I have shot several deer through the heart or double lunged that had zero reaction. Just walk off or stand there and bleed out and fall over. Mostly with a bow or muzzeloader but a couple times with a rifle. I have many stories I could share. My brother shot one that was the craziest.
My brother shot a deer with a 140 gr accubond out of a 7MM MAG a few years ago. Maybe 40 yard shot. 10 ring, he hit the heart. Buck was following a doe. The buck hit the ground and kicked and laid still. Mid to upper 130's 8 pointer. He said he was excited, his best 8 pointer ever, deer dressed in the mid 180 lb range. The doe stood still a minute, walked back to the buck, sniffed of him, started walking off. The buck GOT UP and started following the doe just like he was before he shot. My brother centered his shoulder with the next shot, he hit the ground and stayed down. No way he would have lived, but I have always wondered if the buck could have walked far enough to make it tough or possibly lost him if he hadn't been able to get the second shot in him. I was there when he gutted him, first shot was through the heart. Deer can be tough.
I shot a nice buck many years ago with a percussion muzzleloader, open sights. 60 yard shot. My friend was standing right beside me. We were scouting, middle of the day, muzzleloader, and my friend looked up and saw the buck just staring at us. Buck was in full rut. His main beams would touch at the ends but one is just inside the other. Only a 110" deer, 8 ptr, my friend did not want to shoot him, I did. I shot really fast, like the moment the butt of the gun touched my shoulder. The deer never reacted, nothing, just walked off. No kick, no run, no flinch, no jump. Just walked off. It was quiet an dry and deep leaves. He got out of sight quick, we could hear him walking, my friend said if I knew you were "blanking" going to miss, I would have shot him. I am thinking I shot before I was on him, but I remembered seeing what I wanted to see through the open sights. We heard a crash. Deer walked about 80 yards. I shot him through the heart. There was zero reaction. Like I said deer can be tough.
I killed a nice buck a 7MM STW at about 60 yards many years ago. Dressed out 191 lbs. 140 gr accubond that chronograph at over 3500 fps. Kind of same as percussion shot above. I threw gun to shoulder and shot after yelling and getting him to stop. Right after I shot, he looked like a bull in a bullfight, he trotted a few steps and was looking around like he wanted to fight something. I thought there was no way I missed. I worked the bolt as fast as I could and was going to shoot him again, when he started wobbling and fell dead. Double lunged, exit hole as big as a softball.
I shot a nice buck in KY at 40 feet with a 30/30, he trotted a few steps, stopped, saw a doe, put his head down in doe chase mode and took off trotting, I shot him in the center of the shoulder with the next shot, he still kept on going for about 20 yards and died.
One deer I lost with a percussion muzzleloader, I had made a stalk, got real close and he took off. He was running full speed. I shot him at about 60 yards, he rolled like a rabbit, 2 or 3 tumbles head over butt. When finished rolling, his antlers were kind of stuck in the ground, feet sticking straight up for a few second before feet fell over sideways, nice buck for sure. Laid still, I started reloading to walk up and make sure he was dead. He got up, and for sure hobbling, got out of sight before I could get reloaded. Several friends helped me look for the rest of the day. Never saw that buck again.
