Duffy, I was using 150gr. Core-Loct's in 7MM RM on both bucks! On the recovered bullet (shoulder shot,) the bullet did not retain much weight, but what was left of it had not expanded much. The other, (double lung) the exit was no larger than the entrance! I am suspecting it may have just been a bad box. Maybe the lead and/or jacket may have been harder than it should have been. I've not had this problem before.
Anyway, two holes should be more than twice as good for tracking!