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. Fixed blade front and fixed notch rear sights, front-mounted hammer, "MARK I" marked on the left side, and a pair of smooth grips. With a hardwood MBA display case, ten dummy rounds of Gyrojet ammunition, and MBA news release.

Excellent, retaining 99% original black finish with limited handling marks. The left grip is also excellent with limited handling marks. The detached right grip is fair with a chip out of the top and a crack. Mechanically excellent. Case is fine with some storage and handling marks, wear on the lining, and a repair in the cartridge block and trigger block.