The 1911 A1 is a semi-automatic pistol designed by John Browning and adopted by the United States military in 1911. It features a single-action mechanism and is chambered primarily for the .45 ACP cartridge. The design is known for its reliability, accuracy, and ease of use, making it a popular choice among military and civilian shooters alike. The 1911 A1 is an updated version of the original 1911, incorporating several improvements such as a longer grip safety and a wider rear sight. It has a magazine capacity of seven rounds and is often praised for its ergonomic design and smooth trigger pull, contributing to its enduring popularity in firearms history.