Final answer:
The M9 pistol is a semi-automatic, 9mm firearm that served as the US armed forces' standard sidearm. Developed by Beretta, it has a 15-round magazine and offers single and double-action capabilities.
Step-by-step explanation:
The M9 pistol is a semi-automatic firearm developed for military use, primarily serving as the standard sidearm for the United States armed forces from 1985 until 2019. It utilizes a 9mm caliber round and is designed for short-range engagement. Featuring a 15-round magazine capacity, the M9 provides both single and double-action capabilities, with a double-action first trigger pull followed by a lighter, single-action pull for subsequent shots. Developed by the Italian company Beretta, the full-size pistol has also seen widespread use in law enforcement agencies and civilian markets around the world.