MBA Gyrojet
MB Associates (Mainhardt-Biehl Associates) · Pistol · Out Of Production · 1965
Also known as: MB Associates Gyrojet, MBA Gyrojet Mark I, Gyrojet Mark II, Microjet pistol, rocket pistol
Overview
The MBA Gyrojet is a family of unconventional firearms developed by MB Associates of San Ramon, California in the early 1960s by founders Robert Mainhardt and Arthur Biehl. Rather than firing a conventional bullet propelled by a chamber pressure spike, the Gyrojet fires miniature self-propelled rocket projectiles called 'Microjets' from a smoothbore launch tube. Each 13mm rocket round contained its own solid propellant, a primer struck by an inverted firing pin, and four small canted jet nozzles at its base that both expelled exhaust and spin-stabilised the projectile in flight. The pistol's launch process generated almost no felt recoil, virtually no muzzle blast, and produced no spent brass - but muzzle velocity at the launch tube was a sluggish ~30 m/s, only accelerating to roughly 380 m/s after travelling 6-9 metres downrange. This made the Gyrojet uniquely ineffective at close range, where the projectile carried little energy, while paradoxically becoming more dangerous further away. The aluminum-framed pistol weighed only 620 grams, fed from a 6-round integral magazine, and was offered briefly as a futuristic novelty alongside Gyrojet carbines and rifle-length 'Lancejet' variants. Severe accuracy problems, manufacturing inconsistencies (every rocket needed perfectly symmetric nozzles, which the production line could not reliably deliver), and the 1968 Gun Control Act's reclassification of the 13mm rounds as destructive devices effectively killed the product line by 1969.
Specifications
| Weight (empty) | 620 g (21.9 oz) |
| Overall Length | 300 mm (11.81") |
| Barrel Length | 127 mm (5.00") |
| Action Type | Blowback |
| Firing Mechanism | Single Action |
| Trigger Type | Single Stage |
| Magazine Capacity | 6 rounds |
| Magazine Type | Internal |
| Muzzle Velocity | 30 m/s (98 fps) |
| Effective Range | 50 m (55 yd) |
| Maximum Range | 1800 m (1968 yd) |
| Barrel Rifling | None |
| Number of Grooves | 0 |
| Frame Material | Aluminum |
| Slide Material | Aluminum |
| Barrel Material | Aluminum |
| Finish | Anodized |
Calibers
- 13mm Gyrojet · primary — also known as 13x50mm Gyrojet, 13mm rocket, Gyrojet Mark I
Features
- Firing modes: Semi Automatic
- Feed systems: Internal Single Stack Magazine
- Safety mechanisms: Manual Safety
- Features: Fires Self Propelled Rocket Projectiles, No Rifling Smoothbore Launch Tube, Spin Stabilized Via Canted Jet Nozzles, Minimal Recoil, No Chamber Pressure, Underwater Capable, Lightweight Aluminum Construction, Cartridge Does Not Eject No Brass
Variants
- Gyrojet Mark I Pistol (13mm) — Original
- Gyrojet Mark II Pistol (12mm) — Post Gca 1968
- Gyrojet Carbine — Long Arm
- Lancejet (rifle-length) — Long Range
Service history
Operators
- United States Military (limited Vietnam field trials) · adopted 1966
- Civilian novelty market · adopted 1965
Conflicts
- Vietnam War (1955-1975)
Production
Estimated total produced: 1,000 · Production years: 1965-1969
Total production of the 13mm Mark I pistol is estimated at roughly 1,000 units, with even smaller numbers of Mark II pistols, carbines, and Lancejet rifles. Surviving examples with original ammunition are sought-after collector items and museum pieces.
Origin
Country of origin: United States
Designer: Robert Mainhardt and Arthur Biehl
Discontinued: 1969
Notes
The Gyrojet's smoothbore launch tube means it is not technically a firearm under some legal definitions; the propellant burns inside the projectile after it has left the gun. Surviving 13mm Mark I pistols and unfired ammunition are now extremely valuable collectors' pieces, with intact original cartridges sometimes selling for hundreds of dollars per round. A few examples were carried by US officers in Vietnam as personal sidearms, but no formal military adoption ever occurred and field reports were uniformly negative.
Background
The Gyrojet has the unique distinction of being a James Bond gun: Sean Connery's Bond uses a Gyrojet pistol in the 1967 film You Only Live Twice, where it appears as a futuristic spy weapon supplied by Tiger Tanaka. Gyrojets also feature in the 1976 film Logan's Run as the iconic 'Sandman' guns, and a Gyrojet carbine appears in the original Battlestar Galactica. The brilliant theory and disastrous execution made the Gyrojet a textbook engineering cautionary tale - even MB Associates' own marketing literature struggled to disguise the fact that every customer's first shot was usually their last attempt to take the system seriously.