Open Country

when you unlock the weapon range from completing story missions. travel there, activate a chalkboard pick any of the 3 modes (practise just continues until you pick up another weapon or activate the chalk board) and the gold/yellow crown will appear from time to time, the targets all move and show in a pattern. Some crowns appear next to the red and white exclamation sign.

Doing the other weapon range achievements Perfectionist and Diligent will help to do this. I personally recommend to use one of the rifles if you plan to aim for this achievement directly.