Checking long-range CDS scope adjustments at short range

[pert near]

A friend of mine topped his .300 Weatherby off with a high-end Leupold Scope. He only shoots Weatherby factory ammo. The scope has the CDS feature which provided a custom elevation turret calibrated for a particular load. Weatherby publishes trajectory information for their ammo shot from their rifles with a 300 yd zero. Here is the info on the particular 165gr TTSX bullet at 3,330 fps muzzle velocity:


My friend carefully zeroed his scope at 100 yds & installed the CDS per the instructions. The only distance he has available at his range is 100 yds. His question to me was could he verify the accuracy of the CDS by shooting at 100 yds & note the bullet impact elevations by changing the CDS. For example, at 100yds, what should the POI height be with the CDS set at 500 yds?

I insisted that the only reliable way to check his rifle is to shoot at the actual distances, but it sounds like a reasonable idea to test as he searches for a gun range with suitable shooting distances. What should the POI heights be above dead-on at 100 yds with the CDS set for 200, 300, 400 & 500 yds?

TIA

 

[otisrush]

I'm not sure this is totally correct - but this is what I would tend to do........

You said he zeroed the scope on 100 and installed the CDS per Leupold's instructions. (I assume the CDS is marked in yards.).

I would dial the installed CDS for 300 yds and shoot the 100 yd target, holding the crosshair dead on on the target. Per the trajectory information you placed in your post, it seems to me the point of impact on the 100 yd target should be 2.9 inches high.

The CDS will get you set to hit a given distance (in the above test, that's 300 yds). Per Weatherby's data when that bullet is on at 300 yds its 2.9" high at 100 yds.

If it were *me* (which doesn't mean this is right - I'm literally just saying if I was in this situation) I would have confidence in the CDS if I shot 2.9" high at 100 yds with the CDS set to 300 yds.

 

[Varminterror]

So yes, dialing a bunch of clicks in a scope which tracks properly will shift the impact at 100yrds by the number of clicks dialed.

No, doing so will in not in any way confirm that number of clicks would actually correspond to actual drops at range.

 

[Bayourambler]

A friend of mine topped his .300 Weatherby off with a high-end Leupold Scope. He only shoots Weatherby factory ammo. The scope has the CDS feature which provided a custom elevation turret calibrated for a particular load. Weatherby publishes trajectory information for their ammo shot from their rifles with a 300 yd zero. Here is the info on the particular 165gr TTSX bullet at 3,330 fps muzzle velocity:

View attachment 797810
My friend carefully zeroed his scope at 100 yds & installed the CDS per the instructions. The only distance he has available at his range is 100 yds. His question to me was could he verify the accuracy of the CDS by shooting at 100 yds & note the bullet impact elevations by changing the CDS. For example, at 100yds, what should the POI height be with the CDS set at 500 yds?

I insisted that the only reliable way to check his rifle is to shoot at the actual distances, but it sounds like a reasonable idea to test as he searches for a gun range with suitable shooting distances. What should the POI heights be above dead-on at 100 yds with the CDS set for 200, 300, 400 & 500 yds?

TIA

Looks like the impact would be around 7” high at 100 if zeroed at 500 yds. But you have to realize weather and scope height will play a factor. It is all theory until it is proven on on paper! Lol

 

[243winxb]

Hornady