Staff Writer (Updated: 8/12/2014):
In the time leading up to Colt's excellent SAA design, a key patent owned by Smith & Wesson - noted as the "Rollin White Patent" of 1855 - protected the use of a "bored-through" cylinder design utilizing metallic cartridges. Once the patent had expired in 1869, the field was open for any and every firearms firm to move in and develop their own designs and a plethora of revolvers soon permeated the gun markets from America to Europe. In 1873, the US Government was on the lookout for a new service revolver aimed at arming Cavalry elements, prompting Colt's Patent Firearms Manufacturing Company (founder Samuel Colt passed away in January of 1862) to lend its talents in supplying the required piece. After successfully clearing evaluation, the Colt design was accepted into service with a signed procurement contract as put forth by the US Army. From there, the legacy of the fabled "Colt 45" was secured. Upon entering service, the new Colt Single Action Army replaced the outgoing Colt Model 1860 Army percussion cap revolvers then in service.
Interestingly, the Model 1873 was nothing overtly special in its design, form and function. The heart and soul of the firearm was naturally its six-round, rotating cylinder nestled within a bridged frame. The receiver was solid and contained the major working components to manage the cylinder, trigger and hammer functions. The barrel was fitted ahead with the extractor rod installed underneath. A blade-and-notch sight was standard on early production models. The hammer was clearly visible at the rear of the receiver while the pistol grip was adorned with wood for a relatively comfortable hold. The trigger was set low in the design, protected by an oblong ring. The Colt 45 was characterized in type as a centerfire, single-action revolver, based on both the type of ammunition it fired (black powder centerfire) and the key function of the trigger itself.