Scope Damage. How to check.

[Dmorcos]

Is there a method or a way to check a scope for damage caused by magnum springers other than the obvious broken, rattling piece inside a scope?

And how do the manufacturers check scopes that are sent in for such suspected damage?

 

[Guest]

"Dmorcos"Is there a method or a way to check a scope for damage caused by magnum springers other than the obvious broken, rattling piece inside a scope?

And how do the manufacturers check scopes that are sent in for such suspected damage?

One symptom of a scope that is broken is that it will not hold zero. You might set your zero and shoot three or four shots and suddenly the zero has moved and two or three go into a different spot. The problem there is having a pellet that you know for certain is shooting well in your rifle because these small variations can be covered up by poorly grouping pellets. Probably the best way is to swap out the questionable scope with a known good scope and see if the rifle will then group. If it does it is the scope. If it doesn't group after you swap out the scope with a known good scope, then you have to have a look at the rings and base(s).

If you are like me you will then come to the realization that you never did check your screws. You will then check them and find one of the bedding screws is loose...

As far as I know I am the only person who does that.

 

[Ziabeam]

I keep two pieces of scope rail in a drawer to check various scope functions, one picatinny rail and one 3/8" or 11mm.

Mounting the applicable rail in a sturdy swivel-base vise makes it possible to quickly mount and aim a scope (already outfitted with rings) at a fixed object to check the following;

• Box test... moving right, down, left and up to the starting point, then reversing the same amounts to ensure the reticle follows in its own footsteps without backlash
• Checking to see if the center of the reticle remains on target when zooming in or out. FFP scopes can use any portion of the reticle for this test. I've had brand new scopes fail this test miserably, observing shifts of over 3 inches at 25 yards, (usually vertical shifts). The shift usually manifests itself instantly during the point of changing direction with the zoom barrel. Example; abruptly "UP" when zooming in after having zoomed out, and visa versa abrupt "DOWN" shift when zooming out after having zoomed in.
• Checking parallax backlash to determine if the parallax is correct at known distances whether reducing distance setting or increasing it.

If your vise is particularly stable it may be possible to impart a modest hammer blow to the front or rear of its base with a small hammer, crudely simulating the effects of recoil, in order to see what if any changes occur. Noting if the blow "settles" any scope inputs that preceded the hammer blow.

Hypothetical example,

1. Zoom out then zoom in, observed downward elevation shift
2. Administer hammer strike... see if reticle shifts back up
3. Reverse the order (zoom out then in) repeat scrutiny, et-al
4. Apply same procedure for left to right/right to left... up/down backlash to see if vibration causes the adjustments to "settle"
   [/LIST=1]
   Many premium scopes have proved their worthlessness, and cheap scopes "earned their keep" after being submitted to the above improvised battery of tests on my unbiased vise. It (vise) knows no favorites.
   

 

[Dmorcos]

Thanks for all the help.
Ziabeam, I certainly like your method. As soon as I get back from a fortnight trip, I will test using your listed method.

 

[sharroff]

Another option (less violent) is to try the box test. Shoot at a target center and get your point of impact. Turn the scope one full revolution to the right, one full revolution down, one full revolution to the left, and one full revolution up. Shoot again. Pellet should still be on the initial POI.