William Mason (Colt) - Colt

Colt

Mason left Remington Arms in 1869 to work for Colt as the Superintendent of the armory. Along with Charles Richards, Mason patented designs to convert percussion revolvers into rear-loading metallic cartridge revolvers. Those converted revolvers are identified as the "Richards-Mason conversion". After working on these conversions, Mason began work on Colt's first metallic cartridge revolver in 1871: the Colt Open-Top revolver. This was a completely new design and the parts would not interchange with the older percussion pistols. Mason moved the rear sight to the rear of the barrel as opposed to the hammer or the breechblock of the earlier efforts. The caliber was .44 rimfire and it was submitted to the US Army for testing in 1872. The Army rejected the pistol and asked for a more powerful caliber with a stronger frame. Mason redesigned the frame to incorporate a topstrap, similar to the Remington revolvers and placed the rear sight on the rear of the frame. The first prototype was chambered in .44 rimfire, but the first model was in the newest caliber known as the .45 Colt.

The revolver was chosen by the Army in 1872, with the first order shipping in the summer of 1873 for 8000 revolvers. After the success of the Colt Single Action Army and Colt's conversion of existing percussion revolvers to Richards-Mason conversions, Mason went on to design Colt's smallest revolver, "The New Line" in 1874. There were 5 variants, each differing in size and caliber, but all using a breechblock designed by Mason.

While Colt had first developed the concept of a "double-action" revolver as early as 1857 and a patent was filed, it was never built by Colt. With increased competition from their British rival, Webley & Scott, Colt had Mason design a double-action revolver for them in 1877, the Colt M1877. Following this, Mason once again teamed up with Richards to produce a larger framed version, the Colt M1878 Frontier in 1878.

His final design for Colt was the Colt M1889, a collaboration with Carl J. Ehbets for a revolver with a swing-out cylinder. Ehbets continued to perfect the idea for 7 years after Mason left Colt for Winchester.