My favorite westerns were those featuring unusual firearms:
Yancy Derringer - well named since he carried six of them including one in his hat. His sidekick Pahoo had a sawed off shotgun under his blanket.
The Rifleman - 1892 Winchester modified into 20 round slow cyclic rate machine gun. Count the # of rounds fired in the intro. Lucas McCain took out a bad guy who was terrorizing the land with a Sharps rifle which had a full length telescope sight.
Johnny Ringo - Le Mat revolver with its seven shot cylinder & shotgun barrel left many a bad guy dead with a surprised look on his face.
Shotgun Slade - sawed off over/under rifle-shotgun. A one season wonder.
Wanted Dead or Alive - “mare’s leg” cut down Winchester 92. Fired as many shots as full length model. Oversize rounds carried in cartridge belt for effect. Harassed by BATF during filming.
Have Gun Will Travel - Remington derringer in addition to sixgun.
Bat Masterson - short barrelled “Sheriff’s Model” sixgun.
The Rebel - Johnny Yuma sported a sawed off shotgun plus a cap & ball revolver which fired & reloaded just as fast as a cartridge sixgun.
Wild Wild West must have had some anachronistic firearms but I can’t think of any offhand. Maybe a broomhandle Mauser.
Pahoo Ka Ta Wah....wolf who stands in water played by Ed Ames.