Sounds like the Buck should be in the area dead. Possible also someone else located the dead Buck and took it. One time I along with my Brother and Father were hunting at LBL on a Either Sex Gun Hunt. Around 8 am 3 Does came down the Deer trail we located on the top of the Ridge. My Father who was using a Winchester Model 71 .348 Winchester shot the largest Doe. The Doe ran straight down the Ridge into a bottom. We started following the blood trail down the Ridge which was fairly steep. At the bottom the Doe then ran probably ran 50 yards in the bottom. We found where she finally dropped over dead. But this is where it gets interesting. Someone else beat us to the Doe and proceeded to drag her straight out the bottom to the Road and load her up and was gone. We did not see the ones who did this or the vehicle. We followed where she fell over dead and they started dragging her out to the Road. No other shots in the area. So it happens especially on Public Land (WMA). You are probably hunting on private land but there is others that could be there who don't care on whose property they are hunting. I hope you are able to locate your Buck.
Had the same thing happen on private land many years ago. MY Dad shot a 6 pt in the cedars about 150 yds from a public road. He waited until I got to him to start tracking and we found PLENTY of blood. It went downhill into and overgrown field full of briars and honeysuckles but we stayed on the trail. About 100 yds before we got to the road, we could see it in plain sight, a truck comes down the road and stops. Guy gets out and starts dragging my Dad's deer up the bank! My Dad takes off toward them, I stay on the blood and track it right to the ditch where they grabbed it.
He caught them before they could start the truck and leave, my Dad didnt have his gun with him, but I did. The argument that ensued was one you wouldnt want to hear I promise you that! There were 3 of them in the truck and I just took a couple steps back and unslung my rifle. I was NOT going to kill somebody over a deer, but have no doubts, I would have killed all 3 of them if they had attacked my Dad. He kept looking at me and telling me to go get the truck but I wouldnt leave him in that mess! Dad had his knife in his hand and I have ZERO doubts that if I had walked away he would have gutted at least one of them before the other 2 could have shot him. Dad finally saw that I was NOT going to leave him and after a cussing that would make a sailor blush, we let them load the deer and drive off.
He chewed my arse up one side and down the other all the way home for not leaving him when he told me to. I finally told him I wasnt leaving him there and Id have killed every MF in that truck if they had laid a hand on him. After that, he never mentioned it again.