40mm Gun Firing (sound only) • 40mm Gun Training Video
- 40mm Anti-Aircraft Gun Mount Mark 1 Twin — OD 3782
- 40mm Anti-Aircraft Gun Mount Mark 2 Quad — OD 4391
- 40mm Anti-Aircraft Gun Mount — OP 820
40mm Machine Gun Mechanism, Mark 1, Mark 2, Mark 1 Mod 1, Mark 2 Mod 1
The power drives for the Twin and Quad gun mounts were designed and built by the York Safe and Lock Co. These drives used a clutch mechanism which salt water would wet, causing the drive to be jumpy, jerky, and prone to slipping — requiring constant maintenance.
The 40mm gun described in OP 820 had hydraulic drives and was used to replace the York Safe and Lock drive on the above gun mounts.
In the first year of the war the 20mm gun and the 1.1" gun shot down the most aircraft of any gun system in the fleet. The Mark 14 gun sight was first adapted to the 20mm and 1.1" gun at about the mid-point of 1942 as it became available. These were the primary air defense weapons at the time. The 1.1" gun quickly went out of service as 40mm gun mounts became available; the 20mm served by the thousands until the end of the war and beyond.
The 40mm gun and the Mark 14 Gun Sight began to arrive in large numbers in the fleet by 1942, and this combination gets the blue ribbon for shooting down the most aircraft during the war.
