Using a sniper rifle, kill 2 targets with a single shot
Far Cry 4 TWO BIRDS – Achievement / Trophy Guide
Travel to Shanath Training Ground at (X: 255 Y: 543) and bring any Sniper Rifle. You will see 2 guards standing next to each other near the cages. They stand there for a long time and probably won’t move at all. If you jump on the rock in the video you will have a clear shot at both of them. Aim at their heads and take them out with one bullet.