Need Help

Discussion in 'The Ammo & Reloading Forum' started by Sherrer1*, Jul 11, 2012.

  1. Sherrer1*

    Sherrer1* Member

    Joined:
    May 24, 2012
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    Location:
    Selma Alabama
    Im new to reloading for my pistol. My question is do I need a die set with a rolling crimp or a tapper crimp for reloading 40 s&w. Using a single stage press for now but do plan on moving to a progressive soon.
  2. gary0529

    gary0529 Member

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    Apr 15, 2007
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    Location:
    Northwestern Va.
    You will use a taper crimp--I doubt you can purchase a roll crimp in the seating die-the die makers have fixed this conundrum for you.

    Usually semi-auto cases that headspace on the mouth of the case use a taper crimp.

    Not to sound chippy but get a good reloading book or 3 and read, read read and don't take everything on the web as gospel until you have some experience under your belt and/or a very experienced mentor to help you.

    Gary
  3. howlnmad

    howlnmad Well-Known Member

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    :yeahthat: And stick with bottom end loads for the time being until you get a bit more proficient. And ask lots of questions.
  4. gdmoody

    gdmoody Moderator Supporting Member

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    I used a LEE single stage press for about 30 years before I got a progressive. A good single stage will last a lifetime, I still use that LEE for some of my loading. I agree with howlnmad about sticking with the lower end loads to start with.
  5. aa1911

    aa1911 Active Member

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    .40 like most rimless straightwall pistol headspaces off of the mouth; .423" is what the case mouth should be (diameter). Loading a bunch today. Case length is .850
  6. steve4102

    steve4102 Former Guest

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    In a semi-auto cartridge like the 40 S&W the term "Crimp" can be a bit confusing. The taper "crimp" for the 40 S&W as well as other rounds that headspace of the case mount is really not a "crimp". It is applied only to remove the flare(plus a thou or two) that was applied with the expander die prior to seating the bullet. You do not "crimp" the case mouth into the bullet, you apply just enough crimp to remove the flare, plus maybe a thou or two. Should hardly be noticeable to the naked eye.
  7. LDBennett

    LDBennett Well-Known Member

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    Sherrer1*:

    Most revolver cartridges have a protruding rim that sticks out beyond the body of the cartridge. The rim is what holds the cartridge from the blow of the firing pin.

    Semi-auto handgun cartridges have no protruding rim. There is a rim but it is usually the same diameter as the case body. The grove that makes that rim is there for the extractor to grab in extraction of the case after firing. The lack of a rim is done to aid feeding from a magazine. Semi-auto cases need some way of resisting the blow of the firing pin. The chamber of the barrel has a tiny ledge that the cartridge case mouth seats against to resist the blow of the firing pin. But what does this have to do with "crimps".

    Revolver cartridges can use a rolled over edge on the mouth of the case, called a crimp, to retain the bullet in the cartridge. Semi-autos need the mouth of the case straight so it will hit the ledge in the chamber. They use a taper crimp which leaves the case month straight but only ever so slightly pushed against the bullet. The difference in size of the bullet and the mouth of the case, as created by the reloading dies, creates what is called neck tension that retains the bullet in the case. The taper crimp is done to eliminate the belling done to aid bullet seating during reloading and to lightly push into the bullet.

    Hope that explains the why of crimps.

    LDBennett
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