I ran a quick calculation on iSnipe (great app, by the way)...
I used Nosler's 180gr Accubond factory round. It shows 237 inches of drop at 1000yds (with the rifle zeroed at 100yds). It's showing 47 inches of drop at 550yds (same zero).
If he zeroed his scope at 500yds, he'd have 163 inches of drop at 1000yds, and 45 inches of drop at 725yds.
He would have to have his scope zeroed at 900yds in order to have only 44 inches of drop at 1000. Either he's outright lying, or he doesn't know how far 1000yds is.
I won't even get into the fact that off-the-shelf hunting rifles and scope setups will not even come close to remotely being able to maybe consistently hit a target at 1000yds... The skill of the shooter notwithstanding.