I had an experience almost thirty years ago that still has me puzzled. I shot a nice whitetail buck in the lower chest with a 170 grain Winchester Power Point slug from an 8mm at twenty yards. It ran off without leaving any blood trail and died about 100 yards away. When I examined it the exit hole had an acorn just barely protruding. I can only assume that the bullet hit an acorn the deer was in the process of swallowing and drove it almost completely through the deer. The acorn was intact and only had a slight mark on one side. Anybody else ever have something like this happen or have any guesses?

I have seen a bullet suck organ, intestine and other tissue into exit holes and plug it right up. See it all the time when using shotgun slugs on deer.
In your case, the bullet traveled close enough to the acorn so that it was sucked along behind the bullet and lodged in the exit.

I think Dave has your answer. I just wanted to bring this thread to the top...

Dan

The acorn would have been destroyed if the bullet had hit it. Apparently the buck did not chew on the acorn any before swallowing it and the hyper speed of the exiting bullet caused the acorn to be sucked into the hole.

That was pretty much what I thought burt I was curious if anyone else had ever experienced anything similar.