This was the first semi-automatic pistol that John Browning designed. It used a .38 caliber round with a single stack magazine. That remained the standard magazine design until the John Browning Designed Hi-Power (Patent 1618510), which used a double stack magazine. He was granted US Patent 580923 for this design on April 20th, 1897. Browning had applied for this Patent almost two years earlier, on September 14th, 1895. Patent 580923 was sold to Colt, but Colt never manufactured this particular design.