Earlier this year B&T announced the USW Grip Module for the Sig P320. The conversion is done simply by popping out the trigger group ( which is the serialized portion of the P320) out of the grip frame and into the B&T USW Grip Module.
The USW-320 measures with the stock closed only 1.7 inches with a length of pull of 14.17 inches.
The stock of the USW-320 is a right side folding stock and weighs 6.6 ounces empty.
The USW-320 was designed to convert the Sig P320 pistol ( fullsize or compact) into a PDW or a Universal Service Weapon Configuration.
The USW-320 is designed to be the same size as a standard service pistol but with a stock and the capability to reach out and engage targets north of 50 yards, essentially doubling the Sig P320 range capability.
The B&T USW-320 also uses P320 magazines.
One thing to note, you must first file a FORM 1 with BATFE to comply with the NFA title II restriction on short barreled rifles before configuring your title I Sig P320 into the USW-320 chasis.