sentences:  In 1943 the revolutionary Mark 14 Gun Sight was introduced which made these guns even more effective; however, the 20 mm guns were found to be ineffective against the Japanese Kamikaze attacks used during the latter half of World War II.They were subsequently phased out in favor of the heavier 40 mm Bofors AA guns.Arguably the best light anti-aircraft weapon of World War II, the Bofors 40 mm anti-aircraft gun was used on almost every major warship in the US and UK fleet during World War II from about 1943 to 1945.