How to check scope tracking

[tenring]

I have serious questions about my scope's tracking, especially at 200 yds and beyond. I am familiar with one shot per corner of a 1" square. But is this the best method?

 

[Preacher]

I usually do the,box) test on a 6 inch format at 100 and 300 yards to see if all is well.
I don't know of any other way to check a scopes tracking out..........

 

[Forum Boss]

A few other bits of advice:

1. Check ALL the mounting parts and screws. We've seen more than a few rifles with $150.00 rings attached to rails that weren't attached properly or had loose screws.

2. Run the scope through the FULL range of its elevation and windage travel a couple times before you do the box test. This help ensure there is no binding inside the turret and that the springs are functioning correctly.

There are a couple good tracking targets on our targets page: http://www.6mmbr.com/targets.html

The U.S. Palma Team also has some nice targets with grid patterns.

 

[BoydAllen]

One way to help a scope track better is to always finish your adjustment turning the knob clockwise,,assuming RH adjustment threads). This is not my idea. I got it from the late Dick Thomas of Premier Reticles. For example, if you are making an adjustment that requires you to turn the knob in a counterclockwise direction, go past your intended adjustment by several clicks, and come back to it turning in a clockwise direction. If you do not follow this procedure, you are depending on the spring that tensions the erector tube against the adjustment screws to work perfectly. Friction may keep this from happening. There is also the issue of which side of the thread is loaded after the adjustment is finished.

Another suggestion-
Once when a very good shooter was having a scope problem, I suggested that he run the adjustments to their limits,both ways) and then back to where they were. This solved his problem.,The scope was not holding its adjustment, resulting in enlarged groups.) He went on to win a yardage with the same scope.

 

[tenring]

Thanks guys; I did run this NF 12-42BR adjustments both elevation and windage to opposite ends. I have a perfect 2" square made up, and will try the box at 200 yards,kinda hard to do with 1/8 clicks at 300). I returned it to NF couple months ago with same complaint. Might have to go back again.

 

[Fred Bohl]

If your concern is tracking/reproducibility of the scopes internal adjustment, a box test using a down range target is only valid if the scope is rigidly secured to the rifle that is rigidly secured in a gun vise that in turn is rigidly secured to a ridged bench that rigidly secured to the ground. In other words, only the internal parts of the scope must be moving relative to the target during the test.

NOTE: to move the POA 0.125 MOA, the needed displacement of the rifle over the rear to front bag distance is about 0.001 inch for typical bag spacing or the needed displacement of the erector tube position is about 0.0001 inch for typical erector tube length.

When you return a scope to the manufacturers repair center for a tracking error complaint, they put the scope on an optical test bench with the scope clamped in v-blocks aligned precisely with an auto collimator,which will show the angular alignment of the scope optical axis usually in arc seconds). The closest we can usually come to this test is to use a commercial “boresighter” on a spud in the barrel. While these are limited in resolution,the grid squares are typically 4 MOA apart), a least they will be rigidly coupled to the rifle and scope during the box test. Also, with a little practice, you can do a far better and more repeatable tracking test than with a rifle on bags viewing a target at the range - IMHO.