Make a note that the sights are now set for about 300 yards.
If you want to shoot at, say, 100 yards, come down about 4 minutes.
Getting a rough zero at 25 yards is a good idea. I have seen a lot of rifles miss the entire paper at 100, so 25 is a good place to start.
Our club (Guelph) has a bench with target frames at 25, 50 and 100 yards. I have seen guys get a rough zero at 25 and then shift to 100 yards, RAISE their sights and then wonder why they missed the paper. They should have lowered their sights.
Your scope is higher above the bore than the iron sights, so a 25 yd zero is about the same as 300 yards. With irons sights, a 25 yd zero is about 225 on the drum.