Description
U.S. Navy 20 mm Mk 7/Mk 12 Feed-Mechanism Cover Plate, P/N 1236046-B, NGF, November 1957
Item Overview
This vintage U.S. Navy cover plate was made for a 20 mm aircraft-gun feed system. The base drawing number 1236046 is officially cataloged as PLATE, COVER under NSN 1005-00-334-2891. Period Navy records strongly support its use in the Mk 7 pneumatic feed mechanism fitted to the Mk 12 aircraft cannon. This listing includes one cover plate only. It does not include a feeder, cannon, aircraft, mounting hardware, ammunition, or other parts.
Identification Details
The stamped and cataloged information identifies this as an original Cold War-era naval ordnance component.
- Nomenclature: Plate, Cover
- Drawing and part number: 1236046-B
- Cataloged base number: 1236046
- National Stock Number: 1005-00-334-2891
- Federal Supply Class: 1005, Guns through 30 mm
- Supported application: Mk 7 feed mechanism for the Mk 12 aircraft cannon
- Drawing revision: B
- Manufacturer marking: NGF, Naval Gun Factory
- Manufacturing location: Washington Navy Yard
- Packaging date: November 1957
- Quantity included: One cover plate
Function in the Mk 7 Feeder
Based on its shape and period feeder documentation, this part appears to be a bolted cover or guide plate in the Mk 7 cover-drive area. Its slots provide clearance for moving feed components while the plate helps close or guide part of the mechanism. The exact mounting face and installed direction remain unconfirmed because drawing 1236046 and the illustrated parts breakdown were not available for review.
About the Mk 7 Feed Mechanism
The Mk 7 was a pneumatic, piston-operated feeder mounted above the Mk 12 receiver. It pulled linked ammunition through the feeder, removed the belt links, and placed each cartridge where the moving breechblock could push it into the chamber. The feeder was externally powered and did not recoil with the gun. A June 1957 military specification for Mk 7 feeder sets identified major areas and parts such as the cover-drive assembly, ejectors, pawls, piston, and valve stem.
About the Mk 12 Aircraft Cannon
The Mk 12 was a 20 mm automatic cannon developed for U.S. Navy and Marine Corps aircraft during the early Cold War. It belonged to the Hispano-Suiza 404 family but was adapted for greater speed and improved aircraft service. The cannon used electric firing, a pneumatic charging and buffer system, and an externally powered feeder. Period Navy data lists a firing rate of about 1,000 to 1,100 rounds per minute. The long Mk 12 Mod 0 was intended mainly for fixed installations, while the shorter Mod 1 was often described as the turret-type version.
Weapon-System History
The Navy needed a fast-firing cannon that could attack aircraft and ground targets with more power than a rifle-caliber machine gun. The Mk 12 filled that role during the 1950s and remained important as guided missiles entered service. Variants of the cannon armed aircraft such as the FJ-4 Fury, F4D Skyray, F11F Tiger, F8U and F-8 Crusader, and A4D and A-4 Skyhawk. These installations depended on reliable feeders because even a small interruption in ammunition movement could stop the cannon.
History of Use
Mk 12 cannons served aboard carrier-based and land-based Navy and Marine aircraft. Pilots used them for air combat, strafing, close support, and attacks on light ground or water targets. A-4 Skyhawks and F-8 Crusaders carried the weapon during the Vietnam War, where cannon fire remained useful at close range and against targets that did not require larger ordnance. The system also served with foreign aircraft operators, including the Royal New Zealand Air Force on the A-4K Skyhawk.
Naval Gun Factory Background
The NGF marking identifies the Naval Gun Factory at the Washington Navy Yard. This facility was a major center for producing, repairing, and testing U.S. naval weapons and related equipment. The November 1957 packaging date places this plate during the early service and support period of the Mk 12 cannon system. The “B” suffix identifies a drawing revision and should not be confused with a cannon or feeder modification number.
Compatibility Notice
The cataloged identity of part 1236046 is well established, and the Mk 7/Mk 12 application is strongly supported by period documentation. However, buyers should compare the part number, dimensions, hole pattern, and required revision with their technical records before installation. This is a specialized feeder component and should not be treated as a universal 20 mm gun plate.
Collector and Restoration Value
This plate is a useful artifact for studying Cold War naval aviation, automatic-cannon feed systems, and Washington Navy Yard production. It may also support a properly documented static restoration or parts display involving a Mk 7 feeder or Mk 12 cannon. Its original part number, NGF marking, and dated packaging add research and display value.
Condition
This vintage military-surplus component may show storage grease, finish wear, scratches, stains, light oxidation, worn packaging, or other signs of age and handling. Markings, finish, packaging, and exact condition may vary between available examples.
Ideal For
This part is well suited for historical collections, research, and correctly identified display projects.
- U.S. Navy aviation-ordnance collections
- Mk 7 feeder and Mk 12 cannon research
- Cold War aircraft-gun displays
- Washington Navy Yard and NGF collections
- Military museum and archival exhibits
- Documented static restoration projects
Approx length 5.5", Approx width 5", Approx height 0.1", Approx weight 0.3lbs.
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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