Rifle Scopes Scope Tracking Test / Tall Target Test Athlon Cronus BTR

[USMC 308]

Have not done one of these in many years. My last time was with a top tier scope manufacturer back in 2003 or 04....and it did not go well. Rob 01 can attest.

After reading some feedback in another thread, I decided it was time to do one today. Now I assumed that in today's day and age, with the high degree of precision in the computer integrated machinery, a failed test should not be happening, nor should it be acceptable to the consumer.

Rifle : 6.5 CM Bergara Premier LRP rebarreled with a 27" Hawk Hill M40/24 contour 1/8
Scope : Athlon Cronus BTR 4.5-29x56 Mil/Mil
Ammunition : Hornady Match 140gr ELD Match (Factory)
Laser Rangefinder : Sig Kilo 2200 MR

Light wind, 90 degree day in Central Texas

Made Tall Target according to directions, placing a orange dot on zero and 10 mil (36 inch) marks.

I ran 2 separate tests using new marks on the target. Test Target 1 was 3 rounds at each setting (zero and 10 mils). Test Target 2 was 2 rounds at each setting (zero and 10 mils). I dialed up and down 10 mils after each shot.

Lazed target, took distance from turret to target. Here's where the fun begins. On a dark target, a reading of 102.6 yards was consistently recorded. On my white target, a reading of 102.0 was consistently recorded. I did not have access to a 300 ft tape measurer so I'll do 2 sets of calculations.

Expected POI using 102.6 yards : 102.6 yards X 10 mils X 0.03599 (constant) = 36.9 inches

Expected POI using 102 yards : 102 yards X 10 mils X 0.03599 (constant) = 36.7 inches

Target 1 Actual POI : 37.1 inches

Target 2 Actual POI : 37.0 inches

Results for Target 1 : 102.6 yards (expected POI / actual POI) 36.9/37.1 = .9946 error of less than half of 1%
Results for Target 2 : 102.6 yards (expected POI / actual POI) 36.9/37.0 = .9973 error of a quarter of 1%

Results for Target 1 : 102 yards (expected POI / actual POI) 36.7/37.1 = .9892 error of slightly over 1%
Results for Target 2 : 102 yards (expected POI / actual POI) 36.7/37.0 = .9919 error of slightly under 1%

Conclusion : Tracking is Good To Go. Oh, I need a level on my rifle too as it looks like I cant.

**** Target was placed on backing using a carpenters level.

 

[EscapeVelocity]

So i just ordered the tracking test target on the hide here last week. I'll be testing my newly acquired Cronus BTR this weekend and verify my finding as well.

 

[Tyler Kemp]

Shoot me a message, I'll hook you up with a level

 

[Yoteski]

I actually did a tall target test myself this weekend on my Cronus BTR. Should have grabbed more pics. I actually found a bit of error between 8-10 mils; but only a .1 error. It also returned to zero perfectly. I did grab a pic or my 10 mil error. I have to say, the scope still really impresses me for the money.

 

[USMC 308]

Precise measurements are the key. If your distance to target is off, even slightly, it could explain that deviation in your picture. Measure from the scope turret to the target. This was my dilemma as I was getting some conflicting readings. No access to a long tape measurer so I'm trusting that the LRF reading was solid. As mentioned, the light and dark colored backings were causing a different reading consistently. Right before the target stand was a wood block with the lane number painted on it. That distance was 102.0....which leads me to think the 102.6 to target is the more reliable number.

 

[PDX1760]

Thanks for sharing your results!

 

[ThunderRun]

Have not done one of these in many years. My last time was with a top tier scope manufacturer back in 2003 or 04....and it did not go well. Rob 01 can attest.

After reading some feedback in another thread, I decided it was time to do one today. Now I assumed that in today's day and age, with the high degree of precision in the computer integrated machinery, a failed test should not be happening, nor should it be acceptable to the consumer.

Rifle : 6.5 CM Bergara Premier LRP rebarreled with a 27" Hawk Hill M40/24 contour 1/8
Scope : Athlon Cronus BTR 4.5-29x56 Mil/Mil
Ammunition : Hornady Match 140gr ELD Match (Factory)
Laser Rangefinder : Sig Kilo 2200 MR

Light wind, 90 degree day in Central Texas

Made Tall Target according to directions, placing a orange dot on zero and 10 mil (36 inch) marks.

I ran 2 separate tests using new marks on the target. Test Target 1 was 3 rounds at each setting (zero and 10 mils). Test Target 2 was 2 rounds at each setting (zero and 10 mils). I dialed up and down 10 mils after each shot.

