To crimp or not to crimp

Discussion in 'Long Range Hunting & Shooting' started by LexRick, Jul 22, 2019.

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  1. LexRick

    LexRick Active Member LRH Team Member

    Jul 15, 2019
    I'm reloading 7m stw should I put a lite crimp or no crimp at all. Not sure what is best practice. Any help would be greatly appreciated.
  2. YZ-80

    YZ-80 Well-Known Member

    Feb 20, 2019
    I wouldn’t but admittedly, don’t have experience with that specific cartridge. The only things I crimp for are my .38/357 and 7.63x39 (SKS & AK) reloads. Unless I absolutely have to, I never crimp and routinely ignore cannelures for bullets like SSTs and let consistent (and sufficient) neck tension do the job.
  3. e1harris

    e1harris Well-Known Member

    Jan 9, 2017
    I don't crimp unless it's magazine fed.
  4. Vol1975

    Vol1975 Well-Known Member

    Feb 6, 2017
    Typical I don’t. But on guns where I have a lot of jump to the land I have played with crimping and not to crimp. I crimp 2 rifles and have seen a slight improvement in accuracy and SD. The only problem is keeping everything consistent. Can be difficult.
    But general I don’t because I just typically play with neck tension. Personally I would stick with playing around with neck tension. It’s more constant in my opinion.
  5. cohunt

    cohunt Well-Known Member

    Jan 21, 2016
    Last edited: Jul 29, 2019
  6. Deputy819

    Deputy819 Well-Known Member LRH Team Member

    Sep 24, 2016
    Have to agree with these guys. I don't crimp either...not even on .358 Winchesters and such. Now, I've only tried it once on a .338-06 I used to own/shoot and it made no significant difference for me in target results or SD/ES numbers for that rifle. Haven't seen the need to try it out again....
  7. dougduey

    dougduey Well-Known Member

    Apr 11, 2011
    I crimp everything. Learned about it from the guys on the 7STW thread when I purchased my 7STW. There is a bunch of debate, but it has shown to make the groups a little better and drop ES for a few guys that did testing. It's up to you, but it won't hurt anything. Also, everyone that is crimping is using the Lee Factory Crimp Die
  8. lancetkenyon

    lancetkenyon Well-Known Member

    Jun 3, 2013
    If the bullet of choice has no cannelure, don't crimp it.
    I don't crimp anything, even my .223 ammo I run in my AR. Not even Hammers or LRX/TTSX with the drive bands/grooves.
    I see no real way my groups can improve over this with a crimp. Various 3 shot groups from different rifles.
    Last edited: Aug 2, 2019
    Barrelnut and Deputy819 like this.
  9. CO_Guy

    CO_Guy Well-Known Member

    Nov 16, 2018
    For rifle loads, I see the need to crimp when you have the situation where neck tension is not enough to keep the bullet from moving under recoil, or the neck tension is not uniform. The throat of your 7STW is short (comparable to the 7rem mag) but not as short as that for my WSMs, and may respond well to crimping. For comparison, take a look at the throat length of a 7mm Weatherby.
  10. Mike AVM

    Mike AVM Well-Known Member

    Feb 15, 2018
    I ran a test with and without a Lee Factory Crimp and found the crimped rounds more accurate by about 25%. If you shoot a magnum with a compressed charge and don't crimp with 0.001 or 0.002 neck tension, I bet the last round in the mag has moved a bit....
    CO_Guy likes this.
  11. Varmint Hunter

    Varmint Hunter Well-Known Member

    Dec 26, 2001
    Crimping adds another variable to reloading which can (potentially) improve or degrade accuracy. If your cases aren't EXACTLY the same length then the amount of grip produced by crimping will vary. That just can't be good for accuracy. But ..... with cases that are as close in length as possible I can see that crimping could be beneficial in some applications.

    I only crimp 45-70, 458 SOCOM and handgun ammo. I don't crimp the 223 cases on the ammo used in my AR because there seems to be no reason to.
    CO_Guy likes this.