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Specific question on crimping

Discussion in 'Reloading' started by SC_Dave, Dec 8, 2012.

  1. SC_Dave


    Oct 7, 2005
    Florence, SC
    I am sorry to belabor the crimp question but I have little experience and wnat to do it right. I\Just got my 9mm taper/seat crimp die, I adjusted it to remove the flare. However, with the cartridge between my thumb and forefinger I can, with some force push the bullet further into the case. Do I need slightly more crimp?

    Thanks, David
  2. It's been determined in a number of previous posts and threads that the crimp does not hold the bullet in the case. You need more neck tension. Are you resizing properly?

    posted using Outdoor Hub Campfire

  3. dhgeyer


    Jul 15, 2011
    You have way too little case neck tension holding the bullet. Those rounds aren't even safe, as the process of stripping them from the magazine and loading them into the chamber may push the bullet deeper into the case, causing an increase in chamber pressure.

    Crimping will not increase case neck tension. It may slightly decrease it in some cases if you are over crimping.

    However, with that little retention, I would suspect your problem lies elsewhere. Look at some reloaded rounds. You should be able to see where the bullet has expanded the case near the mouth as it forced its way in. In other words, you should be able to see from the outside of the case where the bullet is in the case and where the base of the bullet is. It may not be hugely obvious, but you should be able to see some expansion where the bullet is. If, as I suspect, you can't see this, then you need to look at other parts of the reloading process - not the crimp.

    I would begin by checking your resizing die. It should be very difficult to seat a bullet after resizing but before belling the case. Holding a bullet up against a case that has been through only the resizing die, you should be able to see clearly that the bullet will have to force the sides of the case out a bit to go in. If not, then, something is wrong with your sizing die, or its adjustment. If it's a carbide die and you have the case going in past the neck, then you have a faulty die. If it's not a carbide die, then you may not be pushing the case far enough into the die. See the setup instructions that come with the die set.

    If the resizing die is doing its job, then maybe the expander is opening the cases up too much. Either the plug in the die is faulty, or you are pushing the case way too far up into the die. Again, see the instructions that come with the die set.

    Some will say, shortly I imagine, that you are either over or under crimping, and here we go again! My opinion is that, with as little retention as you have, you couldn't do that much harm by over or under crimping.
  4. SJ 40

    SJ 40

    Jan 17, 2011
    + 1,recheck your sizing die adjustment.Bullet pull/neck tension is what you are lacking.
    If that checks out the next die to check would be your expander,check the diameter of the expander it's self. I have had to reduce the diameter of a expander or two on a couple of die set to get what I wanted. SJ 40
    Last edited: Dec 8, 2012
  5. F106 Fan

    F106 Fan

    Oct 19, 2011
    And then there is the possibilty that you are over-expanding. All you want to do is open up the mouth about 0.020". Just enough to give the bullet a chance of seating without shearing off the plating/lead/jacket.

    Make sure you sizing die is hitting the shell holder when the ram if fully up and cases are in every station. This is a non-negotiable adjustment. The die MUST hit the shell holder. Some people adjust the die another 1/8" turn down so that the press 'cams over' slightly.

    Measure the diameter of the case near the casemouth but back beyond where it will get belled. After belling (expanding), the case diameter should not change.

    Adjust the belling portion of the expander to open the casemouth by just 0.020".

    Adjust the seating die to the proper OAL on an assembled round. Then back the seating plug off by a bunch of turns.

    Adjust the crimp portion of the die (I REALLY HATE seating and crimping in one step) so that it JUST closes up the case mouth.

    With the assembled round back in the die, adjust the seating stem so it just touches the bullet.

    That you are dragging on the seat/crimp die on the way out seems like you have something wrong in the adjustment. After all, a 0.020" belled case went up into the die and now the case is probably smaller after the bullet is seated and it's dragging?

    I suppose it's worth knowing which dies you are using.

    Last edited: Dec 8, 2012
  6. SC_Dave


    Oct 7, 2005
    Florence, SC
    F106, I checked my expansion and it is dead on 0.020 difference. My sizing die is touchinf the shell plate, I double checked. I re-adjusted the seat and crimp as you suggested, I'll give that a try and see how it goes. My main issue is lack of experience. Thanks, David
  7. fredj338


    Dec 22, 2004
    As noted, crimp does NOT hold the bullet. In fact, too much can cause loss of neck tension. Make sure the dies are set correctly, then pull a crimped bullet & check it, make sure there is no defined mark where it was crimped. Check the bullet dia, yes sometimes they send you undersized ones. Check the expander dia, it should be no larger than 0.03535". If so, polish that down a bit.
    Last edited: Dec 9, 2012