rezman said:
Assuming scope centerline is 1.5" above bore, 25 yard zero is very close to 200 yd zero, probably 2-2.5 inches high at 100. Of course it helps greatly to verify at the actual range you intend to shoot at.
Mensch! I'm impressed rezman. Pretty darn close to what my ballistics calculator gave (and I'm assuming you did that in your head?).
Bane,
here is the link to Winchester's data for that round. Unfortunately, it does not include a 25 yard entry. But you can take the MV and ballistic coefficient off their chart and plug it into
this gizmo to get the numbers you want.
Over on the left side of the page, click on "define your own bullet" and pump in the bullet weight and coefficient. Then use your mouse to:
- move the range marker (the long red line) to the 25 yard mark
- adjust the MV to 2820 fps
- adjust the "height of sight line" to the distance from your bore to the center of your scope
- set the "zero range" to your desired setting (probably 100 or 125 yards).
Now look at the box near the top right to read "H of traj ichs"... that is the desired height of the bullet above / below the "X" on your target at 25 yards to get it zeroed at your chosen range. In this case, it looks like you want the bullet about 0.7" low at 25 yards to be zeroed at 100 - 125 yards.
Move the range marker (the long red line) over to the 200 yard mark to see where the bullet is relative to your zero point at 100 yards. In this case, it looks like it will be about 3.4" low at 200 yards.
Playing around with this thing and watching the window of "point blank range" (bullet +/- 3" from LOS) you might decide to zero for 200 - 225 yards. To do that at 25 yards for 200 yards, you want your POI about 0.2" below POA; that will have the bullet 2" high at 100 yards and zeroed at 200 yards. Getting the bullet right on the "X" at 25 yards should have you zeroed for 225 yards and about 2.8" high at 100 yards.
Of course, as rezman says, you'll want to double check on a measured range.