The Probert Encyclopaedia of Warfare

HECKLER AND KOCH USP

The Heckler and Koch USP (Universal Self-loading Pistol) is a German recoil-operated, semi-automatic pistol with a redesigned Browning action available in 9 mm, .40 Smith and Wesson and .45 ACP calibres, taking a 15-round, 13-round or 10-round magazine respectively. Ten variants are also manufactured offering single/double-action or double-action only (DAO), controls on the left or right side, with and without manual safety catch, and manual or automatic decocking.
Research Heckler and Koch USP