Red Dead Redemption 2: how to unlock the Double-Action Revolver and where to find it
If you’re looking to start Red Dead Redemption 2 with a tasty pistol, you can unlock the Double-Action Revolver.The catch here is that you have to unlock the Double-Action Revolver by playing GTA Online. Once you unlock it in Los Santos, it becomes available to use in Red Dead Redemption 2.
How to unlock the Double-Action Revolver

Check your email in GTA online and look for a message from vanderlinde@eyefind.com. It will send you to look for a chest. The chest is inscribed with Boles Overland Stagecoach Co, a logo which was first seen in a batch of Red Dead Redemption 2 screen shots.
Once you open the chest and get the Double-Action Revolver, you must complete the Headshot Challenge in freemode. This basically requires you to kill 25 players with headshots.
Now to find the Double-Action Revolver in Red Dead Redemption 2 it will become available during Chapter 1 from any Gunsmith. You can customize it to make it gold and shiny.
Note: this double-action revolver appears to be different to the High Roller Revolver.
Now you’ve unlocked that, you should grab yourself the Stone Hatchet, another weapon you unlock via GTA Online. No go read about all the best and rare weapons in Red Dead Redemption 2.