Historical Significance:
In May 1940, shortly before the fall of France, Oerlikon engineer and representative Antoine Gazda arrived in America with manufacturing drawings of the 20-mm gun. His intention was to establish U.S. production of the Swiss weapon for the British Admiralty. Soon, the British Purchasing Commission began negotiating with the subsidiary America Oerlikon Gazda Corporation to manufacture 2,000 of the guns in its Rhode Island plant, but it could not get permission from the American government unless one of the U.S. armed services adopted the weapon.
The Admiralty quickly launched a campaign to convince the U.S. Navy to accept the 20-mm. Captain William H. P. “Spike” Blandy, the officer in charge of expediting antiaircraft gun production within the Navy’s Bureau of Ordnance (BuOrd), arranged for firing tests at the naval proving ground at Dahlgren, Virginia. All observers were favorably impressed with the gun, which then boasted a rate of fire of 450 rounds a minute, had an easily replaceable barrel, and was so robust that stoppages due to changes in elevation, cold weather, or rain were unlikely. Blandy, who even fired the gun himself, recommended its acceptance to the chief of the Bureau of Ordnance, Rear Admiral William Furlong. On 8 November, Arthur Purvis of the British Purchasing Commission wrote to Secretary of the Navy Frank Knox, urging him to adopt the Oerlikon as a standard weapon, and the next day Furlong approved its acceptance.
It took six months of bureaucratic haggling between the Navy, U.S. government, and the British Purchasing Commission before BuOrd could issue a contract to America Oerlikon Gazda under the Lend-Lease Act for 2,500 gun assemblies, 2,000 of which were slated for the British. The Hudson Motor Car Company and the Pontiac Motor Division of General Motors were also brought into the manufacturing picture.
The air-cooled 20-mm Oerlikon had some unusual features not found in other automatic weapons, including an open breechblock and a spring-recoil/counter-recoil system. It fired a 0.3-pound explosive shell supplied from a detachable magazine that held 60 rounds; expending all of them took just 7½ seconds.
The free-swinging mount on which the gun rested was originally equipped with open ring sights for aiming. Pointing and training were controlled through a set of handlebars and shoulder rests. The gunner had to lead the target in both traverse and elevation to achieve hits. A tracer was usually included in every fifth round to aid in spotting. By the middle of 1942, the open sights were being replaced by the Mark 14 gunsight.
Blandy wanted 20-mm Oerlikons eventually to replace every .50-caliber machine gun wherever the 20mm’s greater weight could be accommodated. The mount, he wrote, “remains as steady as a rock, despite . . . its heavier projectile and muzzle velocity of 2,720 feet per second.”
Navy, Merchant Marine, and Lend-Lease demand for the 20-mm antiaircraft guns became so great that by the beginning of 1942, production at the three companies had been ramped up to 3,250 guns a month. More than 460,000 American men and women would eventually be involved in making the weapon during the war.
The importance of the 20-mm Oerlikon to the war effort cannot be overstated. Between December 1941 and September 1944, gunfire from the weapon was responsible for 32 percent of all Japanese aircraft downed by the U.S. Navy.
Lieutenant Robert Wallace, the automatic weapons officer on board the USS Idaho (BB-42), left a vivid description of a 20-mm Oerlikon in action off Okinawa. A teen-age gunner opened fire on a kamikaze no more than one or two football fields away from the battleship while it tried to pass ahead of the ship. As Wallace observed, the young gunner “didn’t miss a beat in quickly getting a smooth track. He held his firing lever back for just 15 seconds, but that was enough. We could clearly see his tracers, in a full 90-degree deflection shot, seeming to curve into the cockpit. A ball of fire, the plane crashed harmlessly into the China Sea.”
By the end of 1944, the 20-mm Oerlikon’s importance had been overshadowed by the 40-mm Bofors’ greater hitting power and longer range. The enemy’s changing tactics and the Bofors’ increased volume and accuracy continued to reduce the comparative effectiveness of the smaller Oerlikon to the point where a large battery of the latter was neither necessary nor desirable.
The Oerlikon was also used on riverboats during the Vietnam War, Though information on this topic is scarce.
Product Options:
- Option 1: Demiled/Unrestored
- This is for those with the knowledge, skills, and facilities to restore and finish a torch-cut gun while ensuring compliance with ATF regulations.
- Includes: Demiled barrel, demiled receiver, recoil springs, recoil spring housing, barrel lock, top cover, rear cover, demiled side rails, and other small parts that are also demiled.
- Note: This option is recommended only for individuals experienced in restoration and familiar with ATF compliance.
- Option 2: Grade 2, Collector Grade Restoration
- Non-detailed restoration: Entire gun is bead-blasted and painted solid black.
- Key Features:
- No accents, and some areas may have light paint coverage due to painting as a complete assembly.
- No taping is performed, which may cause fitment issues with optional accessories such as the drum magazine, stock set, sight assembly, and display stands.
- Customers may need to remove paint in certain areas to ensure proper fitment of accessories, which can cause scratching of painted surfaces.
- Option 3: Grade 1, Museum Grade Restoration
- Extremely detailed restoration with many different accents and finishes.
- Key Features:
- Differing paint colors, polished and lacquer-sealed bolt carrier, parkerized parts, bodywork, and highlighted markings.
- Verified fitment and functionality of barrel lock mechanism, magazine lock and release mechanisms, safety selector, and trigger mechanism.
- Guns shown in some of the the included videos are Grade 1 restorations, showcasing the highest level of detail and craftsmanship.
Collector's Item:
Owning a 20mm Oerlikon Mark 4 Anti-Aircraft Gun Display means adding a genuine piece of naval warfare history to your collection. Whether you choose the demiled/unrestored option for a hands-on restoration project or one of the fully restored grades, this display gun offers a tangible connection to these weapons' significant role in World War II.
Why Choose Our Oerlikon Mark 4 Display:
Choosing the 20mm Oerlikon Mark 4 Anti-Aircraft Gun Display means investing in a piece of military history with assured authenticity and quality. Each restoration option is crafted to meet the needs and preferences of different collectors, ensuring compliance with ATF regulations. This display gun is an excellent addition to museums, educational institutions, and private collections, providing historical significance and visual appeal.
Please note that these are original WW2 guns that have gone through extensive demilitarization; therefore, there will be differences in the appearance of components and receivers. All guns will differ in the location of the torch cut. And/or small differences in the manufacture of all components, pictures, and videos are for representation only and do not reflect the exact gun you will receive.
Approx length ", Approx width ", Approx height ", Approx weight 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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