The core can keep going and usually has a good wad cutter or mushroom shape to it. I have heard of instances where the bullet shed it's jacket fairly quickly but the core went on and exited. I have found large pieces of jacket near the entry but never the entire jacket. I have also had bullets caught on the offside hide and when I removed them the core fell out of the jacket. I call these controlled failure bullets, they all came from very dead deer.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli