I have hunted elk since '89 and taken more than my fair share of bulls. I have hunted with guys who shoot bonded bullets and what I call 'frangible' bullets. The laboratory of life has shown me how well a lung can plug a hole on the off side of an elk. They can go for miles this way. When found 2-3" of lung will hang out the skin and no blood trail. I have tracked 3 of these now. (Not mine, but others I hunt with) I have also seen 2 that poked holes in the front chest/shoulder and left blood for long distances. These bed down until we came too close then they got up and went farther away from a good extraction point. I think they have an instinct for this. Either way bonded bullets had clean passages a finger could fill. Don't get me wrong, I have seen elk drop within 50yrds of bonded bullet hits. It can be done.
Pass throughs are lost energy spent on dirt behind the animal.
A frangible bullet explodes on contact and typically produces 2-3" holes until all energy is spent and rarely exit. I have seen this with loads I shot with ballistic tips, SST's, HPBT game kings and Berger's. I have never in 18 elk had one travel more than 50yrds.
Last week I let my 12 yr old use my 7wsm. We had a spike walk out feeding at 398yards. I set him up and he placed the first bullet perfectly in the lungs. Bull stayed standing and turned around. He was sick. I had my son put another in him. Concerned I gave the wrong elevation call I told him to aim just under the line of the back. Bull was hit, but still stood there. Just as the 3rd shell was about to be squeezed off the bull bedded down. It traveled 10 yards. Upon quartering the animal we found a perfect lung shot and a 5" hole just above the shoulder under the ribs into the boiler room. It was amazing! A pool of blood was found where the last shot was made that indicated the lungs were jello on first impact.
My point is accuracy is KING when hunting the ranges I hunt. But knock down is a close second. I will never use bonded bullets, I am too lazy to track dead elk all over the mountain and be happy about it.
My 12 yr old has on cloud nine! First bull, proud dad!