Believe it or not, I've had one cup-and-core 150-grain roundnose factory bullet come apart on a doe whitetail's shoulder and fail to penetrate the chest cavity. Ever since I've used 170-grain Nosler Partitions, and they tend to put deer down pretty darn quickly, while always penetrating. This is because the front core of Partitions is a very soft lead alloy, and when combined with the round-nose it really opens nicely.
The same bullet really puts the hurt on woods deer when loaded in the .300 Savage.
