MBA Gyrojet Carbine
MB Associates (Mainhardt-Biehl Associates) · Carbine · Out Of Production · 1966
Also known as: MB Associates Gyrojet Carbine, Gyrojet Mark I Model B Carbine, Gyrojet rocket carbine
Overview
The MBA Gyrojet Carbine is a rocket-firing carbine developed by MB Associates of San Ramon, California as a long-arm member of the Gyrojet family designed by Robert Mainhardt and Arthur Biehl. Like the Gyrojet pistol, it fires miniature self-propelled 13mm rocket projectiles from a smoothbore launch tube rather than a conventional bullet driven by chamber pressure; each round carries its own solid propellant and four canted jet nozzles that expel exhaust and spin-stabilise the projectile in flight. Built almost entirely of aluminum, the carbine loosely resembles an early AR-style rifle, with a full-length handguard, a fixed carry handle housing an adjustable rear sight, a high front sight, a contoured pistol grip and a shoulder stock. Its long barrel lets the rocket burn and accelerate for a greater portion of its powered flight before leaving the muzzle, which improved accuracy and downrange energy relative to the short pistol while retaining the system's near-zero recoil, minimal blast and lack of ejected brass. The round leaves the muzzle at a sluggish velocity of roughly 30 m/s and only accelerates to about 380 m/s several metres downrange once its fuel is expended. The carbine was made in very small numbers in the mid-to-late 1960s before persistent accuracy and reliability problems, high ammunition cost, and the 1968 Gun Control Act's reclassification of the 13mm rounds as destructive devices ended production.
Specifications
| Weight (empty) | 1400 g (49.4 oz) |
| Overall Length | 890 mm (35.04") |
| Barrel Length | 470 mm (18.50") |
| Action Type | Single Action |
| Firing Mechanism | Single Action |
| Trigger Type | Single Stage |
| Magazine Capacity | 6 rounds |
| Magazine Type | Internal |
| Muzzle Velocity | 30 m/s (98 fps) |
| Effective Range | 65 m (71 yd) |
| Maximum Range | 1800 m (1968 yd) |
| Barrel Rifling | None |
| Number of Grooves | 0 |
| Frame Material | Aluminum |
| Barrel Material | Aluminum |
| Stock 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, Long Barrel Extends Rocket Acceleration, Carry Handle With Adjustable Rear Sight, Lightweight Aluminum Construction, Cartridge Does Not Eject No Brass
Base model
Service history
Operators
- Civilian collector and novelty market · adopted 1966
Production
Production years: 1966-1969
Gyrojet carbines were produced only in very small quantities during the late 1960s; total long-arm production across carbine and Lancejet variants is believed to be at most a few hundred units before MB Associates abandoned the line.
Origin
Country of origin: United States
Designer: Robert Mainhardt and Arthur Biehl
Discontinued: 1969
Notes
Only a few hundred Gyrojet long arms of all types were built, and surviving carbines are rare collector pieces. Because the propellant burns inside the projectile after it leaves the smoothbore tube, the Gyrojet occupies an odd legal and technical niche between firearm and rocket launcher. Specification figures for the carbine are approximate; weight and overall length are estimates based on surviving examples and the roughly 18.5-inch barrel.
Background
The Gyrojet pistol and carbine featured prominently in the 1967 James Bond film You Only Live Twice, demonstrated by Q and used by Tiger Tanaka's ninja commandos, cementing the weapon's brief pop-culture life as a futuristic rocket gun. Conceived as the shoulder-fired counterpart to the Gyrojet pistol, the carbine was intended to leverage its longer barrel to cure the pistol's dismal accuracy, but the underlying problem - production rockets whose nozzles were never perfectly symmetric - meant the longer sight radius could only do so much for a projectile that steered itself off course.