back in 2000 before it was the craze, i was pretty good with my 50 bmg. i had an antelope tag that year and figured shooting the antelope with the 50 would be pretty cool. i was sighted zero at 800 yards with surplus military ammo, and closer to 900 with some FN incendiary ammo. during the summer preceding the antelope hunt i fired around 700 rounds through the rifle at ranges from 600 to 1500 yards, a softball sized rock at 800 was not safe. my buddy that spotted for me while practicing went with me to hunt. i believed his calling of all my shots.
after shooting at a few antelope and not putting one down, i finally saw one of the bullets blow hair off one. the range was 900 yards, the first bullet just grazed the top of the back removing hair. while the animal was still standing there, i put another bullet 2" to the side of the first one, then the animal took off. i knew i had hit it, so i followed it as it ran with the herd. while running at an unknown distance (later ranged to be 1280 yards), i fired again. this time the animal peeled out of the herd and laid down. i closed the gap to about 150 yards and then fired again, this time aiming about 4.5 feet low. that bullet killed the animal with the bullet going through the neck.
i still have the hide, the first two bullets took a channel of hair out off the back directly above the shoulder, the third punched the animal at the back of the rib cage damaging the liver.
in the weeks after the hunt, i came to the realization that though my spotter had called misses on 3 or 4 occasions, that i had probably hit all of them. he called misses after seeing the bullet hit the ground hundreds of yards behind the animal. despite the bullet being 1/2" in diameter and weighing about 1/10 of a pound, no energy was imparted to the animal.
at the longer distances, there is a great likelihood of poor bullet performance, poor shot placement, and in my case, a great possibility of failure to determine a hit. the great distance also makes it difficult to immediately track the animal and finish it.
i thought i was quite a "hunter", and quite capable with my equipment. after that hunt, i have never tried to kill an animal over 600 yards. it IS unethical, even if you can do it.
i have also heard of many stories of the BOW guys and others losing numerous animals while "hunting". everyone will eventually lose an animal, but a hunter's responsibility is to quickly and humanely kill their quarry. to achieve that end, a hunter should use his abilities to increase his odds of a quick clean kill. that includes actually hunting (getting close enough that misses are almost non-existent), and being as proficient as possible with their tools.