FNA-B X4 & X5


In the mid-1950s, the Brescia firm of Fabrica Nazionale d'Armie (FNA-B) offered a pair of compact submachine guns for commercial export, known as the X4 and X5. These guns were basic blowback SMGs employing a short bolt with rubber buffer and wide diameter return spring. Interestingly there was no cocking slot, but instead a cylindrical sleeve, pinned to both sides of the bolt, which enveloped the receiver in a similar fashion to the earlier Revelli O.V.P. from the 1920s. The unusually wide magazine well housed, in its front part, a spring securing the barrel-locking nut. This mag well took standard Beretta Model 38 magazines.

Both the X4 and X5 were functionally identical, and the differences lay only in length. The X4 had a 7.8in barrel and retracting wireframe stock, whereas the X5 had a very short 4.6in barrel and no stock whatsoever. In fact, the X5 held the distinction at its time of being the shortest SMG on the market, at only 12.4in overall.

FNA-B X5 sketch
Cross-section sketch of the X5. There were 51 parts in total.

The project was an ambitious venture for FNA-B, who advertised a production run of some 100,000 units at a projected cost of only $15 per unit. Indeed, built almost entirely from stamped steel, these guns were incredibly cost-efficient and simple to produce, so it is surprising that there was a considerable lack of interest in the X4 and X5 at the time. No major orders were placed, the proposed 100,000-unit run was never produced, and the guns were discontinued by the end of the decade. The X4 and X5 have since been entirely forgotten.

There has been an interesting development, however. By complete chance, I came across a photograph published in October 1956 which clearly shows an X5 submachine gun, confiscated by French authorities from FLN rebels upon their return to Algiers from Tunisia. The contemporary caption attached to this photo misidentifies the gun as a Beretta SMG, however I recognized it instantly.

FNA-B X5 Algiers

So it would appear that the X5 did see some use after all!

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