This is the pistol adopted by the U.S. Army in 1875. This particular model takes a .45 caliber. In the hands of a proficient gunner, this weapon can be fired 18 times in 1.5 minutes. The muzzle velocity of this pistol is about 810 ft. per second.
The old pistol is a .45 caliber revolver originally used by gold miner Nate Harlow. It is one of the weakest firearms in Red Dead Revolver, possessing a very short range and low stopping power. In return, however, it possesses a fairly fast reloading speed and an above average accuracy rate.
It is the very first weapon obtained by the player in Revolver. After creating the Scorpion Revolvers, Nate gifted the old pistol to his son, Red Harlow, which he used for practice and fight off bandits sent by Colonel Daren.
Sheriff Bartlett's Journal
Old Pistol is listed in Sheriff Bartlett's Journal on pages 26 - 27 under the Side Arms section. The pages are available from the beginning of the game and do not need to be unlocked.