Samuel Colt new revolver had a stationary trigger and was in a larger caliber. Colt submitted his single prototype to the War Department as a "Holster revolver". Captain Samuel Walker of the Texas Rangers had acquired some of the first Colt revolvers produced during the Seminole War and saw first-hand their effective use as his 15-man unit defeated a larger force of 70 Comanche in Texas. Walker wanted to order Colt revolvers for use by the Rangers in the Mexican–American War, and traveled to New York City in search of Colt. He met Colt in a gunsmith's shop on January 4, 1847,
William Mason (Colt) 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