The new A-TAC Force DUO-SYS shotgun from Turkish manufacturer Khan Arms debuted at IDEF 2015 in Istanbul. The Khan DUO-SYS 12 gauge action allows the user to alternate between pump/action mode and semi-automatic mode, this is of most use to law enforcement who might be switching between various rounds, such as breaching rounds, that might not have the energy to cycle the action.
The shotgun has a full length fixed stock with a ergonomic pistol grip. A magazine extension is installed (although I don’t know the capacity). A door breaching-style muzzle brake is installed on the 20″ barrel along with a heat shield. It has an iron rear sight built into the picatinny rail on top of the receiver. Optics are a popular shotgun accessory in Turkey due to gun laws prohibiting rifle ownership.
These shotguns tend to be sold in the Middle East and Eastern Europe. I am not sure what they sell for.
Thanks to Lionel for the photos and information.