Cabelas Safari

The Lions you are looking for are directly to your left from the starting area. Go up the little hill and look towards the water. They will both be there. Just equip the .600 and blow them away.

Bagging the trophy animals on expert is not to big of a challenge except for the fact that there is no radar. Although there is no radar the three rings around the target reticule will slowly glow red as you near the game animal, and will flash if the animal sees you (which in the case for these animals they will charge). Just kill the trophy and the achievement will be yours!