Range Report Need help with Tall Target Test

[bassmaster07]

The test in question:
100yards
Tikka CTR in Bravo
6.5 Creedmoor

SCOPE: Athlon ETR

Started at 1mil high, went to 9mil up. Down to 5 mil then 1 mil right/left. Was not happy with what I saw. Then did the next 10, started at 9mil up in case hot barrel was stringing up (did not think this the case but now I know it is not) and came all the way down to 0.

Typically I am probably grouping at 100 just over .75” with very controlled groups. Groups from yesterday day (same day as y’all target)

data from the day

Do I have a tracking error? It sure seems that way to me. Reticle lines up perfectly with the target. Left right seems to be spot on when dialing up. It just seems like it has too much travel the higher I dial.

I know there is a way to figure this out and adjust it in calculators but I am going to need some help.

 

[Sig Marine]

You have a PM

 

[Sig Marine]

Why you perform this test - To confirm elevation shift and vertical is mechanically correct and make any necessary corrections to compensate for any deviation in your ballistics program using the correction factor

What is elevation shift - Elevation shift is the amount of travel your POI has at a given distance when the turrets are dialed to a specific elevation or windage

To determine your elevation shift - ELEVATION SHIFT = DIALED ELEVATION x DISTANCE x CONSTANT
Dialed elevation - what you dial on your turrets
Distance is measured from your target TO YOUR TURRETS and MUST BE ACCURATE
Constants: MIL = .03599, MOA = .01047

Example 1 – dialed elevation is U10.0 MIL or U36.0 MOA at a distance of 100 yards

U10.0 MIL (dialed elev) x 100 (distance) x .03599 (constant) = 35.99” or 36”

U36.0 MOA x 100 x .01047 = 37.69” or 37 ¾” small

Example 2 – dialed elevation is U10.0 MIL or U36.0 MOA at distance of 102 yards

U10.0 MIL x 102 x .03599 = 36.7098 or 36 ¾” small

U36.0 MOA x 102 x .01047 = 38.4458 or 38 ½” small

As you can see from the above examples, your target/turret distance MUST BE ACCURATE, being off just a couple of yards makes a big difference and will help you avoid entering a number in your correction factor that is not representative of your scope's true travel

To calculate your Correction Factor, you divide your expected POI shift by your actual POI shift. This is the number you enter in your ballistic program

 

[Jabot]

Measure your distance with a tape measure .I got a 300 foot one .
Shoot your rero, dial up "I run mils" 10 mills 36 inches. My vortex is spot on

 

[Gil P.]

Did you ever redo the test?
What method did you use to measure your 100 yard distance the first time?

Try a measuring tape like jabot mentioned. They are only about $30 at home depot.

 

[bassmaster07]

Have not re shot it. It was at a friends private range. He said it was 100 yards. Checked with 100’ tape long ago and it was pretty much right on. Checked on day of test with range finder. 100.3 and 100.5.

going buy a tape a redo it.

 

[Gil P.]

Good luck, let us know how it goes.
What scope are you using?

 

[bassmaster07]

Good luck, let us know how it goes.
What scope are you using?

Using Athlon ETR.

planning to build a scope mount so I can test with out the shooter error. I think the trend hi was me and not the scope. If it is the scope it would be the first one that I have heard did not track properly.

 

[akxx]

Agreed. Those ETRs from what I have heard track very very well. Please keep us updated.

 

[bassmaster07]

Work has gotten busy again so probably a little while before I test? Will update when I do.

 

[mudpig]

Here is the one I built. My ERT tracks perfectly, but you do have to be exact with your yardage

 

[seansmd]

the other thing I will add is your target with the groups, while the groups are consistent in size their elevation and lateral position seem to change. I am not sure if this is different ammo.

You may have contribution of fundamentals of how you are building your position and its affect on your zero position. the rig above removing the shooter error would eliminate this for sure.

 

[Dthomas3523]

Don’t do tall target tests with groups. Not much sense in adding a human factor into it.

Measure distance exactly and perform the test visually with the optic locked down or weighted down, level and plumb.

You’ll know immediately if you have an error and can go from there.

 

[hdguy328]

Here is a worksheet for the tall target test from Applied Ballistics. This may help you.