Josey Wales (Clint Eastwood) carries two Colt Walker 1847 revolvers in twin holsters as his primary sidearms, although he carries four pistols in total. While not supposed to be known by the audience, the guns are converted to fire metallic cartridges instead of firing percussion cap and ball, since this it is safer to use blanks than firing blackpowder blank shot. While some of the guns are anachronistically seen with conventional metallic conversion kits with ejector rods and loading gates, these guns lack these features to try to hide its conversion. In some scenes though, the guns are non-firing models which do have percussion nipples so the audience can be tricked into thinking the guns are a percussion only. The famous image in which Wales poses with his Colt Walkers is a good example.
Colt 1860 with Richardson-Mason conversion
This revolver is either a Colt 1860 Army converted to accommodate metallic cartridges, or a Colt model 1871-72 Open Top Model (note the extractor, and the loading gate)
I belive that this is a Richards conversion, not Richards- Mason. You can see the rear sight on the breech ring, the R-M used the original hammer sight. Also, the hammer has been modified to strike the frame mounted firing pin used in the Richards
Colt 1860 Army
Carried and used by Wales as well as other characters throughout the film.
Colt 1849 Pocket
Model 1865 Gatling Gun
Used by Union troops to mow down Wale's comrades after they surrender. Wales kills one of the gun's team then uses it to mow down Union troops and destroy the other gun.
Springfield 1861 rifle
Used extensively throughout the film by various characters. It's also likely that some of the rifles are the 1863 model.