How much does elevation change POI

ATL

FNG
Joined
Feb 20, 2021
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75
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I assume the scope is second focal plane? A long time ago I used a 3-9x Ziess BDC reticle. I did not change the zero, but could increase or decrease the scope magnification to adjust the scale of the markings to match the trajectory.

For example, zeroed at 2000 DA the 30-06, 180 grain bullet, matched the reticle markings (200, 300, 400, etc.) at 7x. At 9000 DA I could change the magnification to 8x for the markings to match with the flatter trajectory. This is just an example I do not remember what the actual magnification setings were for certain loads or DA’s.

At the time it was a slick system. Zero at 200 yards on a tall target. Move target board out to the maximum yardage the scope has markings for (500 or 600 yards). Aim for the target with the 200 yard crosshairs and fire 3-5 rounds to obtain a group. Go down range and boldly mark the group so it can easily be seen through the scope. The group will be below your aiming point by a good amount. Go back to the rifle and adjust the magnification until the center crosshair is centered on the target, and the corresponding distance marker (500 or 600) covers the shot grouping. Whatever the scope magnification is set to is matched to that load and DA. Mark the magnification rings position with a silver sharpie. Test the other distances match up with the reticle markings as expected.

Using your ballistic solver, you can plan for other trajectories at higher or lower DA’s. Mark a tall target accordingly, line up your center zero crosshair and distance markings (500 or 600) for that trajectory and mark the magnification for that DA. When you get to camp check your zero, place the scope magnification for the matching DA, and go hunt.
 

Shraggs

WKR
Joined
Jan 24, 2014
Messages
1,627
Location
Zeeland, MI
I assume the scope is second focal plane? A long time ago I used a 3-9x Ziess BDC reticle. I did not change the zero, but could increase or decrease the scope magnification to adjust the scale of the markings to match the trajectory.

For example, zeroed at 2000 DA the 30-06, 180 grain bullet, matched the reticle markings (200, 300, 400, etc.) at 7x. At 9000 DA I could change the magnification to 8x for the markings to match with the flatter trajectory. This is just an example I do not remember what the actual magnification setings were for certain loads or DA’s.

At the time it was a slick system. Zero at 200 yards on a tall target. Move target board out to the maximum yardage the scope has markings for (500 or 600 yards). Aim for the target with the 200 yard crosshairs and fire 3-5 rounds to obtain a group. Go down range and boldly mark the group so it can easily be seen through the scope. The group will be below your aiming point by a good amount. Go back to the rifle and adjust the magnification until the center crosshair is centered on the target, and the corresponding distance marker (500 or 600) covers the shot grouping. Whatever the scope magnification is set to is matched to that load and DA. Mark the magnification rings position with a silver sharpie. Test the other distances match up with the reticle markings as expected.

Using your ballistic solver, you can plan for other trajectories at higher or lower DA’s. Mark a tall target accordingly, line up your center zero crosshair and distance markings (500 or 600) for that trajectory and mark the magnification for that DA. When you get to camp check your zero, place the scope magnification for the matching DA, and go hunt.
This is the way with bdc type reticle.

You can observe yourself - just look at target at 100 yards on max power. Note were your first hash is then reduce magnification and you’ll see the first hash appears lower.

So with increased elevation you increase magnification.

As pointed out above you need a perfect zero preferably 100 unless your scopes specificity is 200, and you have then found correct magnification for your drop hashes at your elevation. Which means you have actually shot those hash’s at distance to verify…then you’ll increase magnification at elevation to maintain bullet trajectory that matches hash’s. You don’t change your dail for a new zero at all!

If it’s a ZEISS they have an on line calculator that will get you close.

Having started longer range with one of those, I’ll echo 400 max. Past that the loss in precision isn’t wise.
 
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