I think my scope might not be tracking correctly.

[tinker]

New to using a ballistic calculator. I have Geoballistics.

I built a new rifle and took it out for some silhouette shooting and did really bad.

So I went to my local range and confirmed zero @ 100 yards and made a jagged hoe 5 shots group and the Labradar said 2750-2768 fps.

I originally had 2775 in the app so I switched it to 2750 as a most of the 5 were right at that number. Then punched in 200 yards and it called for .4 mils
I know my height over bore is correct, I selected the bullet from the app's library (140 gr SMK, shooting 6.5cm).

Then took a shot at 200 ....it impacted a few inches low and I had to come up to .6 mils. Now I double checked all my data and ended up trueing the muzzle velocity and it corrected it to 2499fps. That seems like a LOT.

I am inclined to think possibly the scope is not tracking correctly.
In two weeks I am heading to a friends range where I can try some various distances so test some things and I will bring a couple other scopes as well.

I'm just curious if that seems like a normal number to be off for trueing? Or is that unlikely?

 

[TACC]

Scope make and model?

 

[Downtown]

Not too hard to check tracking. Frank and Mark now do it before every class. Search around on this site for more info.

Thread 'Confirming rifle scope tracking…..can it be done without ammunition?' https://www.snipershide.com/shootin...g…-can-it-be-done-without-ammunition.7020820/

 

[diggler1833]

Did you shoot it at 100 again to confirm zero or see if something came loose?

Wait until you get a bit further out before you start trying to true the velocity. 500 - 600 is where most people do that. The reason being that 30 FPS starts to show up at 600...it doesn't at 200. Conversely, truing at 200 in your case will have you way over correcting.

Also, did you come off the rifle/change positions/shooting platforms to shoot off of when you went to 100 from 200? Changing how your body interacts with the recoil will affect POI, and it isn't uncommon to drop a tenth mil or two when going from seated cock-eyed at a concrete bench to prone behind the rifle on dirt. I just ask because we want to address every possible variable.

Certainly, making/buying a tall target with reference points and conducting a tracking test is going to be the best way to figure out if you have a tracking error. It can certainly happen, but you usually won't see it on even halfway decent optics at just the .4 - .6 mil mark...usually you'll see a .1 error at 5 to 10 full mils.

 

[Baron23]

making/buying a tall target with reference points and conducting a tracking test is going to be the best way

And this is an excellent target and works for this purpose extremely well, IMO. Key is to have some sort of fixture to hold the scope steady while dialing up/down and left/right.

Store - Box to Bench Precision

Snipers Hide 100 Yard Scope Tracking Target - MIL - MOA - For Milliradian and Minute of Angle Scopes - True Minute of Angle - Precision Shooting -

www.boxtobenchprecision.com

And yes, as you said, you can just make one.

 

[moaorbust]

As long as the appropriate scope and mount screws are torqued the issue could be the mechanism got bound a little. Binding happens more often in cold weather. Just turn the caps a full rotation either way to clear a bind.

 

[Lowlight]

Why Gravity Ballistics is so much better,

There are no inputs, there is no chance of making a mistake by using an incorrect value.

Gravity Ballistics dopes a rifle than any other App out there.



Use this and Dope your rifle, if this does not work, something is wrong

Fill out, will look like this:

 

[tinker]

Scope make and model?

The cheaper gen 2 razor but it shouldn't matter.

 

[tinker]

Did you shoot it at 100 again to confirm zero or see if something came loose?

Wait until you get a bit further out before you start trying to true the velocity. 500 - 600 is where most people do that. The reason being that 30 FPS starts to show up at 600...it doesn't at 200. Conversely, truing at 200 in your case will have you way over correcting.

Also, did you come off the rifle/change positions/shooting platforms to shoot off of when you went to 100 from 200? Changing how your body interacts with the recoil will affect POI, and it isn't uncommon to drop a tenth mil or two when going from seated cock-eyed at a concrete bench to prone behind the rifle on dirt. I just ask because we want to address every possible variable.

Certainly, making/buying a tall target with reference points and conducting a tracking test is going to be the best way to figure out if you have a tracking error. It can certainly happen, but you usually won't see it on even halfway decent optics at just the .4 - .6 mil mark...usually you'll see a .1 error at 5 to 10 full mils.

All same position. Same everything.

But the rest was what I was thinking. I guess I won't really know until I get to the range to try some stuff. Definitely going to bring a few other optics that will mount in their own mounts each ahead of time.