Okay, a few points to think about. I have a 100-yard backstop at my house, and just a few yards away from the house is a shooting table for a 500-yard range.
I'be been messing with Ol' Pet for over thirty years, shooting proably around or over 4,000 rounds through. Lots of plinkers; not bunches of stuff hotter than USGI.
So. I sight in for two inches high at 100 yards, which is nominally dead on at 100 yards with the Sierra 150-grain SPBT. The book sez dead on at 200, 6" low at 300, 21" to 22" low at 400 and around 45" or so low at 500.
I go out the first time for 500. I guesstimate four feet above the center of the 22"-diameter plate, and hold a foot off to the side for the wind. My first hit was 6" low at 5:30. My second hit was 1" low at 6PM. "Time to quit," I sez.
So I load up some 165-grain and 180-grain Sierra BTs. I adjust the scope for 500. With the remaining 165s, I get two four-shot four-inch groups. With the 180s, I call two flyers out of a ten-shot string and get a six-inch group.
The point of this is, first, it's off a table. Second, it's a known distance. IOW, I darned sure ought to be able to hit a 22" target under those conditions.
Now move to the field, without a laser range finder. You might be a flatlander in canyon country where distances are VERY deceiving. And you're limited to a hasty rest. Whole different ball game. I'm not gonna guesstimate the difference between 400 and 500 yards in canyon country. I did that once, and missed eight times before the cooperative buck moved some 150 yards toward me. (His mistake, which didn't keep me from a serious case of restrospective, "Art, you were stoopid!".
)
If you haven't spent a bunch of time in the field, looking at lots of game at all manner of distances over a bunch of years, control yourself about how far off you can reliably hit the animal for a clean, ethical kill.
I dunno. Set paper plates out every 50 yards to 500. Guesstimate holdover and windage, and practice a bunch.
THEN talk about 500.
Art