Originally Posted by SmithKid308
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 ?
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.