I find it hard to believe that lest say @ 100 yards broad side that a 300 Min Mag with Nosler 180 grains on a double lung shot would not take one down? I have never been to Africa and was unaware that they tell you what to shoot. There is no way a lion can survive a well-placed 300 Win Mag shot.
There are a lot of other species that this rifle would be good on, the couple here, that a 300 Win Mag could handle easily.