Stamps on side of projectile read;
When originally produced, the series of 30 mm automatic cannon now generally known as the Oerlikon Contraves 30 170 KCB series was designated the Hispano-Suiza HS-831 series. The designation was officially changed when Hispano-Suiza became part of Oerlikon Contraves AG but is often retained. The 30 mm cannon design involved was virtually a scaled-up version of the 20 mm HS-820 (now known as the Type KAD) cannon and has been produced in several forms.
Two different loadings of the 30 170 have seen service. The original type was for the HS-831A gun, used only by France (in the AMX 13 SPAAG) and Saudi Arabia (AMX 30 SPAAG). These were mainly brass-cased, and used heavy shells with a conical ogive and a brass driving band. Muzzle velocity was 920 m/s. Most production is for the slightly modified HS-831L: this uses steel cases with lighter shells having a more conventional ogive and sintered iron driving bands. Muzzle velocity is 1,080 m/s. The two types are not interchangeable due to the different ballistics.
RWM Schweiz's KCB ammunition family was used as the basis for the 30 mm Rarden gun ammunition family but ammunition for the KCB and Rarden L21 is not qualified as inter-operable.
Charlie, just a thought - could this be tied into the development of the Vickers/BMARCo. ''Falcon'' A.A. twin cannon self-propelled equipment ?? Regards, RonB. Development was late 50's - into early 60's.Stamps on side of projectile read;