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I'm confused .40 or 10mm

Discussion in 'Handguns: Autoloaders' started by Surplus nut, Feb 10, 2010.

  1. Surplus nut

    Surplus nut Member

    Ok, I know I'm going to catch a lot of flack for this one. I have been a collector and shooter for quite some time(surplus is what I stick to mostly), but seem to be confused. Is there a difference between 10mm and .40 cal? I thought they were the same, but know have some doubt.

    I am very interested in getting a nice handgun, preferably a sig. I have been trying to research a little. I was hoping to cash in on the sig's that you can get the .40 and .357 sig barrels for the same gun. I figure that would be the most practicle. I am also confused because I keep finding Sigs I like, but they seem to have a polymer frame. I only want to get a metal frame I think. Does anyone know what model Sig would be best?

    Thanks for any advice in advance.
  2. oasis618

    oasis618 Well-Known Member

    The .40 is a shorter cased version of the 10mm. 10mm is the REAL .40...if that makes any sense.
  3. Demitrios

    Demitrios Well-Known Member

    Here's the thing 10mm has a longer case than .40 S&W, in fact it came out before the 40. Depending on the gun it can be very dificult to upgrade from the 40 to the 10mm, however it is almost always (from my experience which. . . take it or leave it) to downgrade from 10mm to 40. or .357. Generally all you need is a new barrel, recoil spring and magazines. As far as Sig goes I know of only one model you can switch around like that a Stainless Sig P220.
  4. LeontheProfessional

    LeontheProfessional Well-Known Member

    It is like the difference between 7.62X51 and 7.62x39. 10mm is a good bit more powerful than the .40s&w. 10mm also costs a good bit more.
  5. hso

    hso Moderator Staff Member

    10mm Bullet weight/type Velocity Energy
    135 gr (8.7 g) Nosler JHP 1,600 ft/s (490 m/s) 767 ft·lbf (1,040 J)
    155 gr (10.0 g) Gold Dot HP 1,475 ft/s (450 m/s) 750 ft·lbf (1,020 J)
    165 gr (10.7 g) Golden Saber HP 1,425 ft/s (434 m/s) 744 ft·lbf (1,009 J)
    180 gr (12 g) Hornady XTP 1,350 ft/s (410 m/s) 728 ft·lbf (987 J)
    200 gr (13 g) WFNGC 1,300 ft/s (400 m/s) 750 ft·lbf (1,020 J)

    .40 Bullet weight/type Velocity Energy
    135 gr (8.7 g) Federal Premium JHP Low Recoil 1,190 ft/s (360 m/s) 424 ft·lbf (575 J)
    155 gr (10.0 g) Speer Gold Dot JHP 1,175 ft/s (358 m/s) 475 ft·lbf (644 J)
    165 gr (10.7 g) Speer Gold Dot JHP 1,150 ft/s (350 m/s) 484 ft·lbf (656 J)
    180 gr (12 g) Speer Gold Dot JHP 985 ft/s (300 m/s) 400 ft·lbf (540 J)
    200 gr (13 g) Double Tap Hornady XTP JHP 1,050 ft/s (320 m/s) 490 ft·lbf (660 J)

    As said, the .40 was the lower energy development in the US in response to the original 10mm. An anemic version of the 10mm
  6. Nick5182

    Nick5182 Well-Known Member

    The bullet diameter for both .40 cal and 10mm is .400". The FBI wanted a new cartridge to outperform the 9mm after the FBI shootout (in Florida I believe), and the 10mm was born, however the 10mm is a VERY hot round, and a lot of the agents couldn't handle the recoil and had hard times qualifying on the range, so the case was shortened to what is the .40S&W to be a powerful yet more controllable round. And I'm not an expert on this and hope my information is accurate.
  7. loadedround

