How much elevation travel does the 1.5" scope height use up?

[ASH556]

I'm not sure if the wording is clear, but here's the idea:

When shooting a scope on a long range bolt gun, guys typically use a 20MOA or 40MOA base so that they cheat enough adjustment into zero so they have enough turret travel to get them to longer ranges. Bolt gun optics are mounted much closer to the bore than AR optics.

My question is, how much of your elevation do you use up mounting a scope 1.5" above the receiver (like in a Larue mount) on an AR15? I'm planning to mount a Zeiss Conquest 3-9x40 on my AR. Zeiss says the scope has 64"/100yds of elevation adjustment. That's 32" up and 32" down from mechanical center. How many inches of adjustment am I likely to have after mounting on an AR15 flattop?

Thanks!

[BobinNC]

I'm not sure if the wording is clear, but here's the idea:

When shooting a scope on a long range bolt gun, guys typically use a 20MOA or 40MOA base so that they cheat enough adjustment into zero so they have enough turret travel to get them to longer ranges. Bolt gun optics are mounted much closer to the bore than AR optics.

My question is, how much of your elevation do you use up mounting a scope 1.5" above the receiver (like in a Larue mount) on an AR15? I'm planning to mount a Zeiss Conquest 3-9x40 on my AR. Zeiss says the scope has 64"/100yds of elevation adjustment. That's 32" up and 32" down from mechanical center. How many inches of adjustment am I likely to have after mounting on an AR15 flattop?

Thanks!

Not sure it is possible to answer your question, as there are other variables. But generally speaking raising the sight height from 1.5" to 2.5" has a positive impact (requiring less adjustment to reach a particular range).

A better question to ask yourself is: What load am I planning on using and how far do I want to be able to shoot it? Then finding the correct scope and mount options that fit that need....

I do it by building a JBM Ballistics table for the load I'm planning and see what adjustments are required to reach range.

For example: Using a 77 Gr SMK @ 2750 FPS 2.5" sight height and 32" of scope travel will get you to 800 yds (+-25 yds) or so before running out of travel.

So if you already own that scope and want to shoot that particular load further, then you would need a canted base (20 MOA). Or if buying new just select a different scope scope in the same price range that has more adjustment.

This all assumes the scope, rings, base, rail top and barrel are all in optimum alignment. Anything that is out of alignment will use up adjustment, quickly, and no way to predict before buying...

[arizona98tj]

I'm not sure if the wording is clear, but here's the idea:

When shooting a scope on a long range bolt gun, guys typically use a 20MOA or 40MOA base so that they cheat enough adjustment into zero so they have enough turret travel to get them to longer ranges. Bolt gun optics are mounted much closer to the bore than AR optics.

My question is, how much of your elevation do you use up mounting a scope 1.5" above the receiver (like in a Larue mount) on an AR15? I'm planning to mount a Zeiss Conquest 3-9x40 on my AR. Zeiss says the scope has 64"/100yds of elevation adjustment. That's 32" up and 32" down from mechanical center. How many inches of adjustment am I likely to have after mounting on an AR15 flattop?

Thanks!

Here is an idea you could try. Using one of the external ballistic apps, accurately enter your information for two different sight heights (the center line of the optic above the center line of the bore). Keeping all other variables the same, run the numbers for each sigh height and see how much of a difference it really does make. I use the Shooter application but there are others that are free and I'm sure those would be more than adequate to give you the facts you are looking for.

[ronald]

Just mounting your scope 1.5" high will not affect how much travel you have. If it does it will very little and it will not make any difference. But if you want to know for sure, zero your scope on your rifle and then dial your scope until it stops and count how many MOA you dialed. If you dont think that 32MOA is enough for your long range shooting, add a 20MOA mount than you will get aprox 52MOA of travel.