Been there.
Several years ago, I took a bad fall on loose shale and really dinged up my scope. I shot it several times and it seemed fine. But then, I shot an elk from about 150 yds. I hit way to the left and spined it. I got within 10 yds for a kill shot but I could just barely fit a bullet through the brush to her neck. It took me 4 shots to hit it in the neck, and that was from a solid rest.
Back to the range. I could put 3 or 4 inside an inch but then it would jump 4" to one side or the other. I screwed with it a long time then replaced the scope. Same thing. It took me a long time to figure that one out.
The rifle has Leupold bases & rings - the type with a dovetail on both sides of the rear ring and a cupped screw on each side to adjust windage. When I fell, part of the dovetail on the ring sheared off. I couldn't move it by hand so I couldn't feel movement but the recoil of the 300 WSM sure could shift it. It would shoot great for several rounds, then move a little. I replaced the rings and voila', it was back to a MOA rifle. I probably fired 100 rounds from the bench before I solved that one.
