The Browning Hi-Power is a single-action, 9 mm semi-automatic pistol. It is based on ideas conceived and patented in 1922 by American firearms inventor John Browning, and later patented by Fabrique Nationale (FN) of Herstal, Belgium. Browning died in 1926, before he had finished developing a production version. The design was fully developed and realized by Belgian arms designer Dieudonne Saive, working at FN.
The Hi-Power pistol was named for its 13-round magazine capacity, which was almost twice that of contemporary designs such as the Luger or Mauser 1910. The Hi-Power had the first functional double-column magazine of 9 mm rounds, and was capable of holding 13 cartridges, with a 14th loaded in the chamber. Flush-fit 15 round magazines are now available, as well as higher capacity magazines which extend past the end of the butt.
The pistol is often referred to as an HP (for “Hi-Power” or “High-Power”) or as a GP (for the French term, “Grande Puissance”). The term P-35 is also used, based on the introduction of the pistol in 1935. Another common nickname is the “King of Nines.” It is most often called the “Hi-Power”, even in Belgium. It is also known as the BAP (Browning Automatic Pistol), particularly in Irish service.