iraiam For example 380 acp does not measure 380, nothing about it does. Its only a thousands but that also the difference betwen a many others. The 357 sig is not made from 40sw brass ether and as others noted it does not use a .357 bullet. Same .355 as a 9mm but even then with some bullet makers they do list a heavier jacket on the bullet for the "sig cartidge too.
If you try it there will not be enought neck left and the brass will be shorter than needed.
Thats the reason HE and YOU should go to a reloading site or wiki page to find out what HE wants to know.
PAX Your site looks to be general enought to be full of good basic info. Nice looking site.