I just worked up a load for my son's 280 AI. 62.5g of IMR 7828, CCI BR2 primers, Nosler brass, 168g Berger, and MV @ 2920'/sec.
This load shoots 1 1/8" groups at 200 yards so it should be good to 800 yards. That's 4 to 5 inch groups at 800 yards, but I have learned I can't shoot that well in field conditions, so that 4 to 5 inches turns into 8 to 10 inches which should still kill deer.
I like to get my hunting rifles as close to 1/2 MOA as I can, but that's hard and I have custom rifles. If I can get 3/4 MOA I am happy and it seems to work well for my hunting. I have set a personal limit at 800 yards.
As for sighting in, I sight in at 250, then from 0 to 300 I don't have to think about it. After 300 I use the marks under the cross hairs of my scope out to about 500 then I dial. FFP so it doesn't matter the magnification power the scope is set at, just one less thing to get wrong.