A couple of things that are interesting is that you can still see how the number or quality bucks were steadily declining right up the point the deer populations increased in the southern tier. I am confident that is just more proof of how the habitat of the northern tier affected both the number and quality of the deer and especially the bucks.
Once again your inherent bias prevents you from seeing the forest for the trees. There are many reasons why the number of record buck decreased in the NC counties and the main reason is the population decreased from 45 DPSM in 1975 to around in 1979 and it has been reduced even more during the last 8 years.At the same time timber harvests increased 30M BF in 1979 to over 70M BF during the 80s, so there was more than enough food for the much smaller herd.
Furthermore, without knowing the age of the bucks that were entered ,your entire analysis is flawed. The number of hunters increased to about 1.3 M in the early 80's and the quality of our weapons and hunting gear resulted in higher hunting pressure which would mean fewer bucks would survive long enough to be record book bucks.
Until you can prove the size of the average 2.5+ buck increased due to ARs, all your claims and theories about ARs are irrelevant and unproven.