I recently started carrying Hornady TAP 168 grain .308 ammo in my M-14. I wanted to conduct an informal expansion test of the round so I gathered up a stack of old newsprint approxiately 12 inches thick and taped it together. I let it soak in water for 24 hours in order for it to get really soggy. I then shot it at 25 yards with the M-14. The round exited the stack of newsprint and lodged in the bark of the tree I had it propped up against.
Here is a pic of about 4 inches in where the front of the bullet began to fragment.
Here is a pic of the rest of the round which did not fragment.
The round mushroomed out to .535" at it's smallest diameter.
The round largest measurement was .805 but it included a portion of the copper jacket.
Here is a pic of the bottom of the round.
I am very pleased with it's performance and I plan on keeping it as my carry rounds for my M-14.