I like your load velocities from 80.9-81.5 & 82.1-83.0. You've hit a couple of velocity flat spots/nodes. Most of the nodes run 0.4-0.8 gr in powder and yield not much difference in velocity. I'd try loading up those 2 load ranges I listed above, but in 0.2 gr increments. Then pick the lowest velocity spread between those 2 and load up a charge in the middle. Shoot 5 more at that load to see what your ES is. Of course you want single digit ES, but anything 25 or less is good and it will be a very stable load. I'd load 4 more at the same time and see how it groups. If the groups aren't as tight as you'd like, then play a little with seating depth to dial it in. The 6.5 Guys have a great video and write up on doing load development this way. It's the only way I do it now. I wouldn't be surprised if Mike338 is correct and 81.3 ends up being your load
Question? Did you hit any pressure signs at 83.0gr? If not, you may have even a higher node. Once you find max, drop down 1.5 gr and work up from there in 0.2 gr increments like I stated above