Artillery in Canada: 20-mm Oerlikon anti-aircraft gun

20-mm Oerlikon anti-aircraft gun

(Library and Archives Canada Photo, MIKAN No. 3204508)

Twin 20-mm Oerlikon anti-aircraft guns aboard a motor torpedo boat (MTB) of the Canadian-manned 29th MTB Flotilla, RN, May 1944.

(Library and Archives Canada Photo, MIKAN No. 3509541)

The crew of one of HMCS Iroquois' Oerlikon anti-aircraft guns at action stations during a training exercise off Halifax, Nova Scotia, 2 June 1944.

(Library and Archives Canada Photo, MIKAN No. 3560470)

Personnel of a Canadian Highland regiment receiving training about the Oerlikon 20-mm gun aboard the troopship HMT Nea Hellas en route to Philippeville, Algeria, 5 July 1943.

(Library and Archives Canada Photo, MIKAN No. 3525061)

A 20mm Oerlikon anti-aircraft gun and its crew aboard HMCS Morden, Halifax, Nova Scotia, 3 August 1943.

(IWM Photo 4700-01)

Oerlikon 20-mm/70 Light Anti-Aircraft Gun on HMS Hermione.  The naval gunner utilising the rubber shoulder rests for high-angle firing.  Note the Thornycroft depth charge thrower Mk. II and depth charge launching rail in the background.

The Oerlikon 20-mm had a simple blow-back design (unusual for a high powered autocannon), meant that force of the round would cycle the breech against a powerful recoil spring that wrapped around the barrel.  With a cyclic rate of 480 rounds-per-minute, and fed by a drum magazine of 60 rounds, the weapon would keep firing as long as the firing lever was held back or until something broke.  The Oerlikon 20-mm had an effective range of 1,500 metres,

The Royal Canadian Navy (RCN) popularized the use of the Oerlikon gun as an anti-ship and anti-submarine gun.  While it was not effective against the armour of most larger ships, it was used extensively and effectively against U-boats, and on the decks of larger ships.  A handful of corvettes were fitted with the weapon toward the end of the war, but it appeared more commonly on frigates and destroyers at the time.  The Oerlikon was also used as the basis for the Polsten gun.

(Library and Archives Canada Photo, MIKAN No. 3205256)

Oerlikon 20-mm Anti-Aircraft Gun, HMCS Prince Henry, Normandy, 6 June 1944.

(Library and Archives Canada Photo, MIKAN No. 3612508)

Oerlikon 20-mm Anti-Aircraft Gun, HMCS Prince Henry.

(Library and Archives Canada Photo, MIKAN No. 3394410)

Oerlikon 20-mm/70 Light Anti-Aircraft Gun manned on HMCS Prince David, off Kithera, Greece, 16 Sep 1944.

(Library and Archives Canada Photo, MIKAN No. 3627546)

Workmen install twin Oerlikon guns in place of a single Oerlikon gun during carrier modification at Burrard Shipyard's Lapointe Pier, May 1944.

(Author Photos)

20-mm/70 Oerlikon AA Gun Mk. 4, (Serial No. 215716), mounted on a naval gun stand.

(Author Photo)

Oerlikon 20-mm/70 Light Anti-Aircraft Gun, (Serial No. 702), 1944.  Naval Museum of Alberta, Calgary, Alberta.

(Author Photo)

Oerlikon 20-mm/70 Light Anti-Aircraft Gun, (Serial No. 2), 1942.  Naval Museum of Alberta, Calgary, Alberta.

(Library and Archives Canada Photo, MIKAN No. 3238905)

20-mm Oerlikon AA Gun manned on the roof of the Canadian Military Headquarters (CMHQ), London, UK, ca 1942.

(Library and Archives Canada Photo, MIKAN No. 3607578)

20-mm Oerlikon AA Gun manned on the roof of the Canadian Military Headquarters (CMHQ), London, UK, ca 1942.

(Library and Archives Canada Photo, MIKAN No. 3516225)

20-mm Oerlikon AAGun manned by a soldier of the Saskatoon Light Infantry (MG), Spinazzola, Italy, 1 Oct 1943.

(Library and Archives Canada Photo, MIKAN No. 3197400)

20-mm Oerlikon AA Gun being tested for range of motion onboard a ship, Vancouver, BC, May 1944.

(Library and Archives Canada Photo, MIKAN No. 3303867)

Oerlikon 20-mm AA Gun mounted on a Landing Craft Infantry (LCI), RCN, May 1944.

(Library and Archives Canada Photo, MIKAN No. 3201902)

Defensively Armed Merchant Sips (DEMS) personnel learning to fire an Oerlikon 20-mm/70 Light Anti-Aircraft gun, Esquimalt, British Columbia, 15 March 1944.

(Author Photos)

Oerlikon 20-mm/70 Mk. 4 Light Anti-Aircraft Gun  on an RCN Mk. V Mounting.

(Author Photos)

Oerlikon 20-mm/70 Light Anti-Aircraft Gun, inside the New Brunswick Military History Museum, 5 Canadian Division Support Base Gagetown, New Brunswick.

(Author Photo)

Oerlikon 20-mm/70 Light Anti-Aircraft Gun, inside the Army Museum in the Citadel, Halifax, Nova Scotia..

(Library and Archives Canada Photo, MIKAN No. 3394409)

20-mm Hispano AA gun, ammunition drum change, Halifax, May 1941.

(Library and Archives Canada Photo, MIKAN No. 3613101)

20-mm Hispano A/7K Gun, c1940.

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