A product of the 1960s, the Mark I Gyrojet uses a miniature solid fuel rocket in place of a standard cartridge. As the rocket does not need a solid chamber or extractor equipment, the entire pistol can be greatly simplified and made from lightweight materials. Fixed blade front and notch rear sights, a sliding magazine cover, front-mounted hammer, model, caliber and serial number markings on the left side, and a pair of smooth grips.

Excellent overall, retains 95% original black finish with a few scattered light handling marks and some light edge wear on the bottom forward frame and grip straps, and some scattered visible light scratches on the grips. Mechanically excellent.