Please note this is how I do it and involves my opinions only. Take it for what it's worth.
Let's say that I'm starting out with a new big game hunting rifle and no idea how it will handle my hand loads.
I will decide which Nosler Partition bullet will probably fit my needs the best because I don't hunt big game with anything else. Using a bullet of equal weight (but not the cost!) I will try several different powders that are the most likely to give me the highest velocity I can get. Once max velocity is established (using a chrono), I will load up 3 round batches of the good stuff (read = $$$) with the Partitions and the different powders and shoot these off the bench at 100 yards.
Ok, a little pause here. I am at a big advantage over most guys in that my 100y range is in my back yard. My chrono is usually set up right outside my basement sliding glass door, literally 20' from my loading bench. Of course it makes the entire process a whole lot easier for me. But then, I planned it that way.
So, 3 round groups. Anything that looks like it has potential will get further load development, maybe drop the charge by 0.2 gr and see if there is any improvement. If yes, drop a couple more tenths and check again. Vary the seating depth a bit (always seating deeper because I always start out at max magazine length).
If I can't find a load that shoots well with this set up, I might try some other powders but if I don't see any potential, I sell the rifle (which I have only had to do a couple of times, just because they didn't like the Partitions... it happens). If I can get a nice group out of the rifle, I will try a 5 shot group. If things go well, I will clean the rifle down to bare metal, fire 4 or five foulers (back to the cheap bullets for this task) then run a patch of synthetic oil thru the bore, just as I always do if not cleaning the bore, such as when hunting. While I've never taped my barrels, it's a very good idea and today I would do this.
Now I wait for whatever conditions I expect I'll be hunting in. Living in the State of Misery (MO - it really isn't quite that bad but almost!), you'll get just about everything eventually. I'll put the rifle (in it's case) in the garage overnight, along with the ammo, and when conditions are as bad as I think they'll get, I go out and shoot a cold bore shot. Target is brought in and marked and the barrel gets one pass with some oil on a patch (not soaked and dripping, just damp). Then it's a matter of waiting at least a couple of hours and if conditions remain the same, shoot another round. I do this a third time so I can hopefully eliminate any loose trigger finger screwups. If the group is still centered where I want, oh happy day we're almost done! If not, adjustments must be made and cross checked (conditions seldom last long enough to do this in one day here, as the weather changes quickly and often dramatically... and somehow, it always seems to get worse!). Once all that is done, then I'll try (again in the same conditions if possible) a two or 3 shot group, just to make sure everything stays in an actual group, instead of playing "shotgun!" I will also test in other conditions, of course, although with my luck, shooting in the worst conditions usually matches what actually happens! I also use a ballistics computer to set up a point blank range chart - *based on the velocity and accuracy of that particular round!*
If you set up your AR or any other rifle to shoot at some phantom point blank range (36 yards is the most often quoted for the AR), you're doing it wrong! Without knowing the actual velocity of the ammo you're using that 36 yard target is mostly a guesstimation! There are numerous point blank range calculators online but like anything else, garbage in, garbage out!
So even with my range being close at hand this process can take time, which being retired I have lots of! I know the average hunter probably won't take this much time to get his/her rifle dialed in but in the long run, it can make for some serious confidence when you're up to your knees in snow, laying down in it and shooting that big bull or buck and knowing that your bullet is going exactly where you want it to go and that it will it's job perfectly when it gets there. And I like that!
I always do my best to get as close as I can to a big game animal and admittedly, the majority of my shots are pretty close. While I never plan on taking the longest range shot I can find, I like to have the ability to do so if necessary, so I practice that, too. So far the longest shot I've ever taken on a game animal is 700 yards, totally unplanned and unprepared for (someone elses wounded antelope... it's a really long story I won't bore you with! Aren't you glad?!). Please note, jack rabbits are not big game animals! Oh the stories....!!!
Cheers,
crkckr