m/39 and was later produced by Ericsson as the Akan m/39A. Sweden also gave the blueprints to Finland so they could produce the weapon. Since Finland was already producing 12.7 mm ammunition, the Finnish variant was rechambered to 12.7 mm (.50 BMG). The Finnish variant was designated VKT 12,70 LKk/42 and was produced by the state of Finland. Aircraft guns .50 Browning AN/M2 The M2 machine gun was widely used during World War II, and in later postwar conflicts, as a remote or flexible aircraft gun. For fixed (offensive) or flexible (defensive) guns used in aircraft, a dedicated M2 version was developed called the ".50 Browning AN/M2" or the "12.7 mm AN/M2". The "AN" stands for "Army/Navy", since the gun was developed jointly for use by both services. The AN/M2 designation was also used for other aircraft guns and therefore it is important to write the caliber before the designation. The 12.7 mm AN/M2 had a cyclic rate of 600–800 rounds per minute, with the ability to be fired from an electrically operated remote-mount solenoid trigger when installed as a fixed gun. Cooled by the aircraft's slip-stream, the air-cooled 12.7 mm AN/M2 was fitted with a substantially lighter length barrel, reducing the weight of the complete unit to , which also had the effect of increasing the rate of fire. The full official designation for this weapon was "Browning Machine Gun, Aircraft, Cal. .50, AN/M2" (Fixed) or (Flexible). The 12.7 mm AN/M2 was used on many aircraft during WWII, as it served as the main aircraft armament in the US military. Most US fighter aircraft were armed with four, six or eight AN/M2 MGs mounted in the wings. Some famous examples being the P-40, P-47, and P-51 for the USAAF and the F4F, F6F, and F4U for the US Navy. For bombers, the AN/M2 was used in both flexible and fixed positions for both offensive and defensive use. In flexible defensive positions, the B-17G Flying Fortress heavy bomber was armed with 13x AN/M2 guns in both turreted and flexible positions. In fixed offensive configurations, like on the B-25 Mitchell, commonly carried 6 to 12 fixed guns for strafing. In foreign use the AN/M2 is often just referred to as the M2 Browning. In Sweden it was re-designated 12,7 mm automatkanon m/45 (short 12.7mm akan m/45) meaning 12.7 mm autocannon m/45. Note the Swedish Air Force used a different designation system