The Madsen Model 1902 Light Machine Gun was originally conceived in 1880, with primitive prototypes seen around 1883. Very light (at 20 pounds), the weapon is considered to be the first "true" machine gun put into mass production. By World War One, thousands of production models were sold to Russia and other Countries. Well made, the time consuming assembly made The Madsen very expensive. Capable of firing up to 450 rounds per minute. It was available up to 25 different calibers, the two most popular were the 6.5mm and 7.92mm. It had an effective range of over 800 yards with a maximum effective range of over 2,000 yards. The Madsen Machine Gun was made in both Infantry and Aircraft versions (with an Armor Model for tanks as well). It also is considered one of the longest running production guns in The World, with the last retired in 2008.