re: Sighting in question -- Need help with distance Calculat
Just posted something like this a few days ago. Should still be on here. Either way, about the best way to find out is to look at the ballistics chart for the ammo you're using. Go to the ammo manufacturer, and they'll have that information. Typically, it'll show info in 50-yard increments.
PapaD is right on. With most flat-shooting calibers, if it's sighted in dead on at 25, it'll at least be on paper at approximately 200 (depends on the bullet, which is what the ballistics charts are for). The best way to do this is to use the 25-yard rule to get it close, and then find someplace you can shoot 200 rounds to do the final adjustments. You'll want to periodically check your zero at 200, as well, just to make sure. I was posting about it because the local indoor range is only 20 yards, not that the 5 yards that close is going to make a noticeable difference (especially since I'm going to be checking it out at 200 anyway).
By the way, the actual "formula" would be either non-existant or very large if it were to be halfway accurate. There are a lot of factors. Barrel length, action type, rate of twist, type/weight of bullet, type/weight of powder, friction caliber.... and then it actually leaves the barrel. Then, you get to factor in humidity, atmospheric pressure, wind, temperature, wind resistance, etc. That's why there are so many ballistics charts, and even then, they can only give us approximate values. Ask a serious shooter in long-range (in the nature of 1000 yards) target and varmint work. They'd probably give you the best info.
