20mm Oerlikon Dummy Round

Inert 20mm Dummy Round for the 20x110mm Oerlikon Cannon

Item Overview

This inert 20mm dummy round represents a complete 20x110mm Oerlikon fixed cartridge. It was made to copy the size and general form of service ammunition without functioning as a live round. Dummy cartridges allowed military personnel to practice safe ammunition handling and learn how the complete cartridge worked with the gun and its magazine. This example is intended for collecting, historical study, museum display, and educational use. It is inert and is not intended to be fired.

Identification and Features

The 20x110mm Oerlikon cartridge is also commonly identified as the 20x110mm RB. The letters “RB” mean rebated rim, referring to the reduced-diameter extractor lip at the base of the cartridge case. U.S. Navy manuals used this feature to help distinguish Oerlikon ammunition from the separate 20x110mm Hispano-Suiza cartridge family. Exact markings, materials, paint, manufacturing dates, and construction details may vary among the dummy rounds covered by this listing.

• Item type: Complete dummy or drill cartridge
• Caliber: 20mm
• Cartridge family: 20x110mm Oerlikon
• Alternative designation: 20x110mm RB
• Original purpose: Ammunition handling and weapon-system training
• Ammunition form: Fixed cartridge
• Associated weapon: 20mm Oerlikon automatic cannon
• U.S. Navy applications: 20mm Oerlikon Guns Marks 2, 3, and 4
• Offered condition: Inert and non-firing
• Included: One inert 20mm dummy round

Dummy Versus Practice Ammunition

A dummy or drill round is different from practice ammunition intended for live firing. Wartime Navy references identified the Oerlikon drill projectile as empty, while separate blind-loaded practice cartridges could contain a live primer, propellant charge, or working tracer. A true dummy round was used for non-firing instruction and equipment drills. This example is offered as an inert collector’s item and should not be placed in or used with a functioning weapon.

Original Training Function

Dummy cartridges helped crews learn ammunition recognition, handling, magazine loading, unloading, feeding, chambering, extraction, and equipment checks without using service ammunition. They were especially useful when new sailors and gun crews were learning the operation of the Oerlikon cannon and its removable drum magazine. Dummy ammunition also allowed instructors to repeat drills aboard ships, at gunnery schools, and in maintenance areas. The exact training role of this individual example is not documented.

Cartridge and Weapon Application

The Oerlikon used fixed ammunition, meaning the projectile and cartridge case formed one complete unit for loading. Wartime naval guns normally received their ammunition from a removable spiral drum mounted above the receiver. The rebated case head was designed to work with the Oerlikon operating and extraction system. Although the Oerlikon and Hispano-Suiza cartridges both used 20mm projectiles and cases about 110mm long, they were separate ammunition families and were not interchangeable.

Weapon System History

The Oerlikon cannon developed from the German Becker automatic cannon created during World War I. The design passed through the Swiss firm SEMAG before Oerlikon continued its development during the 1920s and 1930s. The more powerful 20x110mm rebated-rim cartridge helped make the gun suitable for antiaircraft and naval defense. The U.S. Navy selected the improved Oerlikon before entering World War II and placed it into American production. Its air-cooled action, removable drum, simple pedestal mount, and manually controlled aiming system allowed the gun to be installed on many types of ships.

History of Use

During World War II, the 20mm Oerlikon became one of the most widely used close-range antiaircraft weapons in Allied naval service. It appeared on aircraft carriers, battleships, cruisers, destroyers, submarines, patrol craft, landing vessels, auxiliary ships, and armed merchant vessels. Crews used it against low-flying aircraft and other close targets in the Atlantic, Mediterranean, and Pacific theaters. It gave ships more short-range firepower than the heavy machine guns it often replaced. Later in the war, heavier 40mm guns became more important against large aircraft and kamikaze attacks, but the Oerlikon remained a familiar part of shipboard defense. Dummy cartridges supported this service by helping crews practice before handling live ammunition.

Historical Significance

This dummy round represents both the ammunition system and the training work behind one of the best-known naval guns of World War II. A gun crew needed more than a cannon and live ammunition; it also needed safe training tools that allowed each sailor to learn his assigned task. A complete inert cartridge clearly shows the size, shape, and rebated case-head design of Oerlikon ammunition while remaining suitable for display. No specific wartime date, manufacturer, cartridge Mark, or unit history is claimed for this example unless shown by its markings.

Condition

This is an inert surplus display round. It may show scratches, dents, worn paint, corrosion, oxidation, discoloration, tool marks, loose components, or other signs of age, storage, and training use. Cartridge-case material, projectile style, finish, markings, and internal dummy construction may vary. Because dummy rounds may be empty or fitted with inert material to copy service weight, the actual weight may also vary. This listing includes one inert 20mm dummy round only. The Oerlikon cannon, magazine, ammunition container, and other accessories are not included unless specifically stated.

Ideal For

This inert cartridge is well suited for collections and displays covering naval weapons, military training equipment, automatic cannon ammunition, and World War II history. Its complete-round profile makes it easy to recognize and display beside related Oerlikon cases, projectiles, magazines, manuals, or ship models.

• 20mm ammunition collections
• 20x110mm Oerlikon displays
• World War II naval exhibits
• Military training-aid collections
• Inert ordnance displays
• Museums and educational programs
• Veterans’ organizations and military-history rooms

Approx length 7.18", Approx width .83", Approx Approx height .83", Approx weight .53 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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