die just to "deflare" the case mouth. All you need is to remove any flare in the case mouth so chambering is easy. Use your gun's barrel (removed) as a gauge. If the bullet is loose in the case prior to "deflaring", there is a problem elsewhere (sizing/expanding/bullet dia.). Again, separate operations; seat, crimp.
    Last edited: Nov 7, 2012
  13. runswiththunder

    runswiththunder New Member

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    I use the Lee Factory Crimp die, so I'm not familiar with the Hornady die. To check my crimp, after seating the bullet I measure the case just at the mouth, then adjust the die to create a crimp of about .005+. To check the tightness, you can place the bullet on the edge of your table and press against the base of the cartridge. If the bullet stays put, with a few pounds of pressure, it's probably crimped sufficiently.
  14. cpttango30

    cpttango30 Guest

    too much crimp and your round will fall into the chamber too much. Just check in your barrel.
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