    loadedround Well-Known Member

    To attempt to answer your question; think 38 special vs 357 mag, it's a similar situation betwen the 10mm and rhe 40 S&W rounds. The 10 mm Auto cartridge was a proprietary cartridge developed for the ill fated Bren Ten semi auto pistol. Shortly after this cartridge started to catch on, since it was a semi auto round with performance close to the 41 Rem Mag and when Colt chambered their 1911 for this cartridge as the 10 mm Delta Elite it became rather popular back in the 80's . Well the FBI liked the this cartridge, adapted it and Smith and Wesson came out with several semi autos for it. Unfortuantely women and men with small hands had difficulty handling this powerful round in the large framed semi auto's. Therefore S&W and Winchester developed a cartridge less powerful and that could be used on the small 9mm semi auto frame instead of the larger 10mm frame. While both cartridges use the same .400" diameter bullet, the cases are not interchangeable. The 10 mm case is longer and thicker, and uses large pistol primers, the 40 S&W is shorter, less powerful, and uses small pistol primers. However you may reload both on 10 mm dies since the case O.D. is the same. The 40 S&W is extremly popular with LE people today the 10 mm round has faded out and has become almost a cult cartridge even though several companies still chamber their pistols for the 10mm, namely Colt and Glock plus a few others. The 10mm round is an excellent cartridge and one of my favorites. :)
  8. rcmodel

    rcmodel Member in memoriam

    The obvious differance beside power is:
    The .40 S&W is short enough to fit in 9mm frame/magazine size guns. (1.135" Max OAL)

    The 10mm is enough longer to require a .45 ACP frame/magazine size. (1.260" Max OAL)

    That makes the 10mm better suited for people with bigger hands.

    The .40 S&W better suited for unisex police forces, etc.

  9. W.E.G.

    W.E.G. Well-Known Member


    HUGE difference.

    You can hardly find 10mm ammo anywhwere, and when you can, its usually PREMIUM ammo at sky-high prices.

    10mm makes no sense at all unless you are a handloader, or if you almost never shoot.

    By comparison, .40 S&W is widely available, and can be had for only about 30% more than the cost of comparable-quality 9mm ammo.
  10. KBintheSLC

    KBintheSLC Well-Known Member

    Yes... there is a difference. The 10mm in its full-power loading beats the .40 in both bullet weight and velocity. Does this power difference matter against a 2-legged predator? Who knows. But it makes a great woods load for bigger beasts. Here is some testing that compares the two. The .40 is shown towards the bottom of the article.


    10mm is a great load, and if you buy a Glock 20/29 you can fire cheaper .40 with a simple barrel swap.
  11. Zerodefect

    Zerodefect Well-Known Member

    Deos SIG even make a 10mm.

    The Glock 20 is the mother of all that is evil! Love that gun, but it's big.
  12. gandog56

    gandog56 Well-Known Member

    Yep, 10 mm handgun owners claim the "S&W" in .40 S&W stands for "Short and Weak". But they do shoot identical projectiles, just 10mm a lot faster.
  13. gandog56

    gandog56 Well-Known Member

    I've seen a SIG converted to 10mm on Sigforums.
  14. SNoB

    SNoB Active Member

    An interesting article on Wikipedia about the history of the .40 S&W's history can be found here.
  15. wrs840

    wrs840 Well-Known Member

    That really says it all. Very worth reading. FWIW, I like .40s...

  16. The Lone Haranguer

    The Lone Haranguer Well-Known Member

    Both use a .400" caliber bullet. (Technically, neither are a true 10mm caliber, which is .394". :neener:) The .40 can fit into a medium- or even small-frame pistol, being the same overall length as the 9mm Luger. The 10mm Auto, because of its length and original full power loading, generally needs a large-frame pistol. Even the compact Glock 29 is very thick and "chunky." To complicate matters further, the 10mm is offered in a full power and medium velocity load, the latter of which virtually duplicates the .40 in power, and some .40 loads are pretty hot, approaching the full power 10mm. :confused:
  17. makarovnik

    makarovnik Well-Known Member

    Just remember this: Get the 10mm!
  18. earlthegoat2

    earlthegoat2 Well-Known Member

    40 S&W=10mm Kurtz
  19. IdahoLT1

    IdahoLT1 Well-Known Member

    In terms of power, a bullet fired from a 10mm will as much energy at 100yds as a .45acp does at the barrel.
  20. Jed Carter

    Jed Carter Well-Known Member

    Only 2 SIG pistols to really choose from IMHO P229 and my favorite the SIG P226 .40S&W / .357SIG. No tupperware guns all metal. I recommend the SIG night sights and skip the rail if you can for no other reason than I don't like rails on pistols, make a good ugly SIG look uglier. I have 5 SIGs none polymer, Glock, H&K and FNH for plastic, again just an opinion. Get a P226 if it's not for carry or the versatile P229 if you intend to. Lots of info on the referenced calibers but none on the choices of firearms, P250, P2022 both polymer frame, P226 is perhaps the best pure weapon ever made. Get one in .40 and a replacement barrel in .357SIG for around $180.
    Last edited: Feb 11, 2010

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