The Double-action Revolver is statistically the best of the three non-rare revolvers in the game. It also compares well to the rareLeMat Revolver which has a higher ammo capacity, but lower reload speed.
"Double action" describes a revolver in which pulling the trigger not only rotates the cylinder but also draws back the hammer, as opposed to single-action weapons which require the hammer to be cocked manually; this provides an increased rate of fire at the cost of a heavier trigger pull.
The Double-action Revolver can be found in the Tesoro Azulgang hideout. After completing the hideout, search a chest across from the room where the deputy was held hostage and the player will receive the revolver. Failing this, it is obtained by cracking the train safe in the mission The Great Mexican Train Robbery.
Since there are only six rounds in the gun, combined with a slow reload and higher rate of fire, the player will find themselves reloading more than usual, thus leaving themselves open to enemy fire more often. Pacing and choosing shots is important.
At mid-range, it's recommended to wait until a relatively clear target is presented and then fire, lest the gun empties before a kill is made.
When in a firefight against an opponent using the Double-action Revolver, roll and take cover until they empty their gun or have an insufficient number of rounds to finish the player off.
If caught reloading while an enemy is advancing, equip a shotgun or even the knife to finish off the opponent if the opportunity presents itself or flee.
The high rate of fire does mean it's handy in close quarters at a pinch, or for surprise attacks or the like when one doesn't have enough Dead Eye. Aim for center mass and empty the magazine.
Knowing your hotkeys and your weapon wheel is a handy skill when using this gun, as the fast fire rate and slow reload can be problematic if faced with multiple enemies, or enemies who advance on you. Be prepared to swap guns.
The Double-action Revolver is the only one in-game that utilizes a swing out cylinder, compared to top-break or loading gate methods. In real life this is a much faster way of reloading than the "Cattleman"/Peacemaker's loading gate system.
It seems that Harold Thornton uses a rather unique version of this revolver, having a shiny steel finish compared to the usual dark one.
Marston will still fan the hammer of the Double-action Revolver like a Single-action weapon during duels.
The hammer is left in the uncocked position right after reloading until a shot is fired. After firing the first shot, the hammer becomes cocked and will be cocked back for the remainder of the rounds in the cylinder or at least until the next reload. This odd occurrence affects all firearms with a visible hammer in single and multiplayer.