CRIMPING -( TO CRIMP OR NOT TO CRIMP )

Discussion in 'Caliber Talk: Ammunition, Reloading, and Shooting ' started by Marine One, Oct 5, 2018.

  1. Marine One

    Marine One New Member

    16
    Sep 27, 2018
    Hi Guys, That is the Question?
    In my case I have a 9mm 1911 and bullets I'm using do not have a canntalour,I was
    told that if you have a canntalour on your bullet you don't need to crimp. But with a
    auto
    matic and a kick back don't you crimp???

    what do you Think??
     
  2. pscipio03

    pscipio03 Fun O' Meter on FULL

    Mar 11, 2013
    Unless you're going full auto, any crimp in a 9mm is pretty much overdoing it.
     

  3. mikegalway

    mikegalway CEO of DILLIGAF industries Supporting Addict

    Feb 23, 2014
    On 9mm and 45 acp I use the Lee factory crimp and sizing die . Seems to insure flawless function . Most 45 acp and 9mm bullets I come across don't have a cannelure .
     
    kc1911, Mike0251 and 41 Charlie like this.
  4. Dwe

    Dwe I'm a terminal 1911 Addict!

    Sep 4, 2011
    For 25 years I’ve always used a slight taper crimp on all auto cartridges,
    and I’ve never had issues. I find OAL is a more critical factor.
     
  5. Karsten

    Karsten Well-Known Member

    Feb 19, 2013
    Forgive me but as I recall Swaged Bullets had a Wax Ring where a Cannelure was found on USGI 5.56 rounds to make the bullet tumble and break apart on impact causing more interior damage to tissue on impact.

    Karsten
     
  6. apipeguy

    apipeguy Well-Known Member

    766
    Feb 28, 2014
    Been reloading since the 70’s and the above is correct. The crimp does not hold the bullet, a properly sized case does. Probably removing the flare is really all that we are doing. I’m at about .377-.378 for 9’s and .470 for 45’s.
     
  7. noylj

    noylj Member

    72
    May 20, 2012
    Revolvers need a roll crimp (where the case mouth is turned into the cannelure) since the recoil action tends to pull the bullet out of the case.
    Semi-autos don't have this recoil impulse, with feeding being the action that can push a bullet into the case. Since the case is supposed to head-space on the case mouth, you DON'T want a roll crimp, just a taper crimp. The taper crimp is really only there to remove any case mouth flare and NOT to hold the bullet--it is really just a feed-and-chamber issue.
    Best thing for a semi-auto is to immediately try to push the bullet deeper in the case with thumb or finger pressure and reject any rounds where the bullet moves even slightly. Then, just taper enough so the rounds all chamber. If you look at factory rounds, you'll see the case mouth is just straight and NOT turned into the bullet at all.
     
  8. Dave Jessee

    Dave Jessee Well-Known Member Supporting Addict

    825
    Dec 31, 2014
    Do you have a crimp die? If so which one do you have?
     
  9. xerts1191

    xerts1191 Well-Known Member

    Aug 12, 2017
  10. Dwe

    Dwe I'm a terminal 1911 Addict!

    Sep 4, 2011
    Dillon makes the taper crimp dies I’ve been using.
    Dillon die sets include separate seating and crimp dies.
     
    BigJimP likes this.
  11. Dave Jessee

    Dave Jessee Well-Known Member Supporting Addict

    825
    Dec 31, 2014
    Trying to figure out if the OP has a roll crimp or taper crimp die. Or even a crimp die at all. I have a Dillon taper crimp for 9mm and a Redding taper crimp for 45acp. Both for my 550 and Redding T7.

    Crimping is probably the easiest of all my dies that I set.
     
    Dwe likes this.
  12. kc1911

    kc1911 Member

    66
    Jul 13, 2018
    I'm a big fan of the Lee Factory Crimp Die (FCD) for both revolver and auto-loaders.

    For auto-loaders I put in just enough taper crimp to remove the case flare and to reliably pass the plunk test on my tightest barrel.
     
  13. pistolpete

    pistolpete Well-Known Member

    352
    Mar 12, 2016
    I put a slight taper crimp on 9mm and .45. It seems to help with feeding.
     
  14. El Perdido

    El Perdido Fictional Western Sage

    Oct 3, 2011
    My "crimp" die on my 550 is set to give me .470 at the case mouth. Basically removing the bell. Zero (0) feed issues in my Colts or my Baers.
     
  15. switchback

    switchback Well-Known Member

    Jun 2, 2014
    Yep, agree with the Lee factory crimper. It does add another step, but I use a single stage anyhow, so...
    Never have a problem with just a slight crimp, and a proper coal and properly sized case is critical. The Lee crimper just makes it perfect, IMHO
     
  16. 1911KY

    1911KY Shooter Ready.....Stand By!

    Mar 20, 2015
    I crimp all my 9mm rounds.
     
  17. Gary Wells

    Gary Wells Active Member

    263
    Sep 26, 2011
    Not passing judgement here, but I am on the lazy reloader side and taper crimp with a Dillon taper crimp die just enough to remove any bell mouth and that seems to be about .469-470 with an occasion round going to about .471 on the calipers. Some of the B/E shooters over on "Bullseye-L-Forum" believe that crimp plays an important role in accuracy and crimp down to about .465-.466. I believe that the late great gunsmith Jerry Keefer was one of those that believed in a heavy crimp for accuracy and did some experimenting accordingly. This line of thinking is probably predominant among the lead shooters.
     
    Last edited: Oct 13, 2018
  18. Busa Dave

    Busa Dave Well-Known Member

    Mar 3, 2018
    LOL no -- have no idea where that one came from.... :)

    Not even possible with FMJ in that round to make it "break apart". Pretty funny the wild things people put on the internet.

    Read this for some background in military ammunition. It is a pretty good summary of how the requirement for FMJ initiated from and where it is today. The new Sig striker pistol for the military has as part of the contract to supply ammunition and it is hollow point. On rifles the JAG made a ruling that the SMK HP was not a expanding by design hp and as such was compliant. One reason you will never see in writing by Sierra anything that states the SMK is anything but a target bullet. They sell a lot of bullets for loading into ammunition for the military. :)

    https://www.icrc.org/eng/assets/files/other/irrc_849_coupland_et_loye.pdf
     
    Last edited: Oct 13, 2018

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