I watched rangers culling elephants with AR-15s in Tanzania. It all boils down to being able to shoot the rifle that you have, and knowing its capabilities and its limitations.
For North American sport hunters, the priority should be making a clean kill--not wounding animals to death. This means passing on shots that are marginal or low percentage, regardless of how few opportunities you have had or how little time you have left to hunt.
Culling, especially for population reduction or removing problem animals, is something entirely different.
