as im learning more about how these things work it seems some (not all) lead bullets do cause more damage with a bigger wound channel, so one should not necessarily expect the animals reaction to be identical. Sounds like it could be an issue in some cases, although Ive never personally seen a situation where I think it would have mattered. I have never had a non-expansion of a copper bullet Or any issue that I think could be a result of bullet performance. what I have experienced is that there is significantly less meat loss with copper, which is very important to me and is the main reason I choose to hunt with it. Below is the sum of my copper experience on live critters.
7mm08 120gr ttsx 195yards, impact velocity about 2450 antelope— high lung hit, bqang flop, 2” exit wound.
7mm08 120gr ttsx 219 yds, impact velocity about 2400 fps, antelope, frontal shot at base of neck, bang flop. Lots of internal damage, exit out rear crease in front of ham.
7mm08 120gr ttsx 168 yards, impact. Velocity about 2550, double lungs from slightly above, antelope. 2” exit wound, ran 60 yards, stood there for 15 seconds or so and tipped over, kicked for a while and took a second shot. It was dead and still fighting, but. Tons of blood so would have been an easy trail.
3006 168 gr ttsx, 60 yards, impact velocity 2650 fps, elk heart shot took out the top of the heart, exited in off side crease. Humped and bucked, ran 10 yards and stopped for a second heart shot, and tipped over backwards and never moved again. Second bullet entrance was 2” from first, but lodged in the off-side shoulder ball joint, perfectly expanded with 96% weight retention. 1st bullet exit hole was about 3/4", internal damage (torn tissue, bloodshot) to heart and lungs extending about 2" around the hole.
3006 168gr ttsx, 110 yards, impact velocity about 2590, whitetail high broadside hit. Dropped on the spot, but was kicking himself in circles. Finished with one shot through breast bone and out spine. Bullet passed through vertebrae and was barely protruding through hide on the outside of the spine, perfectly mushroomed with 95% weight retention.
6.5mb 120 grain trophy copper, 80 yards, impact velocity about 2550, antelope. this was a second shot on an animal that had been hit badly—Antelope rear end was down but front end still up, this shot was hard quartering-to in front of the near shoulder and low, and exiting out high in the rear quarter, took out heart. heart was exploded, couldnt salvage any of it. Exit wound from second shot caused some meat damage to the rear of one backstrap. Roughly a 1.5” exit with an inch or so of damaged meat around it.
also edit-- one I forgot: 30caliber trophy copper, approximately 200 yards, impact velocity approximately 2575fps, pretty big bull elk broadside heart shot. Bull stood up out of bed, was hit, reared on his hind legs and toppled over backward. Full pass through, barely grazed the heart. exit wound was maybe 1"
these are the two copper bullets Ive recovered, as described above--both are 168gr fired from a 30-06. The darker colored one from the elk, the other from the deer.