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Reloading 223 with a Lee Collet neck sizing die

Discussion in 'Reloading' started by DoctaGlockta, Jan 7, 2010.

  1. I have started loading 223 for a single AR-15. So far so good. I have been using a full length Lee resizing die. I have just purchased a Lee neck sizing collet die. Now I have been trolling the interwebs looking for folks that have done this. So far I have found many nay sayers and a few peeps that say it has worked for them.

    Has anyone here used a Collet neck sizing die instead of a full length sizing die for 223 rounds that have been and will be shot in a single AR-15? If so have they had any problems?

    This seems to be a bit of urban myth that the collet will not work with a semi-auto.

    I'm going to load up 20 rounds this way when I get back after the weekend and see how it goes. Will report back if I live to tell the tale.

    Thanks in advance gentlemen for your responses.


    Last edited: Jan 7, 2010
  2. Uncle Don

    Uncle Don Wood butcher

    Jan 24, 2004
    I personally think it's dangerous practice. The harsh handling of the cartridge in a semi-auto requires full length sizing and at least a slight crimp on the bullet.

    The collet dies have a mandrel that is only about .002 less than the bullet diameter. When you account for a 50% springback, the bullet is only being held by .001 tension of the case neck. Furthermore, since the bottom portion of the case isn't sized, it has very close tolerance to the chamber from being fired in there before. I just think that you would be playing with fire and asking fore bullet setback which would dramatically increase pressure.

    My advise is to stick with full length sizing for that rifle, but if you get a bolt or single shot used for target, go for the collet dies - they produce very accurate ammuntion.

  3. Don thanks for your input. I had planned on using a Lee FCD die for a gentle crimp after the bullet is seated.
  4. bush pilot

    bush pilot

    Jan 29, 2004
    If you use the brass fired from THAT rifle and load them one at a time (not from a magazine) they should work. As you'll discover, loading them one at a time will be a PIA and defeats the purpose of a semi-auto.
  5. Interesting. Thanks.
  6. GioaJack

    GioaJack Conifer Jack

    Apr 14, 2009
    Conifer, CO

    Bear in mind that neck sizing works on brass that has been fired in a chamber of a bolt action rifle that it will be fired in again. The camming action of the bolt provides sufficient action to fully seat the round in the chamber without FL sizing.

    Don is absolutely correct in that neck sizing for a semi will cause you more problems than you really want to deal with.

    Back in the '70's when I loaded for an AR I had to use small base dies but I understand that most AR's now have loose enough chambers that standard dies work fine. There are lots of guys around here that have much more experience with the newer guns than I do so they would be a better source of correct information. Good luck.

  7. 10-4. Thanks Jack.