I don't use many bonded bullets for deer or black bear, reason being you don't need them, any decent cup core bullet should penetrat a deer deep enough to hit the vitals, you hit the vitals its a dead deer, some folks want an exit, have no idea why. they say it leaves a better blood trail......Hogwash!! a deer hit in the lungs will blow just as much blood out of the nose/mouth after the lungs fill with blood as will leak out of the exit hole after and if the chest cavity fills with blood to above the exit hole.
best results I have came up with is to hold off the heavy shoulder bone the first 150 yards, by then the bullet has slowed down enough that it will make the trip through both shoulders.
high velocity impacts are what keeps a bullet from exiting, the higher the velocity at impact, the harder the point of impact is the less chance the bullet will exit, bonded bullets expand like any other, the bonding is the same principle that plumbers use with soldering flux, the lead sticks to the copper and stays togather, long as its still togather it may become a mass of twisted lead and copper but if its not losing weight it keeps it momentum.
Interlocks have a ring on the inside to keep the lead core from slipping in the jacket, hit something hard enough to disrupt that ring and it will separate, so stay off heavy bone till the bullet slows down, deer are not hard to kill.
RR