sentences:  Although a descendant of German and Swedish designs, the Bofors mounts used by the US Navy during World War II had been heavily "Americanized" to bring the guns up to the standards placed on them by the US Navy.This resulted in a guns system set to English standards (now known as the Standard System) with interchangeable ammunition, which simplified the logistics situation for World War II.When coupled with electric-hydraulic drives for greater speed and the Mark 51 Director ("pictured") for improved accuracy, the Bofors 40 mm gun became a fearsome adversary, accounting for roughly half of all Japanese aircraft shot down between 1 October 1944 and 1 February 1945.