Thanks to Carlos Villarroel for supplying information for this article


In the early 1960s the state-operated CETME arsenal (Centro de Estudios Tecnicos de Materiales Especiales) in Spain began development of a submachine gun. The lead designer on this project was the former director of the Coruña arsenal, Joaquin de la Calzada de Bayo. An early prototype was conceived in 1961 and was known as the CB-61 (Calzada Bayo). The design of this gun was clearly derived from the British Sterling submachine gun, using a similar trigger group and tubular receiver with perforations around the barrel. However on the CB-61, the magazine feed was vertical.

The CETME CB-61 prototype with vertical magazine feed (Photo: Barcelo Rubi)

Over the next few years the design was further refined and by the mid-1960s it was known as the CB-64. This was largely the same gun but with various detail changes, such as the relocation of the magazine feed to a horizontal position, as per the Sterling, and the slight changes to the sights and position of the cocking slot. The bolt on the CB-64 used a loose, spring-loaded firing pin engaged by a separate hammer, and fired from an open bolt position. The gun is chambered in both 9x23mm Largo, the standard Spanish pistol cartridge, and 9x19mm Parabellum, without the need to swap many components as the two cartridges are dimensionally similar. The cocking handle on the CB-64 is also built onto a rectangular dust cover, which conceals the cocking slot.

The end product is largely indistinguishable from the original Sterling submachine gun, but internally the CB-64 does include an interesting feature not present on the Sterling. A common hazard of open-bolt SMGs if that when the bolt is in the retracted position, i.e. cocked and ready to fire, dropping the gun can cause the bolt to come loose and fly forward, resulting in an accidental discharge which can prove fatal, and indeed has in many cases. Mr. Calzada de Bayo built the CB-64 with a failsafe mechanism that prevents the bolt from coming forward unless the trigger is actually pulled. This is achieved by fitting the trigger sear with an extension that engages a catch in the bolt path. The catch interrupts the bolt path and prevents the bolt from coming forward, but does not prevent the bolt from coming back (i.e. cocking). Only by deliberately pressing down the trigger and fully engaging the sear does the catch come down and open the bolt path.

CETME CB-64 safety
The CETME CB-64's failsafe safety catch.

The CB-64 was offered for domestic and export sale in the 1960s under the name "CETME C2". However it did not sell particularly well and was discontinued by the mid-1970s. There were apparently plans to reintroduce it to CETME's sales line at the end of the 70s but this amounted to nothing.

CETME CB-64 CB-64 patent

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