This new old stock 20mm Mk12 Barrel Clamp Nut is an original U.S. military surplus component used to secure the barrel assembly on the Mk12 aircraft autocannon. Identified by part numbers 7771581 and 829469 and National Stock Number (NSN) 1005-00-433-2803, this essential threaded fastener ensured the proper alignment and stability of the Mk12’s high-velocity 20mm barrel during sustained automatic fire.

The Mk12 cannon was widely fielded by the U.S. Navy and Marine Corps during the Cold War era, notably mounted on jet aircraft such as the F-8 Crusader and A-4 Skyhawk. A direct evolution of the Hispano-Suiza HS.404 lineage, the Mk12 fired 20x110mm navy ammunition and offered an increased rate of fire and reliability over its predecessors.

Product Specifications:

Condition: New Old Stock (NOS)
Part Numbers: 7771581 / 829469
NSN: 1005-00-433-2803
Compatibility: 20mm Mk12 aircraft autocannon
Function: Barrel securing

Historical Significance:

The Mk12 cannon played a central role in U.S. naval aviation firepower from the 1950s through Vietnam, offering superior anti-aircraft and ground support capability. The clamp nut ensured safe and effective operation of the weapon system, making it a critical part for restorers, collectors, and aviation historians.

Ideal For:

Mk12 cannon restoration projects
Military surplus collectors
Naval aviation museums and static display teams
Cold War-era aircraft armament reference collections

Approx length .5", Approx width .5", Approx height .3", Approx weight .1lbs.

Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item's general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.

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