Last fall I shot a coyote with my .280AI and a 160NP at nearly 200 yards, the bullet hit a front shoulder and blew a softball size hole through him. That indicates to me that expansion was immediate and violent. A few days later I shot a six point bull elk with the same bullet/rifle combo and the NP completely penetrated the elk's chest leaving a quarter sized exit hole. I did a gutless method on him, so I don't know what his lungs looked like but I'll bet they were a mess as he was pretty much dead on this feet after the shot. I only use Nosler Partition because I know what to expect from them. They may not be perfect, but they satisfy me.
