SHARPSHOOTER CHALLENGE SHARPSHOOTER 3: Kill 5 Flying Birds While On A Moving Train.
The prerequisite of the Sharpshooter 3 challenge is to complete Chapter 1, and its reward is “Sharpshooter Holster Available At Any Trapper”.
You will need to jump on a train or buy a ticket to any train station. And then climb onto the roof of a wagon.
After that, wait for the train to start moving, then look for a flock of birds flying in the sky.
As soon as you see one, use the Dead Eye to mark five of them and shoot.