Oerlikon 20 mm aircraft guns

[Franz von Werra]

My collection of WWII artifacts includes a 20mm cartridge case.
I understand it belonged to a 20x110 RB round, as chambered by the Oerlikon S naval gun. However I am led to believe that it was fired by an aircraft gun, since it was found on a rooftop in a mountain village (so I was told).

What Allied aircraft may the 20x110 RB ammo be related to? Mosquito?

[brewerjerry]

Hi,
Maybe not a lot of use to you, but I was told that Oerlikon were fitted on some early typhoons, by a tiffie groundcrew man.
Although I have found no details in any books , etc..
Cheers
Jerry

[Tony Williams]

The Oerlikon Type S gun (which used the 20x110RB case) was not fitted to any British aircraft. Its main aircraft operational use was in some French fighters, although it was being replaced by the Hispano at the start of the war. The Hispano cartridge has very similar measurements (20x110) but the shoulder is less sloping and the rim is not rebated (in the Oerlikon case, the rim has a smaller diameter than the body). You can see these rounds illustrated in the pic from the Ammo Photo Gallery on my website. Be warned, though, a fired Oerlikon case had the neck 'blown out' - so it is better to look at the rim.

Tony Williams: Military gun and ammunition website and discussion forum