Lazed target, took distance from turret to target. Here's where the fun begins. On a dark target, a reading of 102.6 yards was consistently recorded. On my white target, a reading of 102.0 was consistently recorded. I did not have access to a 300 ft tape measurer so I'll do 2 sets of calculations.

Expected POI using 102.6 yards : 102.6 yards X 10 mils X 0.03599 (constant) = 36.9 inches

Expected POI using 102 yards : 102 yards X 10 mils X 0.03599 (constant) = 36.7 inches

Target 1 Actual POI : 37.1 inches

Target 2 Actual POI : 37.0 inches

Results for Target 1 : 102.6 yards (expected POI / actual POI) 36.9/37.1 = .9946 error of less than half of 1%
Results for Target 2 : 102.6 yards (expected POI / actual POI) 36.9/37.0 = .9973 error of a quarter of 1%

Results for Target 1 : 102 yards (expected POI / actual POI) 36.7/37.1 = .9892 error of slightly over 1%
Results for Target 2 : 102 yards (expected POI / actual POI) 36.7/37.0 = .9919 error of slightly under 1%

Conclusion : Tracking is Good To Go. Oh, I need a level on my rifle too as it looks like I cant.

Nice job!

Quick question, how did you level your target? Carpenters level?

I got to spend some time behind a really cool "scope level." I was leary and had doubt, but quite frankly I was very impressed. Check out the Long Range Arms Send-It.
https://long-range-arms.myshopify.com/products/sendit

The level mounts close enough that you can see the light to correct for cant without ever taking your eyes off the reticle. It was daylight bright! I didn't think the electronic-level could compete with the accuracy of a bubble. I was wrong, it was even more sensitive.

 

[ThunderRun]

Precise measurements are the key. If your distance to target is off, even slightly, it could explain that deviation in your picture. Measure from the scope turret to the target. This was my dilemma as I was getting some conflicting readings. No access to a long tape measurer so I'm trusting that the LRF reading was solid. As mentioned, the light and dark colored backings were causing a different reading consistently. Right before the target stand was a wood block with the lane number painted on it. That distance was 102.0....which leads me to think the 102.6 to target is the more reliable number.

Good point, what is the stated accuracy of your LRF?

 

[USMC 308]

Good point, what is the stated accuracy of your LRF?

Found this :

Sig indicates that the Kilo is accurate to within .1 yard at distances under 100 yards. The accuracy diminishes as the range extends, which is normal.

 

[Dthomas3523]

Also, I’m sure most people know, but keep in mind the margin of error for the shooter and rifle. If your typical group is .5moa and you’re within .5 moa of the intended impact point the optic is probably tracking correctly.

Once you start getting into the 7-10 mil area, check your parallax. Vortex advised me that the further you crank the turrets, it can affect the plane of the lens in the erector.

 

[ThunderRun]

Also, I’m sure most people know, but keep in mind the margin of error for the shooter and rifle. If your typical group is .5moa and you’re within .5 moa of the intended impact point the optic is probably tracking correctly.

Once you start getting into the 7-10 mil area, check your parallax. Vortex advised me that the further you crank the turrets, it can affect the plane of the lens in the erector.

I agree. Nearly maxing out turrets does have some effect. You can do it, there's no risk to the scope, but id prefer to stay in that "sweet spot." It makes life a little easier! 34mm tubes and canted rails for me!

 

[scudzuki]

The target needs to be plumb, not level.
I have a big steel nut tied to some yellow fishing line I use to hang tall test targets.

 

[Scopes]

Eliminate a variable, 300 foot tape measure doesn't lie!

 

[AMGtuned]

The target needs to be plumb, not level.
I have a big steel nut tied to some yellow fishing line I use to hang tall test targets.

Wait, do you use the same tool for that?

 

[ThunderRun]

The target needs to be plumb, not level.
I have a big steel nut tied to some yellow fishing line I use to hang tall test targets.

Yes, you're right it needs to be plumb for a Tall Target test. Semantics right? My apologies. A box test, I suppose you could do either, level or plumb it. I prefer a carpenters level since the wind won't shift it, I don't have to worry about the string touching the target frame, and I don't have to wait for the plumb bob to steady up. You can plumb or level with most any carpenters level. I don't think it would matter in such a short distance, but your nut on a string can cause the string to shift slightly at the "fulcrum point" where the nut and string are tied together.