The term "six-shooter" evolved from the revolver developed from the old "cap-and'ball" one-shot gun into one that would shoot six times. The Texas Rangers coined the phrase. The "Single-Action Army" Colt was nicknamed the "Peace-maker" and "Hog-leg". The term "Hog-leg" was also used on any frontier pistol.
The single-action pistol was referred to as a "thumb-buster." and a modelw ith a semi-round butt was called a "parrot-bill."
Other names used for personal weapons were:
A pistol was always called a gun but a rifle with the exception fo a "buffalo gun" was never called a gun. They were:
Shotguns were Scatter-guns
Source: Cowboy Lingo by Ramon F. Adams