Former Confederate soldier Cullen Bohannon (Anson Mount) carries a Confederate-made Griswold & Gunnison Revolver in "Pilot" (S1E01), by which he is recognized. This weapon is only mainly seen in the pilot episode, after which Cullen Bohannon carries a Colt 1860 Army revolver as his main sidearm for the rest of the season. The Griswold & Gunnison revolver is also seen firing during a continuity error in "A New Birth of Freedom" (S1E03).
Colt 1860 Army
Cullen Bohannon (Anson Mount) carries a Colt 1860 Army revolver as his sidearm after the pilot.The 1860 was the most common handgun in the United States at the time, most had a brass trigger guard (see photo), they were not manufactured with a brass frame like the Griswold above. Several other characters carry and use the Colt 1860 Army revolver throughout the season, including Elam Ferguson (Common). Bolan (Ian Tracey) also uses a Colt 1860 Army in "A New Birth of Freedom" (S1E03), instead of his usual sidearm, the Remington 1858 New Model Army.
The brass framed pistol Bohannon uses in the opening episode is neither an 1860 nor a Griswold but is an amalgam reproduction that was likely used as a stop gap piece for filming.
Colt 1851 Navy (Brass Frame)
Gregory Toole (Duncan Ollerenshaw) uses a Colt 1851 Navy revolver as his sidearm throughout the season. Elam Ferguson (Common) also carries on as his sidearm after he becomes the Chief of Railroad Police. Several other people carry these revolvers as well. Most of these appear to be brass-framed copies of the Colt 1851 Navy revolver, which did not exist until the Italians started making them during the 1960s.
Remington 1858 New Army
Former Union soldier Daniel Johnson (Ted Levine) carries a Remington 1858 New Army in "Pilot" (S1E01). Bolan (Ian Tracey), and other characters also carry Remington 1858 New Armys as their sidearms during the season. Most of the Remingtons appear to be modern and unauthentic replicas, known as "Texas Models", because brass-framed Remingtons were never manufactured.
Allen & Thurber Pepperbox
Thomas Durant (Colm Meaney) pulls out an Allen & Thurber Pepperbox revoler in "Immoral Mathematics" (S1E02) when he converses with Cullen Bohannon.
Flintlock Pistol
A Flintlock pistol is visible on Thomas Durant's wall in "Jamais Je Ne T'oublierai" (S1E04).
Rifles
Winchester 1866 "Yellowboy"
The Winchester 1866 "Yellow Boy" rifle is prevalent in many episodes, especially in "Timshel" (S1E09). The rifle, while period correct, would not have been issued to the US Cavalry as portrayed in the series. It is used by many characters throughout the series, and Cullen Bohannon (Anson Mount) carries one on his saddle throughout the season.