The SIG SAUER P320 (FULL/M17) OWB Covert Kydex Holster has been one of the purchases I've ever made. It fits the weapon like a glove and is extremely comfortable to wear. It's streamlined design is not only practical and fully effective for carrying/drawing the weapon, but it is also solid from an aesthetics perspective as well. You'd do no better than this holster for your full size P320.
