What did your bullet look like? (you said you found it)
Core lokt usually perform pretty well, though not really considered a premium bullet.
There are also two schools of thought out there...1 says they want a small entry hole, and larger exit hole on every shot. Others say they DON'T want it to exit...to stop just prior so as to expend all energy IN the animal. I personally prefer two holes
I like better blood trails in case that your shot is not as good as it needed to be.