[marktwain]

It is the .357 Sig caliber, designed to give .357 magnum performance out of a 9mm sized auto-pistol.

http://www.greent.com/40Page/ammo/357/357SIG-advoc.htm

[Wonder Warthog]

".357 Sig"

Thanks for the info. I have heard of the 357 Sig in passing, but my experience with it (and study thereof) is zero.