Jonathan Ferguson, a weapons expert and Keeper of Firearms & Artillery at the Royal Armouries, breaks down the weaponry of Atomic Heart, including the KS-23 shotgun, the Kalash rifle, and the Fat Boy rocket launcher. Jonathan Ferguson, a weapons expert and Keeper of Firearms & Artillery at the Royal Armouries, breaks down the weaponry of Atomic Heart, including the KS-23 shotgun, the Kalash rifle, and the Fat Boy rocket launcher.