On one foggy morning, 35+ years ago, I was on a ridge, looking for mule deer.
As the fog began to lift, I spotted the silhouette of a deer on the next ridge, about 125 yards away.
As he became more visible, I could see he was a decent buck, and the silhouette was
fairly distinct, so I took a rest on a small birch, and sent a bullet his way.
He turned and calmly walked out of sight into the gully behind him. I was absolutely certain this was
a dead deer, so waited the mandatory 20 mins, and as the fog had closed in a bit again,
I wandered over to where he had been standing.
His tracks were quite visible in about 2' of snow, but.......No Hair, no blood, only his tracks
walking down into the gully. I followed his tracks for about ¾ mile. He did not bleed, nor did he show
any indications of a hit. He stopped several times (probably to check ) but his steps showed no
sign of any injury.
To this day, I have no idea how I missed that buck. It looked like a "slam-dunk", but the fact is, I
missed somehow. I was not a novice at the time either, I had hunted for at least 15 years prior.
It can happen, OP, so go back, and make the shot count.

Dave.