Mondragón Rifle : Livre de poche, 84 pages, Frederic P. Miller, Agnes F. Vandome, OmniScriptum

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Mondragón was the world's first semi-automatic rifle, and was designed by Mexican general Manuel Mondragón. He began work in 1882 and patented the weapon in 1887. It was gas-operated with a cylinder and piston arrangement, now very familiar but unusual at the time, and rotating bolt, locked by lugs in helical grooves in the receiver; it was also possible to operate it as a simple straight-pull bolt action. The caliber was 7 mm (.284 in) Mauser with an 8-round box magazine; a trial LMG version had a 20-round box and provision for a bipod, like the BAR; the Mexican Army also used a 100-round drum magazine for a light machine gun variant produced in 1910.