I recently blogged about RAA’s PDS pistol. This is the carbine version of the pistol.

The Piston Driven System Carbine utilizes a propriety bolt carrier that actuated by a piston. The return spring is located above the barrel, much like the Para Ordnance TTR rifle, rather than the rear buffer spring. This eliminates the need a buffer tube, allowing a folding stock. Unlike the Para TTR the PDS does not have a traditional AR-15 charging handle and instead has ambidextrous forward H&K-esque charging handles.

Gas block and charging handles