Lt. John J. Dunbar (Kevin Costner) keeps a Colt 1851 Navy as his sidearm throughout the film. It is actually converted to fire metallic cartridges which is safer then using blanks on a percussion revolver. Also seen in the hands of some high ranking Union officers. Major Fambrough (Maury Chaykin) kills himself with one. Also John Dunbar's revolver could be considered as slightly anachronistic due to its model type. This particular revolver was built in London, England due to its appearance being a steel frame with black iron backstrap and black steel barrel. As only around 2,000 units were produced at the London Colt factory it is highly unlikely that John would come by one.
Henry 1860
Lt. John J. Dunbar (Kevin Costner) keeps a polished brass frame Henry 1860 rifle, or as the Rebels called it, "That damned Yankee rifle you load on Sunday and shoot all week", as his main weapon of choice throughout the film.
Springfield 1861
Dunbar's sergeant friend can be seen loading an Enfield 1853, not a Springfield 1861 as previously thought. This can be determined due 1. the shape of the ramrod end, being cylindrical in shape with a square hole punched through it for a jag cleaning cloth, unlike a more bulbous plain ramrod of the Springfield 1861. 2. Because of the shape of the barrel bands being a more rounded shape from being cast, much unlike the barrel bands of a Springfield 1861 which are produced by being pressed and stamped.
Enfield 1853
Confederate soldiers carry Springfield 1851 and Enfield 1853 rifles as their standard issue weapons.
Union soldiers are seen armed with Colt 1860 Army revolvers as their sidearms.
Sharps 1863
To prepare for the attacking Pawnee Indians, Dunbar gives the Sioux Indians Sharps rifles, which based on the time are 1863 models.
Sharps 1863 Saddle Ring Carbine
Dunbar also gives many of the Sioux Sharps Saddle Ring carbines, also assumed to be the 1863 model. Union soldiers are later seen almost entirely armed with Sharps Carbines in the film, and use them to sadly shoot down Dunbar's pet wolf, Two Socks.
12 Gauge Double Barreled Shotgun Muzzleloaders are seen used by some of the Confederate soldiers at the beginning of the film and Timmons (Robert Pastorelli) keeps one at his side while driving Dunbar in his coach. They are noted as muzzle loaders based on the ramrod underslung under the barrels.