Colt Defender Mark I was an American 8-barrel shotgun intended for law enforcement or military use, completed in 1967. The shotgun had a semi-automatic like fire without the complexity of being a semi-automatic weapon. Each barrel was chambered for the 20 gauge 3 inch magnum shell. The barrels were joined together around a central axis with a pistol grip double action revolver mechanism and a second forward pistol grip for instinctive shooting. The shotgun was extremely simple to operate and very robust. The designer, Robert Hillberg, thoroughly tested the weapon before seeking out a manufacturer. The design proved to be so correct, that only a couple of minor changes were made for manufacturing.[citation needed] When Colt Industries was contacted, they showed considerable interest in prod