The Beretta M9, officially the Pistol, Semiautomatic, 9mm, M9, is a 9×19mm Parabellum pistol adopted by the United States Armed Forces in 1985. It is essentially a military specification Beretta 92FS. The M9 won a competition in the 1980s to replace the M1911A1 as the primary sidearm of the U.S. military, beating many other contenders, and only narrowly defeating the SIG P226 for cost reasons. It officially entered service in 1990. Some other models have been adopted to a lesser extent, namely the M11 pistol, and other models remain in use in certain niches.