The mares leg is a twelve inch lever action pistol. It is a cut down version of the Winchester Model 1892, originally used by actor Steve McQueen in "Wanted: Dead or Alive". It is also called the Winchester Randall, in honor of McQueen's character, Josh Randall. It is chambered in .44-40, and is usually used with the .44 Winchester Center Fire cartridges. The gun itself gained popularity in the '50's cowboy Westerns, and was recently used in the movie "Zombieland" by a character named Tallahassee.
As the Randall is a rifle whose barrel is cut down to under 16 inches, it is required to be approved by the BATFE in the United States, under the National Firearms Act. The owner is also subject to a $200 tax, although these restrictions are not applicable if the firearm has been built as a "lever-action pistol".