To obtain this achievement, you must shoot down Caragor bait; which is effectively a large hanging animal carcass. These are found hanging from Uruk structures and around the strongholds. You can spot them easily by using your ability mode (
), as they glow green.
WARNING - The attracted Caragors are
NOT your friends; they will attack you on sight just as they will any enemies in the area.
What seems to be confusing is that I shot down one slab of meat by the black gate and it attracted five Caragors and the achievement unlocked. Whether this is a glitch or not I do not know.
Forgotten how to shoot?
HOLD to aim and
PRESS to shoot.