The Revolver is a standard sidearm used in Red Dead Revolver, with no distinguishing attributes, besides having a very decent accuracy and fast reloading speed. Statistically, it's the third weakest sidearm in the game, with only the Old Pistol and Six-Shooter being weaker.
A dual version of the weapon, dubbed in-game Twin Revolvers, are available halfway through the single-player mode. Another dual variation, called "Showstoppers", exists as a personal weapon for the one-time playable character Jack Swift.
Sheriff Bartlett's Journal
Revolver is listed in Sheriff Bartlett's Journal on pages 28 - 29 under the Side Arms section. The pages are unlocked by purchasing the weapon.