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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. When Colt Industries was contacted, they showed considerable interest in producing the weapon, but before committing to full production they insisted on a market survey to see if there was an adequate market for the gun. Colt demonstrated the weapon to a number of departments, and all who saw it were impressed with its compactness, volume of fire and reliability. However, the national recession at that time did not allow any adoption of the weapon and by 1971 the project was over.
The weapon was composed of an aluminum alloy receiver with steel inserts and was covered in an epoxy paint finish. The final version of the weapon was available in 4 variants. The first variant was a simplified one, with no special features. The second variant incorporated a barrel selector on the rotating striker on the hammer. This allowed the shooter to select any one of the eight barrels. This meant that the weapon could be loaded with a variety of ammunition and the shooter could select the most appropriate round for the given situation. The third variant contained a receptacle for a canister of tear gas between the barrels. Pressing the trigger on the foregrip allowed the shooter to spray the target with tear gas, giving him a non-lethal option. The final, fourth variant had both the barrel selector and the tear gas canister.