Today I'm at SIG Sauer Parts (soon to be ModGuns) to play around with assembling a SIG 320. I've always been interested in stocked pistols, and so I'm going to take this opportunity to put together a USW (Universal Service Weapon). This originated as a complete pistol made by B&T (based on the CZ75) with an integrated folding stock and Aimpoint Nano optic. B&T decided to also make stocked chassis units for Glock and SIG pistols, and so the SIG model is what I'll do doing today. The modular design of the SIG 320 should make this a fun and pretty simple process...