Without heavy bone contact, it's not at all uncommon for a whitetail to make the 100 yard mark following a heart/lung hit.
Also, if there was a lack of heavy bone contact, that could explain the small exit hole. What did the contents of the chest cavity look like??
It doesn't sound like you really had too much of a bullet "failure". Just one of them things. I know from much firsthand experience that the .308 Win and the old Winchester Silvertip (we used 180's) is one of the finest whitetail combo's that ever existed.
Also, if there was a lack of heavy bone contact, that could explain the small exit hole. What did the contents of the chest cavity look like??
It doesn't sound like you really had too much of a bullet "failure". Just one of them things. I know from much firsthand experience that the .308 Win and the old Winchester Silvertip (we used 180's) is one of the finest whitetail combo's that ever existed.