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40 cal v 10mm

Discussion in 'Ammunition' started by The Village Idiot, Aug 17, 2008.

  1. The Village Idiot

    The Village Idiot Shooting at the big range in heaven. 1952-2009 NES Member

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    This may have been covered before but..

    If 40 cal = 10.16mm and 10mm = 39.37 cal, what is the difference between the two and why do people seem to prefer the 10mm over the 40 caliber? Is it in the loading?

    Thanks,

    Ed
     
  2. Mike-Mike

    Mike-Mike Instructor Dealer

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    The length of the cartridge. It's like a .38 and .357 mag.

    They are the same caliber one just the ability to carry more powder and higher pressures.
     
  3. The Village Idiot

    The Village Idiot Shooting at the big range in heaven. 1952-2009 NES Member

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    Makes sense.

    Thanks,

    Ed
     
  4. jar

    jar NES Member

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    The 40 is a descendant of 10mm. The 10mm auto cartridge was adopted by the FBI after the 1986 Miami shootout. The FBI decided that the recoil of full power 10mm loads was too much for many agents, so they specified a reduced load. Smith and Wesson realized that with the FBI load they didn't need the full case capacity of 10mm. They created the 40 S&W to allow them to build pistols for the FBI loading on the same frame size as 9mm, and now the 40 is far more popular.
     
  5. M1911

    M1911 Moderator

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    The shorter .40 cartridge allows for a smaller grip circumference. 10mm allows for a more powerful load if desired.
     
  6. drgrant

    drgrant Moderator

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    It's all about the load. The bullets are typically the same, except for the 200 grainers, which typically are only found in 10mm Auto loadings. 10mm Auto has a longer
    case, usually thicker brass, and a large pistol primer for ignition.

    The key technical difference is that .40 S+W "roofs out" pretty quickly- there's literally not a whole hell of a lot of headroom in loading .40 S+W, especially with 180 grain bullets. In .40 S+W said bullet might be cruising around 1050 fps tops at pressure max. In 10mm auto that same bullet can be going well northward of 1200 FPS!!! [grin]

    Basically, think of .40 S+W as an intentionally crippled 10mm. It's not that it's a completely terrible cartridge, but it's WAY less versatile than 10mm Auto is, and the maximum
    power capability of the 10mm is easily an order or so of magnitude greater than .40 S+W.

    -Mike
     
    Last edited: Aug 17, 2008
  7. The Village Idiot

    The Village Idiot Shooting at the big range in heaven. 1952-2009 NES Member

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    I appreciate the answers to my questions. There is a wealth of knowledge to be tapped here on NES. A couple of goofy shits like myself, but a lot of knowledge.

    Thanks all,

    Ed
     
  8. vellnueve

    vellnueve Member

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    The bullet diameter is the same. The 40 S&W is just a shortened 10mm case.
     
  9. drgrant

    drgrant Moderator

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    True on the former, but not entirely so on the latter. The case head area of the 10mm has a slightly thicker web and it also takes a large pistol primer instead of a small one. Of course I'm being pedantic here, but this is one of the main differences between the two, and it also contributes overall to the difference in capability between the cartridges.

    -Mike
     
  10. vellnueve

    vellnueve Member

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    -1 for myself
     
  11. EddieCoyle

    EddieCoyle Consigliere Moderator

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    I've loaded light bullets in the 10mm to over 1500fps.

    The .40 S&W is dead to me. Dead.
     
  12. TonyDedo

    TonyDedo Member

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    Is there any compatibility between the two calibers, like there is between .38 special and .357 magnum (i.e. you can shoot .38 special from a .357 magnum revolver)?
     
    Last edited: Aug 31, 2008
  13. M1911

    M1911 Moderator

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    Yes, you can shoot .38 Special in a .357 Magnum revolver (but not the reverse). The same is true for .44 Special and .44 Magnum.
     
  14. TonyDedo

    TonyDedo Member

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    Sorry, my question was ambiguous. I was asking, does the 10mm and .40 S&W share the same compatibility that calibers like .38 special and .357 magnum do? Is there a gun chambered in 10mm that can shoot .40 S&W?

    I imagine in an automatic there would be some problem with chamber size and extraction, but it doesn't hurt to ask, I suppose.
     
    Last edited: Aug 27, 2008
  15. drgrant

    drgrant Moderator

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    S+W 610 series wheelgun will shoot both. IIRC with autos the springfield omega was the only one that could handle both at once without a barrel change, and that gun has basically gone into dodo bird land for support.

    -Mike
     
    Last edited: Aug 27, 2008
  16. Joe R.

    Joe R. Member

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    The platform is different except for the barrel ( caliber. ) The .40 Short and Weak uses the 9mm sized frames for their basis. The 10mm Auto would be closer to the .38 Super for frame size than .45, at least on the 1911 platforms. You couldn't fit a 10mm in a 40 S&W mag and the other way would leave a jump into the ramp/chamber + the round probably won't headspace well and would lead to accuracy problems.

    Joe R.
     
  17. Scrivener

    Scrivener Banned

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    Overbroad and inaccurate as stated.

    GLOCK
    "uses the 9mm sized frame for their [sic] basis [sic]." It does so by undercutting the chamber to fit the feedramp into the too-short frame, leading to the occasional, but spectacular, "Ka-Boom" for which .40 Glocks are notorious.

    1911's chambered in .40 (and they are legion) build on the standard .45 frame (which is why many .40 shooters "load long"). Smith & Wesson uses a larger frame for its .40 and .45 M&P's and Chief's Special pistols than it does for the 9mm versions of those models.

    Note also that the barrel is NOT the same for .40 and 10 mm. As the latter is longer, thus requiring a different chamber, it necessarily follows that each caliber requires its own barrel if the gun is an autoloader.
     
    Last edited: Aug 28, 2008
  18. CTSHOOTER

    CTSHOOTER New Member

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    [​IMG]

    .357 Sig, 10mm, .40 S&W
     
  19. KMM696

    KMM696 NES Member

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    Does the 357 Sig have the same Glock kBoom potential as the 40? Looks (by eyeball, anyway) to be roughly the same OAL & brass diameter as the 40.

    What's out there for MA available 10mm pistols these days, anyway? I see the occasional Glock 20 - anything new?
     
  20. Scrivener

    Scrivener Banned

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    The .357 SIG is essentially a .40 S&W necked down to take a 125 grain, 9mm bullet. The object of the exercise was to duplicate the .357 Magnum 125 JHP in an auto cartridge.
     

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