Inert 25mm Swiss armor-piercing discarding-sabot round used in the 25mm Oerlikon KBB. This 25x172mm shell casing is made of steel and is in good condition. The 25mm Oerlikon KBB was an autocannon developed by Switzerland in 1974 and entered into service in 1986. It is a gas-operated autocannon with a double feed mechanism and multi-slotted muzzle brake.