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Do you recommend crimping the neck on AR15 loads?

Discussion in 'Reloading' started by RMTactical, Aug 25, 2012.

  1. RMTactical

    RMTactical CLM

    Oct 7, 2000
    Behind an AR-15
  2. F106 Fan

    F106 Fan

    Oct 19, 2011
    If the bullet has a cannelure, sure! If it doesn't, there is no need to crimp as long as the resized brass provides adequate neck tension. I think you will find that most reloaders don't crimp .223 if the bullet doesn't have a cannelure.

    We just discussed this a few weeks ago. Perhaps the forum search feature will turn up the thread.

    Here's one of the threads:

    Be aware that this has been debated endlessly with no real resolution. Some reloaders always crimp, some never crimp and some just crimp bullets with a cannelure.


  3. PCJim

    PCJim Senior Member

    Aug 4, 2008
    I'm with F106 on the issue. If there's a cannelure, crimp it. If there isn't, don't.
  4. fredj338


    Dec 22, 2004
    Pretty much how I roll em too. A cannelure bullet gets a mild roll crimp, anything else, nope.
  5. TX Archer

    TX Archer

    Jun 4, 2011
    Austin, TX
    Just curious, Fred. I've recently begun loading .223. Can you quantify a "mild crimp"?
  6. steve4102


    Jan 2, 2009
    I crimp all my semi-auto handloads with the Lee Factory Crimp Die. It helps secure the bullet and increases accuracy. It works on bullets with or without a cannelure.
  7. squirreld


    Jan 15, 2006
    US of A
    Oh no you didn't...........
  8. steve4102


    Jan 2, 2009
    I didn't?
  9. Zombie Steve

    Zombie Steve Decap Pin Killa

    May 31, 2007
    Old Colorado City
    I generally don't crimp .223 loads for the AR.

    If you're going to do it, just barely touch the darn thing. It's really easy to squash the shoulder.

    The AR's action tends to yank bullets out a few thousandths when it comes to an abrupt stop in the chamber. If you find yourself re-chambering a round over and over, a light crimp might be a good idea.
    Last edited: Aug 26, 2012
  10. F106 Fan

    F106 Fan

    Oct 19, 2011
    I don't know how Fred is crimping them but my process is pretty simple. First, when I set the bullet at some nominal OAL, the leading edge of the case mouth is almost exactly at the forward edge of the cannelure. I use the Lee FCD to roll a crimp that just barely depresses the case mouth into the cannelure. It is certainly not bottomed out. In fact, I measure about 0.005" change in diameter.

    The rifle version of the Lee FCD seems to work pretty well as a crimping die. All of the cases are trimmed during case prep so it is pretty easy to get a uniform crimp.

    For no particularly good reason, I set my dies up to reproduce the crimp on the Wally World Federal .223 bulk ammo. Federal is also using a 55 gr bullet with a cannelure so it seemed reasonable to duplicate what they were doing.

    I wasn't overly concerned with the bullet moving forward during chambering but I was worried about it setting back from either chambering or recoil. With the forward edge of the case mouth touching the leading edge of the cannelure, setback should be controlled.

    The nature of my shooting is that when a round is chambered, it will be going down range. I don't think there is much chance of multiple chamberings.

    I also figured that there must be a reason that Montana Gold put the cannelure at that specific location on the bullet. So, I used it.

  11. Zombie Steve

    Zombie Steve Decap Pin Killa

    May 31, 2007
    Old Colorado City
    I'd say see if you can get away with no crimp first. No need to make things more complicated if they don't need to be.
  12. Hoser

    Hoser Ninja

    May 22, 2002
    As long as your brass is the same length, knock yourself out.

    If it is a different length, you will end up with more crimp on some and less on others.

    That said, I don't crimp any rifle ammo.
  13. ColoCG


    Mar 18, 2011
    I agree with Hoser. With a few exceptions on ammo for dangerous game, I don't crimp any rifle rounds including .223's for a couple of AR's.
  14. I used to, but after loading some match ammo with a friend I decided to skip the step. I did not find any ill effect from a lack of crimp at all. Course, did not see any great improvement either...
  15. freakshow10mm

    freakshow10mm 10mm Advocate

    I recommend proper bullet tension. There are two methods: crimping into a cannelure and properly sizing. Both work. I prefer properly sizing to control the bullet tension.
  16. F106 Fan

    F106 Fan

    Oct 19, 2011
    Did you take the opportunity to measure the change in OAL of, say, the 30th round in a magazine to see if any of the bullets set back from recoil? It would also be worth ejecting the last round after chambering and checking the OAL.

    I haven't done any of these measurements but perhaps the next time I am out I will do so. Of course since my rounds are lightly crimped into the cannelure. I don't expect any changes. I might see the OAL get a little longer from chambering but setback shouldn't be a problem.

    With my original SP1 and an 8 to 10# inconsistent trigger, I don't expect much better than 1-1/2" at 100 yards. I'm not sure better grouping is even worth trying.

  17. Boxerglocker

    Boxerglocker Jacks #1 Fan

    Mar 6, 2003
    Lynnwood, WA
    Yes, yes... he did :upeyes:

    I crimp all my target / match 55g stuff. Either Horandy or MG FMJs W/C. I FL size and trim all my brass each and every time though. XL650 with a RT12000B trimmer.
  18. F106 Fan

    F106 Fan

    Oct 19, 2011
    And I copied what you are doing; thanks for the suggestions. The trimmer on a 650 toolhead makes short work out of getting a uniform case length.

    With the Federal brass I am using, very little material is actually removed. In some cases, the mark at the case mouth is only part way around. All I am doing is squaring up the case.