The tumble theory is just that...a theory. soft point bullets are designed to mushroom and do not tumble. If they did, you would not have a mushroom... I swear by boat tails, and use them in all the rifles I shoot. they are simply more accurate. I have killed deer with 22 cal boat tails, 25-06 117 btsp, .270 130 btsp, 7mm rem mag 139 btsp, 7mm mag 160 btsp, and 300 win mag 150 btsp, & 165 btsp. The deer I shot last year w/ the 22-250 55gr btsp cockroached with a shot directly to the shoulder. I've had em run w/ 270, and had em drop in their tracks. I've had em run w/ the 300, and had em cockroach in their tracks. My theory is it depends on the amount of shock the spinal cord gets from the placement of the bullet, and if it causes enough trauma to cockroach em. There are other biological issues as well, but careful inspection of the deer I have cockroached seemed to have quit a bit of contusion to the upper spine above the shoulder blades. (I shoot my deer square in the shoulder...) I hate getting intestine matter on my meat...I'd rather ruin a little chili meat than get feco coliform in my meat...