During its Homeland War, Croatia manufactured a wide variety of ad-hoc firearms including a number of anti-material rifles. The RT-20 was the largest of these, and its development began with the discovery of a stash of Yugoslav M55 anti-aircraft cannon barrels chambered for 20mm Hispano in a warehouse. These barrels were cut down, fitted with single-shot bolt actions, bipods, and bullpup stock assemblies and became the RT-20s. The most unusual element of the design is the use of gas vents about halfway down the barrel which open into a hollow tube which vents over the shooter's shoulder. This creates a gas exhaust jet upon firing to help counteract recoil (and also reducing the muzzle velocity by about 25%). The recoil from firing is still pretty brutal, but the guns can be used - and were during the war for Croatia's independence. A few remain in Croatian police inventory today...

A big thanks to the Croatian Police Museum (Muzej Policije) in Zagreb for giving me access to film this rare piece for you! Check them out at: https://muzej-policije.gov.hr