Description
U.S. .50-Caliber M3 Aircraft Machine-Gun Ejector Spring, P/N A7313885, Saco-Lowell, 1954
Item Overview
This original U.S. military ejector spring was made for the .50-caliber M3 basic aircraft machine gun. Its drawing and part number is A7313885. This listing includes one spring only. The original bulk-package label identified a quantity of 20 springs, but this product is not a package of 20. It is an internal gun component and is not part of an aircraft mount, cradle, or ammunition system.
Identification Details
The original package label provides the following military identification and contract information.
- Nomenclature: Spring, Ejector
- Part and drawing number: A7313885
- Weapon application: Gun, Machine, Cal. .50, M3, A/C Basic
- Manufacturer: Saco-Lowell Shops
- Manufacturing location: Biddeford, Maine
- Contract number: DA-19-020-ORD-775
- Apparent packing date: November 1954
- Original bulk-package quantity: 20 springs
- Quantity included with this listing: One ejector spring
Function in the M3 Machine Gun
The ejector spring fits in a recess in the extractor assembly, beneath the ejector. The extractor assembly is installed in the gun’s bolt group. The spring keeps pressure on the ejector as a fired cartridge case is removed and discharged from the receiver. Military manuals show that the ejector and spring could be positioned for either left-hand or right-hand ammunition feed. This small part was therefore important to the reliable operation of the gun.
About the M3 Aircraft Machine Gun
The M3 was a high-speed development of the Browning .50-caliber aircraft machine gun. It was an automatic, recoil-operated, air-cooled weapon that used disintegrating-link ammunition belts. The gun could be set up for left-hand or right-hand feed and was normally fired by an electric solenoid connected to the aircraft’s controls. Military specifications list a rate of fire from about 1,150 to 1,250 rounds per minute, commonly described as roughly 1,200 rounds per minute.
Weapon-System History
The M3 was developed during the final years of World War II to give American aircraft a faster-firing .50-caliber weapon. It kept the proven Browning operating system while increasing the rate of fire for high-speed air combat. The design became an important early Cold War aircraft gun and was installed in versions of the F-80 Shooting Star, F-82 Twin Mustang, F-84 Thunderjet, and F-86 Sabre. The number and placement of guns varied by aircraft and model.
History of Use
M3 aircraft guns saw important service during the Korean War. They were used for air-to-air combat and ground-attack missions by several types of U.S. jet and propeller-driven fighters. Their high firing rate helped place a large number of rounds on a target during the short firing time available at aircraft speeds. The November 1954 date on the package places this spare part just after the Korean War, when M3-equipped aircraft still required replacement parts for service, training, and reserve use.
Manufacturing and Historical Context
Saco-Lowell Shops produced this part in Biddeford, Maine, under U.S. military contract DA-19-020-ORD-775. The labeled bulk quantity of 20 shows how small replacement parts were packed and supplied to military maintenance organizations. Individually packaged or stored components helped armorers keep aircraft guns ready without replacing a complete bolt or extractor assembly.
Compatibility Notice
This spring is identified for the basic .50-caliber M3 aircraft machine gun. Compatibility should be confirmed by part number A7313885 and the applicable parts manual before use. No compatibility with the M2HB, other Browning variants, aircraft mounts, or unrelated weapon systems is claimed.
Collector and Restoration Value
This ejector spring is a useful example of an original 1950s military spare part. It is well suited for an inert M3 aircraft-gun display, museum restoration, technical study, or Cold War aviation collection. The part number, manufacturer, contract, and packing information also give it value as a record of U.S. military supply and maintenance practices.
Condition
This vintage surplus spring may show storage grease, finish wear, discoloration, light surface oxidation, or other signs of age and long-term storage. Markings, finish, and condition may vary between available examples. Original bulk packaging is not included unless specifically stated elsewhere in the listing.
Ideal For
This original component is suitable for historical collections, displays, and research involving American aircraft weapons.
- M3 and AN-M3 aircraft machine-gun displays
- Korean War aviation collections
- F-80, F-82, F-84, and F-86 research
- Military armorer and ordnance exhibits
- Aircraft-gun restoration references
- U.S. military contract-parts collections
Approx length 0.3", Approx width 0.25", Approx height 0.25", Approx weight 0.01 lbs.
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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