akbound

I would be certain to zero the rifle at 100 yds. (Depending on what you are expecting for a " hunting Point Blank Range (PBR)" the range at which you want your bullet to travel no more than 3" to 5" above or below your point of aim.) With a load that you quoted your final zero will probably end up being in the vicinity of 2.5" high at 100 yards. Which will most probably put you within that 6" to 8" circle out to the maximum range of your PBR. But like the others have already said, " shoot at those ranges to confirm it" .

I also shoot my rifles first at 25 yards when I start zeroing. I generally want the strike of my round to be close at 25...then I move to 100 for a " zero" . Depending if I am sighting in open sights, aperature sights, and or telescopic sights, determines where I would like my rounds to impact at 25 yards. More importantly, " how high above the line of the bore is the line of sight?" You didn' t say what type of sights you were using, or how high above the bore line your sights are. What I am inclined to believe is that you are probably using a telescopic sight, (and with a difference of zero at 25 yards and a foot high at 200 yards), I would suspect it might be a scope with 40mm or bigger objective and set in either medium or high rings. (Or even a somewhat smaller or larger objective lens but still set in higher rings.) If this is the case....your line of sight would be relatively high above the bore line. Which, when zeroed at 25 yards, requires that the axis of the bore line in relationship to the sight line is tilted quite high. Think of two lines, parallel to each other. In order to bring these two together at 25 yards requires that you significantly tilt the bore line " tilting it up" in relationship to the line of sight. Which would explain why the strike of the round is so high at 200 yards in relationship to the point of aim.

Suffice it to say when zeroing a scoped rifle at 25 yards I usually try to get the bullets to impact centered for windage and 3" or 4" low at 25 yards. Then when I move to 100 yard range I find the zero closer to " my zero" . Depending on cartridge and sight configuration I will zero my rifle either " dead on" (in the case of a pistol caliber carbine or dangerous game rifle), to as much as 2" to 3" high at 100 yards. But even then if you have access to a longer range confirm your bullet strike at 200 and even 300 yards (or more) if you intend to actually shoot at those ranges.

From the moment your bullet leaves the bore it starts to drop. We compensate for this by slightly tilting the axis of the bore up when we zero. This causes the flight of the bullet which actually starts under the line of sight to cross above the line of sight at a nearer range it continues to climb until it reaches its zenith, (or apex), and then falls back below the line of sight. Meaning it intersect the line of sight again somewhere downrange. Depending on the ballistics of your cartridge, (and all the external ballistics), and your sighting equipment determines how best to sight it. Most people make it simple by sighting their scoped, modern rifles, to strike between 2" to 3" high at 100 yards which usually gives them a " hunting zero" to something between 200 to 300 yards without too much concern about shooting over or under deer sized game. Suffice it to say it is both as " simple" or as " complicated" as you' d like to make it. (Keep it simple.....if you can!)