.357 sig

Discussion in 'Semi-Auto Handguns' started by SmithKid308, Sep 25, 2011.

  1. SmithKid308

    SmithKid308 New Member

    I don't rember where I heard it but someone told me a .357 sig could shot a 9mm and .40 or a .45 not sure can anyone confirm this ?
  2. wjkuleck

    wjkuleck Lifetime Supporting Member Lifetime Supporter

    No, no and no.

    The .357 SIG is the .40 S&W necked down to accept a 9mm bullet. Therefore, the slide, extractor and ejector are the same as .40 S&W (and 10mm, for that matter). However, if you were to attempt to fire a .40 down the 9mm bore of the .357 SIG, were the round to chamber and fire you would destroy the pistol.

    The .45 ACP won't feed (it needs a .45 slide) nor chamber. The 9x19 Parabellum (Luger) won't feed properly, is way too small for the chamber diameter and just flat out won't work.

    I'm building a .357 SIG complete slide assembly to install on a LW .38 Super Commander, but the point is that you need a whole slide assembly, with barrel, for the conversion.



  3. Quentin

    Quentin New Member

    Walt is 100% correct as usual. However as he pointed out the 40S&W and 357Sig are very similar so all that would be necessary is to change the barrel on many pistols. (Assuming a barrel is available.)

    Glock for one, you can interchange 40S&W and 357Sig barrels and nothing else - you even use the same magazines. Only caveat is the barrels should be the same length so they fit that form factor pistol. There also are aftermarket barrels that allow you to convert a Glock 40 or 357 to 9mm but you really should change the extractor and maybe RSA too - and get 9mm mags.

    I've been tempted to get a 357Sig barrel for my G22 since it's pretty painless but honestly don't see much advantage and 40S&W ammo is a lot cheaper.
    Really the best solution is buy the caliber you think works best for you. And then if you need another, buy another gun.
  4. sweeper22

    sweeper22 New Member

    You're going to need to do at least a barrel swap. How elaborate/expensive the conversion ends up being depends almost entirely on the model of pistol in question.

    Glock is easily the most affordable to convert, but most guns that support 357sig are 100% interchangeable with 40sw nothing more than an extra barrel...because the bulk of the casing is identical. If you want to convert either of these to 9mm, you'll likley want a true "conversion" barrel that specifies calibers (ie: 40-9). Were you to simply buy any aftermarket 9mm barrel, the barrel/chamber/firing pin may not line up so well.