I did quite a bit of 1,000 yard shooting this summer with both a .300 Win Mag Sendero, and a Remington R5 Milspec in .308. Put hundreds of rounds through these and a couple ARs as well. Reloaded for them, would crank the scopes down to 200 yard zeros at times, back up to 1,000. So...deer hunting starts - set the Sendero at a 200 zero, and grab a Savage 300 WM out of the safe (a little lighter in case of pushing woods, etc) - didn't bother to check the zero (also switched to 180 gr Federal premium ammo with a Nosler Accubond bullet) - figured it was close enough for hunting - sighted in last year. Big mistake.
One morning - left the box stand, hadn't seen any deer but spotted a coyote at 100 yards, just walking along. Took a shot with the Savage - expecting good results - Missed!! One more shot as she jumped into the woods - missed again!! What the heck?? Went and set up a target at 100 yards - 6 inches high!! Probably parted the fur on her back. My son could not believe as meticulous about reloading and shooting as I am, that I would not check the rifle and ammo....... Couldn't disagree with him. Not sure how it could be 6 inches high, but it was... A good learning experience - may not have too many shots at a coyote like that one!!
Just had something similar happen. I shot at a 185 class mule deer at 825yards, a very do able shot for me. The bullet missed and hit about 36 inches to his right. I did not know what to think and thought it was shooter error. Placed my rifle on the 4 wheeler and noticed the windage knob was set a 5 MOA to the right. Checked the numbers for the distance I had just shot and found it was shooting 38" to the right. I learned a very big lesson, check your equipment.
I shot a good mulie the next day at 600 yards, but he was no where near as nice as the one I missed.
Well I will tell on myself this year while we are at it, we wasnt seeing any elk one day so my buddies and I were all standing around the truck and I ranged a rock face at 1240 meters, dialed in my scope on my 338-378 and was getting to let one fly, all of a sudden a war broke out about a mile dwn the road so we all jumped in trucks and hauled dwn the road, someone had jumped a big herd of elk, by the time we got there they were gone so went back to the spot where I was going to shoot at the rock and was standing there and a bull came by at 150 yds, I pulled up and shot and wow I was way high and the bull ran off, opps I had forgot to reset to zero, LOL oh well isnt that where hunting camp stories come from,