Re: s&w question
The .357 Sig will run thru any mag designed for the .40 S&W, and more reliably, to boot!
Obviously, the barrel will be changed, and likely a different recoil spring (20#?) will be required.
About the challenge level of tuning a .22 conversion unit, at about the same price.
Since you are talking 10mm, the Sig is a shorter round, which may require the use of either .40 S&W mags, or a modified follower, in the 10mm mags, with a spacer at the rear of the body; try a mag for the '40' series, full sized Smiths (4003-4006, etc) , comparing the length to your 10mm mag. Some of the 40's are shorter grip length, and these mags will not work, but the 40 series guns, with a full length grip, ought to interchange, and you would still have a functional 10 mm pistol, re-assembled !
Don't start no s**t and there won't be none, Terry