Inert 30mm Swiss dummy round used in the Oerlikon KCA. This 30x173mm shell casing is made of steel and is in good condition. The Oerlikon KCA is a Swiss 30mm gas-operated single-barrel revolver cannon developed for aircraft use. Its most noticeable use was on the JA 37 Viggen fighter mounted in a conformal pod as the akan m/75. The KCA fires a round that is 50% heavier than the NATO standard ammunition.