Wow. As for what is bumping him, I would agree 100% that its probably neighbors. Any buck that could bump a bruiser like that is the offspring of Godzilla and an Elk, and therefore doesn't exist.
Put a cam closer to the property line, If this is as close as you can get that's good enough. If he seems to be using the same trail that's even better. If the neighboring property owner doesn't hunt setup a day in early season when he take the four wheeler or whatever out for a spin. Might just bump him into your lap.
Here is a thought as well, he might be camera shy, I had a deer a few years ago that I knew was here, I would get 2 pictures of him, he would always be looking right at camera the second picture then nothing of him for photos the rest of the year in that camera location. If I moved the camera to a new spot same thing, one set of two pictures, then he was gone from that location. It was like he associated cameras with danger and never went near them once he knew where they were. it's funny because I have had some mature deer that all but posed for the camera. He may just be avoiding the location. anyway it's a thought! hope smoke him this fall!
