in Herstal, Belgium, as a private export venture during the final years prior to World War II.

[2] Even though it gained great interest during its limited time on the export market, it only managed to be exported to the air forces of Romania and Sweden prior to the German invasion of Belgium in 1940, later also being pirate produced in Finland with the help from Sweden.

[2] Due to the above-mentioned features, the 13.2 mm FN Browning drew a lot of interest from a number of nations when it entered the export market in 1939.

[15] However with the start of WW2, and the subsequent invasion and occupation of Belgium by Nazi Germany in the summer of 1940, the 13.2 mm FN Browning was, in that limited time, only exported to Romania[6] and Sweden.

[8] Due to insufficient documentation and construction quality, a number of changes had to be made to the weapon design for Swedish production to begin, leading to a new variant being produced.

[3] After the war it became apparent that 13.2×99mm ammunition would be too expensive to come by and with the purchase of surplus P-51D Mustangs (in Sweden designated J 26) armed with 12.7×99mm AN-M2 Browning guns in 1945, it was decided in 1947 to re-chamber the 13.2 mm akan m/39 guns for the readily available 12.7×99mm Browning (.50 BMG) cartridge.

From the early 1950s onward however, the 12 mm akan m/39 started being used as a training weapon for jet fighters, such as the de Havilland J 28 Vampire[17] and the SAAB J 29 Tunnan,[18] were it could be mounted in place of their main cannon armament by the use of a small add-on.

After WWII the Finnish would use the 12,70 LKk/42 as training weaponry in aircraft such as the Saab 35 Draken and BAE Hawk.