Here is the full list of all 21 Western 1849 Reloaded achievements.
Kill 25 bandits in Rage Mode
Fire 5000 bullets
Complete very hard difficulty
Knock down 250 hats from bandits
Shoot 50 canns
Kill 2000 Bandits
Perform 500 perfect reloads
Kill 100 bandits using dynamite
Have 2 items equipped in the backpack
Complete hard difficulty
Perform a 15 kill streak
Perform 50 Perfect Reloads in one game
Perform 500 head shots
Complete medium difficulty
Upgrade your equipment 3 times
Fire 100 bullets in one game
Perform 50 headshots in one game
Kill 6 bandits with one clip
Complete easy difficulty
Complete 3 waves in a row without losing any health
Complete insane difficulty