Crimping ?

Discussion in 'Reloading' started by racking on, Sep 12, 2012.

  1. Do you have to crimp handgun reloades for best of grouping on paper at 15-30yds using 9mm G19, also has anyone heard of the consistent crimper at If we do have to crimp will this crimper using lee factory crimp die be worth buying?

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  2. Zombie Steve

    Zombie Steve Decap Pin Killa

    Generally, you'll have to taper crimp to get it to function in a semi-auto, but don't think of it as crimping. Think of it as de-flaring the case. All you're trying to do is straighten it back out. Neck tension holds the bullet just fine.

    Your normal seater die will be able to do this. You might want to do it in two steps, although both seating and crimping can be done at the same time. Just easier to take them one at a time.

    Take your barrel out of your gun and drop a finished round in the chamber. Just crimp enough to get it to drop in flush with the barrel hood. It should fall out freely. That's all you need.

    No need for the Lee fcd or any other fancy crimp dies. .

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  4. SPIN2010

    SPIN2010 Searching ...

    Interesting ... why would you need to crimp straight case based calibers? I would think to just de-flare would be fine. I have never crimped a 9mm, 10mm/.40, or a .45ACP in over thirty years. Curious.
    #4 SPIN2010, Sep 13, 2012
    Last edited: Sep 13, 2012
  5. There are some fine target pistols in this world including the Colt Gold Cup and the S&W Model 52 (not even counting all the great .22s such as the S&W Model 41) but the Glock 19 isn't one of them. Nor was it intended to be!

    One characteristic of a target pistol is a very crisp trigger break with no perceptible creep. The long-creep trigger of the Glock will never make the cut.

    I have to be realistic about my shooting. My eyesight isn't much, my grip is questionable and the trigger on my G21SF just sucks. Still, I can keep the holes in an 8" circle at all practical distances. I can hold the 10 ring at 7 yards so I know the gun will shoot. I am the limiting factor in all my shooting. Not the firearms!

    The Lee FCD isn't highly regarded around here for crimping ANY semiauto pistol cases although is sees some use for crimping revolver cases where the bullet has a cannelure such as .38, .44 MAG, .357 MAG and I'm using it to crimp .223 with a 55 gr FMJ. But any roll crimp die would work just as well and they have done so for many decades.

    In terms of pistol loading, the FCD is supposed to solve a problem that shouldn't exist (improperly sized cases) and creates a problem that didn't exist (over crimping on straightwall pistol cases).

    I prefer a taper crimp die on semiauto cases as a separate operation. Besides testing the loaded round in the chamber (remember, you can fit a bowling ball in a Glock chamber), you should make certain the casemouth of the top round in the magazine doesn't catch on the base of the case being ejected. I place a straightedge along the case to see that the taper has been totally removed.

    Pull a few bullets after taper crimping and make sure the casemouth is not being embedded into the bullet. This is particularly important with plated bullets. The plating isn't very thick and cutting through it does nothing for accuracy.

    As to measuring the torque applied during crimping, I wonder if the brass wall thickness and annealing make a difference. That is, given a few thousand random cases, all loaded in a batch, it would seem to me that even with consistent torque, some will be crimped more than others.

    Of course we have the same problem with any other crimp technique because, unless case length is absolutely uniform, the crimp depth will vary.

    For precision rifle, there is an arbor press for bullet seating that measures neck tension. But precision rifle is a whole different thing than loading dumpster quantities of pistol ammo.

