Complete your U.S. aircraft cannon restoration with a scarce original internal component using this New Old Stock 20mm M39 Tube Latch Plunger. This is an authentic U.S. military part for the M39-series 20mm revolver cannon, preserved as unissued old stock and identified by Part Number 8401772 and FSN 1005-840-1772. For serious restorers, armorers, and collectors, this is exactly the kind of small but critical detail part that is often missing from surviving guns and far harder to replace than the major assemblies.

The M39 was one of the most important U.S. aircraft cannons of the Cold War era. Developed from postwar revolver-cannon concepts and standardized in the 1950s, the M39 family became a well-known 20mm aircraft gun used in major U.S. combat aircraft including the F-86, F-100, F-101, and B-57. Its compact revolver design gave American aircraft a high-rate, hard-hitting internal cannon at a time when aircraft armament was rapidly evolving from machine guns to heavier automatic cannon systems.

This Tube Latch Plunger belongs to the tube/barrel latch system of the M39 family. As the nomenclature suggests, it is part of the mechanism that works with the latch components to secure the gun tube assembly properly in place. On a restoration, these are the kinds of parts that matter. A major component may make the display look complete, but the smaller internal latch and lock parts are what preserve the gun’s true mechanical identity.

That is what makes this piece especially desirable. It is not a generic spring or pin. It is a named, cataloged M39 component tied directly to the tube latch assembly of one of the most recognizable American aircraft cannons of the 1950s and 1960s.

Because this example is new old stock, it offers a major advantage over worn service take-off parts. It was manufactured for military use but remained unissued, making it ideal for collectors and restorers who want original U.S. production rather than a used, damaged, or improvised substitute.

This part is an excellent fit for:

M39, M39A1, and related M39-series cannon restorations
Cold War aircraft armament collections
Museum and educational displays focused on U.S. aircraft gun systems
Spare parts inventories for original 20mm revolver cannon projects
Technical reference collections where correct, identified internal parts matter

Approx length 2", Approx width 1", Approx height 1", Approx weight .2lbs.

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.

Please visit our page about order lead times here: Order Lead Times