An RPG is awkward and bulky, and difficult to get past Customs.
Is that the voice of experience?
It's not unusual for game scouts in places like Zimbabwe to carry AKs. And it's common knowledge that a LOT of animals - including elephant - were poached using AKs. But firing half a magazine into an elephant's side, figuring he'll die SOMETIME, isn't very sporting. And game scouts are primarily looking for rogue animals of the two-legged variety.
In his book
Mahohboh, Ron Thompson writes of using a military SLR (i.e, a FAL variant) to cull elephants. He seemed to like it, especially when going into a herd situation. The 20 round magazine allowed a very few experienced men to take out a whole herd in short order.
He also wrote of its limitations, and said that mature bull elephants - MUCH bigger than cows - were difficult targets for such a small round. He survived one encounter with an angry bull using his skill, experience, and (reading between the lines) more than a little bit of luck.
Thompson culled
thousands of elephants in Rhodesia/Zimbabwe during his career . . . since he survived to retire, I think it's safe to assume he knows something about what he's talking about.
I personally would not care to hunt elephant with a FAL.
Anyway, I see no ethical problem with using an AK, FAL, etc., to hunt appropriately-sized game where legal, as long as the hunter himself behaves ethically. (i.e, respects property, strives for humane, one-shot kills, obeys bag limits, etc.)