Gyroscopic stability has zero to do with what happens in the terminal phase. That metric is set forth in context of flight thru air which has very low density. When the bullet strikes flesh/bone the density is much higher and the overturning moments are immense. Bullet form is far more important in my experience. Round noses serve a purpose, as do those bullets with little if any exposed lead on the nose.
Case in point:
.22 CB Short
Some light reading if interested.
http://www.rathcoombe.net/sci-tech/ballistics/wounding.html