    #5 F106 Fan, Sep 13, 2012
    Last edited: Sep 13, 2012
  6. If you are using the taper crimp in the seating die to remove the flare, then you are mildly taper crimping. So yes, always crimp your semiauto ammo ofr proper functioning. Leaving the flare or bell, even only 0.001" can cause feeding issues.
    There have been reams written about the uslessness of the LFCD. A poor solution to just about any problem your ammo may have. If you need a LFCD to get your ammo to work, then you need a reloading class not a LFCD.
    #6 fredj338, Sep 13, 2012
    Last edited: Sep 13, 2012
  7. Taper crimping IS deflaring. Simple as that. Only time your are actually bending the case inward is when you have the bullet seated short enough to bend it inward with out denting the bullet. Its pretty clear if you look at the Lyman reloading manual.
  8. Yes Steve, but it's not called a taper flare but a taper crimp. Come on guys, you are getting way off into the weeds.:upeyes:
  9. with minimum flare/expansion of the case mouth, all you need to do is bump the case mouth with a taper crimp die to straighten them out. Redding, RCBS, heck, even Lee make good crimp dies.
    No need for the FCD or some fancy crimp die.
    Sorting cases, ensuring consistent powder charges, straight line bullet seating will all have more affect on accuracy than the brand of crimp die you use.
  10. A roll crimp die would remove the flare just as well. Just saying. It's irrelevant if all you do is use minimal flare and the declare.
    #10 Colorado4Wheel, Sep 13, 2012
    Last edited: Sep 13, 2012
  11. SPIN2010

    SPIN2010 Searching ...

    Just an example.

    Quote: Throughout the rest of this discussion, bear in mind the fact that not all cartridges will require a crimp of any kind. For those cartridges which can be loaded without resorting to a crimp, we recommend omitting this step altogether.

    ... and to be fair. The article covers taking out the flare on a straight case as crimping. :dunno:
  12. I taper crimp all my 9mm to 0.375.
  13. Since no one else has mentioned it, I will. Too much crimp can be dangerous. Remember, the 9mm, 40, 45, and other straight walled rimless pistol cases headspace on the case mouth running into the step at the end of the chamber. If a case is crimped too much, it could wedge itself a bit past that step. This would drastically raise pressure, as the case would not release the bullet properly.

    This degree of overcrimping would be difficult with standard dies for the caliber. But it is possible if one gets overzealous. When setting up the seating/taper crimping die, look to see if the case mouth is getting deformed or shaved. If it is, that's way too much crimp. And NEVER NEVER roll crimp a straight walled rimless pistol cartridge for a semi-auto pistol. Roll crimping is for revolvers with rimmed cases, or rifle cartridges. This would be hard to do anyway unless one was using bullets with a groove or cannelure. Cast bullets have them. One could overcrimp a soft lead bullet, too, to the point of being dangerous.
  14. That seems like a lot as the SAAMI case mouth measurement is .380.
  15. I've been measuring factory and some of my reloads with different bullets... Is that SAAMI figure "nominal"? "maximum"? There is no time in the reloading process where .380 is achieved with my setup (except the temporary flare of course).
  16. The .3800" dimension is a 'reference'. There is no tolerance specified other than note about Body Diameter - 0.007".

    The .3800" also must be a MAX number because the chamber is spec'd at 0.3810" and there must be some clearance or the slightest puff of smoke will keep a round from chambering.

    The .3810" dimension is also a 'reference'. If it has a tolerance, it is +0.004".

    Notice that the 0.3800" and 0.3810" are specified to the nearest ten thousandth of an inch. The spec if very serious about these numbers to have spec'd them to 4 decimal places.

  17. Correct & I have done that. Still, it is correct to call it crimping because you are using a taper crimp die. Semantics maybe, but is what it is.:dunno: FWIW, I don'tthink I have ecer measured case mouth crimp. If you can see a crimp w/ a taper crimp, it's too much.
    #17 fredj338, Sep 14, 2012
    Last edited: Sep 14, 2012
  18. I just want people to understand that you don't actually bend the case inward.
    #18 Colorado4Wheel, Sep 14, 2012
    Last edited: Sep 14, 2012
  19. And if you over crimp you start sizing the bullet.
  20. Very true, why I always tell noobs to pull a bullet & see how it looks. You can also over crimp w/ a roll crimp, but it's harder to do.:wavey:

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