Do you think it might have deflected off or followed the spine for a short time until actually clearing the body again.
Could have been any number of things...but that wound is certainly not what one would expect from a "bonded" bullet...
More research is obviously required...
BTW..here is another report from a different hunter with me on the same hunt...
My Bonded Shockwave experience was very similar. My load was 40gr of N110 and a 250 bonded with an HPH 24... Shot at about 40 yards, my shot entered behind the shoulder and never exited. The best I could tell it never touched the inside rib cage on the opposite side. The entrance was good sized and the internals were tore up pretty good. I gutted the hog myself in search of the mushroomed bullet.. .... nothing was found 