A product of the 1960s, the Mark I Gyrojet uses a 13mm 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. Adjustable blade front and fixed notch rear sights, front-mounted hammer, "MARK I/MODEL B" marked on the left side, and a pair of smooth grips. Includes a MBAssociates "Rocketeer" box.

Excellent, retaining 98% original black finish with a few light handling marks, and minimal high edge wear. Grips are also excellent with limited handling marks. Mechanically excellent. Box is very good with storage and handling marks and staining.