David,
Good shooting, and you are off to a good start. I would like to suggest a couple of things. First get some cheap ammo ( doesn't matter if store bought, or if you roll your own. ) Shoot the gun, and get started getting used to it, and by that I mean the trigger, and hold,, Get some muscle memory going here, while you "BREAK IN" the rifle. Keep track of the shots fired so that when groups start to close, you can take notice and then go back to your "Hunting Load" development. Since you now have an idea of the COAL and you are closing in on the node,,,, Chronograph the other loads and do a little variety so that even with cheaper ammo you are learning and developing your information. Then you can go back to the 150 grain or even change and go to your 165-168 Barnes. By shooting the Dots or circles you are limiting yourself some. Best to get some targets with squares when developing accuracy loads. This way, the scope Cross Hairs, can be lined up to bump the Horizontal line and the Vertical line. That way you absolutely have the closest possible point of being the same each time. Benchrest shooters do this. Of course they do not care if the POA and the POI are the same. But by following their example in this, You will know more precisely what your loads are capable of.
Doesn't matter which corner you choose.
Keep this going, and try to shoot some groups with a fouled barrel. First off, when the Hunting Season starts, It has been known to be the last time a person cleans their barrel, till the season is over. Unless rain or something else cause the need for attention. Here Again Benchrest shooters always fire a fouling shot, then start on the group. Try all these things while you are breaking in the barrel, and getting more trigger time with your gun. Then as you go back to your "Hunting Load" development, you can refer back to your notes in your LOG BOOK and notice if you need a fouling shot, or just what a cold bore shot is going to do, or how it is going to react.
I am looking forward to the progress on this.
Charles