S&W M&P 40 cal - 357 SIG

[GotGuns]

I just bought the S&W M&P 40 cal compact. Love it.
I heard all you need to do is change the barrel and you can shoot
357 rounds? The mag states 40/357 but can that be true change the barrel and shoot a different cal round? Does anyone know for sure??

Rob

 

[Mikey]

Sure is! If you can find a .357 Sig barrel.

 

[Jose]

The mag states 40/357 but can that be true change the barrel and shoot a different cal round?

Yes. It is true because the 357 Sig is formed using a case that has the same exact case head dimensions as the 40 S&W. The 357 Sig is basically a 40 S&W case necked down to .355" (9 mm). Since the head size of the 357 Sig and 40 S&W is the same, the mags and slides are interchangeable. You just need a different barrel to accomodate the differences from the shoulder forward.