I have killed moose and had various good or excellent bullets stay inside as well as exit. Both have happened with Speer Grand Slams, Interlockeds, GameKings, FailSafes, Bal-Tips, and Barnes X, and Nosler Partitions.

If I knew a shot would present inside 300 yards, I'd choose the copper bullet. If I knew the shot would be beyond 300, then either of the Noslers. If it could be anything - near or far, then I'd use a Partition. They may seem like yesterday's technology, old news, etc, but the Partition is still a decent multi-purpose and very viable big game bullet.

Sometimes, the air you 'let in'matters less than the air you 'let out'.