From a terminal ballistics standpoint, tumbling beginning within the first six inches of tissue may increase the wounding efficiency of a non-expanding bullet.
Every bullet will eventually tumble. Where the tumble commences depends on, among other things, what media it encounters, bullet shape, impact velocity, how fast it sheds speed, and how fast it is spinning. A conical bullet only travels nose-on by virtue of artificial spin-stability created by gyroscopic forces. Once artificial stability is lost, the center of mass (CM) leads the charge. If the CM is near or...