Whilst Magpul came out with the first prototype of a folding gun and developing it with Zev Technologies, B&T are the first to commercialise one in the real steel market with the B&T BWC. The Firearm Blog get to try out a unit and here is their take... "In this episode of TFBTV, James Reeves visits B&T in Switzerland to see their take on the folding carbine, the B&T BWC (“Because We Can”). The BWC is a 9mm folding SMG/PCC that uses a SIG P320 fire control unit or “FCU” meaning that the BWC itself is not a firearm, but a frame or chassis. This means that this folding pistol chassis is unregulated – a mere accessory. A SIG P320 owner can buy this chassis like any other unregulated accessory because it does not come as a complete firearm. Once you purchase it, you need only insert a SIG P320 FCU and slide/barrel upper, and you have a complete folding carbine."