To crimp or not to crimp?

Discussion in 'Reloading' started by H2OFUZZ, Apr 3, 2011.

  1. H2OFUZZ

    H2OFUZZ Well-Known Member

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    I am shooting the 180SMK out of a 7mmSTW at 3140fps would you guys recommend crimping or not? Also do you think that is a good speed for this caliber? Thanks in advance

    H2o
     
  2. backwoods83

    backwoods83 Well-Known Member

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    With that much grunt already, use a crimp and you will hurt yourself and the rifle.
     

  3. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Crimps are fine and dandy for some applications, even necessary for one or two. But for the most part, they're a waste of time if you've got adequate neck tension. They hurt accuracy more often than they help it, but that might be something you want to experiment with. It means an extra step in the reloading process, and whichever type you chose (assuming you do), move in small increments and see what effects it has.
     
  4. H2OFUZZ

    H2OFUZZ Well-Known Member

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    Ok good to know. I have not been crimping so i think ill keep up with the way i have been doing it. Thanks for all the help.
     
  5. bowhunthard

    bowhunthard Well-Known Member

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    I recently started crimping my .308 Win. with the Lee Factory Crimp Die. Since then I have noticed a tighter ES and SD reading thru my chrony (low teens ES, like 7-8 SD). No real difference in accuracy, but maybe an average velocity increase of about 20 FPS, I'm gonna try doing this to my .22-250 next. We'll see what happens with that.

    I don't anneal my cases yet, I don't believe you have to crimp if the cases are annealed and the neck tension is uniform.
     
  6. 338winmag

    338winmag Well-Known Member

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    I was on board initially regarding using Lee Factory Crimp dies but now I am on the fence trying to decide if it is even worth the ammo and testing time.

    The Positive:
    I "think" I got closer ES groups. The reason I say "think" is because one just can't tell with 20 rounds. One would truly think with the logic that smaller ES, the tighter the groups. Again I think I got tighter groups but will have to test some more.....

    The Negative:
    I work extremely hard in my reloading to get everything as consistent and exact as possible and that goes for my seating depth (for every single bullet). regardless if there is or is not a cannelure, using the Lee Factory Crimp die can and does move the seating depth. If moved, it can be +- .003-.007. Sometimes it doesn't affect the bullet seating depth. If this was predictable, then great, i could take that into consideration when performing the initial seating depth, but it is not.

    I called Lee and asked about this. I get an affirmative that it can affect bullet seating depth. So one might get smaller ES groups but if one is changing the seating depth, you can increase your POI groups. Like any other tool, I might probably find the very happy medium for each caliber, but then again not so sure so .......

    Thanks
    3382Winmag
     
  7. boomtube

    boomtube Well-Known Member

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    "..would you guys recommend crimping or not? "

    Simple question. Simple answer; try it both ways and tell us what happens.

    There's likely to be no real difference at all.
     
  8. bowhunthard

    bowhunthard Well-Known Member

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    In my testing (most of my initial testing is based @ 100 yds., then I extend the ranges), I did not find 0.005" in seating depth to make a large noticeable difference. 0.010 - 0.020" changes in seating depth, made an actual visible difference in group sizes. But, ES is an important factor, although hard to actually validate unless testing through multiple chronys. I'm not 100% sure if I'll keep crimping, because it should not be necessary with regularly annealed brass (consistent neck tension being the goal). Right now, I'm looking into getting some equipment for annealing my brass, because that's one more thing I do want to try.

    I'm not a major expert, so feel free to correct me :).