What job?

If the job you are talking about is killing someone, the .223 Remington is more than capable of doing that at ranges out to about 300 meters.

As a result of the Hague Convention, military ammunition is not allowed to expand on impact. In every signatory country this has been accomplished with some sort of fully jacketed round. The objective was to make war more humane by not killing the adversary, but rather inflicting a casualty that required more resources applied more urgently to remove from the battlefield than dispose of a corpse.

When you read reports from war zones of a single shot from a military rifle not killing someone, keep in mind THAT'S EXACTLY WHAT IT IS SUPPOSED TO BE DOING. For hunting and self-defense, we use soft point or hollow pointed bullets that do expand on impact and produce larger, more disabling wounds than their full metal jacket military counterparts.