Here is an example of me personally. This is not an example of poor shooting, or using less then top end equipment or not using the equipment correctly or not setting up for the shot correctly.
Its a simple example of me not being prepared.
Lets go back to last summer. I got a pronghorn permit but also had booked several hunts, early moose hunt in Canada, Nebraska whitetail hunt and then Canadian whitetail and mule deer hunt. Along with that the usual Montana hunting season.
That spring Dad and I headed down to Oklahoma and Texas for a good exotic game hunt. I used my 300 AX Raptor on that hunt, performed perfectly. As such, I was going to use that same rifle on the pronghorn hunt as it was "Ready to go".
Worked hard all summer to get customer rifles out. Did a little shooting but mostly with customers rifles testing them. That was alright, keeping sharp and shooting so I would be ready, the 300 was already to go anyway.......
Went on my moose hunt and got back and there was only a few days before the pronghorn hunt. Decided to go out to shoot, it was windy those days so we just went out anyway to test. Rifle shot pretty darn well, it was ready to go, I thought......
A couple days into the season, one morning we came across a small herd of pronghorn. There were around a dozen of them, one slightly above average buck. We set up on him, he was at 920 yards slightly elevated to our position but not enough to worry about at that range, shallow angle but we could get a good accurate range on him.
Settled in on the Raptor and waited as there was a doe right behind the buck I wanted to take. A few seconds later, the doe moved forward. Here rump just on the chest line of the buck, plenty of clearance.
The 240 gr SMK ripped out of the Raptor and instantly the does hind end dropped out and she went down. I set there wondering how a bullet could go through the lungs of the buck and still hit the doe in the pelvis...... Simple answer, it could not.
The shot had landed roughly 1.5 moa to the left of my aiming point. Likely clipping the hair on the bucks chest in front of his front legs and landing solidly on the hip socket of the doe. As the herd ran off, all obviously happy and healthy, I felt sick to my stomach.
Luckily, by the time we walked up the 920 yards of prairie, the doe had long since passed as all the major arteries in her rear end were totally destroyed. That really did not make me feel any better about the shot. Dad wanted to tag the doe with his buck tag which simply was not an option. My response was I took the shot and I got my goat.
Later that day, Dad took a great 15" buck at around 300 yards on some of our family ground. After we got that buck loaded up, obviously the shot earlier that morning was still bothering me. The conditions were still almost grave yard dead. So I lined up on a small target rock at the exact 920 yards and very similiar angle to the buck that morning. Ran through my pre shot proceedure just like always and let a 240 gr bullet fly. The shot landed perfectly as far as drop goes but it landed 1.5 moa to the left. Took another shot and then another. All three were well under 5" ctc and exactly in the same spot the shot earlier that morning had gone.......
We all have bad shots from time to time, that is just part of the sport, we are human and never perfect. It may be rare that it happens but we will eventually take a shot that we pull off. That was not the case here. I had not pulled the shot, I had not made a mistake in set up, I made an even worse mistake, I was simply not prepared.
I had not proven the Raptor was "Ready to go" instead relying on its performance nearly 5 months before. Obviously, it had been bumped enough to be 1.5 moa to the left.......
When I had checked the rifle just before the season opener, it was windy, you guessed it, right to left wind and while I hit where I was aiming, my estimate of the wind conditions down range was obviously incorrect. I liked what I saw and expected the rifle to be right on so I went with it........
Simple matter of over confidence and not proving the rifle set up before you need to use it. Personally, I would say that accounts for probably 50% of the missed out there for long range hunting, I would say another 25% is equipment error or misuse and the other 25% is simply humans misjudging the range or flat out pulling the shot to miss.
The second mistake I made was that I took a shot at a big game animal without proper clearnance between that target animal and other herd animals. Had I waited for that doe to clear more, I would have simply put 240 gr of lead into the hillside and still had my take and there would have still been a mature doe running the prairie. Two lessons that I was reminded of instantly and clearly.
I will say, I have missed MUCH less on long range shots then at conventional ranges. Pretty simple to understand why, equipment is much better, more time for the set up before the shot, more time to take the actual shot and taking shots at animals that are totally undisturbed and not moving.
Misses happen, if you say you have never missed, either your fibbing or you have not taken all that many long range shots. If you have never missed a shot at long range, good for you, you are one of the VERY few and if you keep doing it, you will eventually miss.
In my experience talking with hundreds of like minded hunters, When we do miss at long range, generally, its a very high percentage that we miss clean. Much higher then conventional range hunters in fact. Not exactly sure why but it works out that way. Not saying a big game animal can not be wounded long range hunting, that is silly.
My theory is that at long range, any error in range estimate, condition doping or pulling of the shot will generally result in a pretty wide flier of the shot.
At close range, these things may only result in the shot going a foot or so off, in some cases, this can be a clean miss but in many others, it could be a wounded animal that is likely already aware of you being there and reved up by the noise and excitement.
I can say, every long range miss I have had has been because of pilot error in some way and not equipment failure.
I've killed hundreds if not thousands of game animals from 10 feet to 5 miles. 
