Technical question for all of you who know what you are doing

[Bart B]

One other thing I've found interesting about rifle scopes is how much movement's available in all four directions when the elevation and windage knobs are set such that the reticule's dead centered on the scope's mechanical axis. After doing this, then bore sighting to see how far off the mounting rings and bases are aligned with the bore axis. Some rifles with some sets of bases and rings are pretty bad.

First, make two V blocks then attach (nail, screw) them to a board several inches apart such that the scope can rest in them and spin free. Then clamp that board in something that you can see stuff through the V's at least 25 yards away.

Second, take the scope out of its rings, lay it in the V blocks, look through it then rotate it. The image will spin in a circle of some amount.

Third, move the adjustments as the scope's spun in the V blocks until the image rotates about a single point. When this happens, the scope's internal tube that's moved by the adjustments is now centered and well aligned with the main tube axis.

Put the scope back in its rings on the bases then check its alignment by bore sighting. See where the bore points relative to where the scope's reticule is. Prepare to be surprised.

[Scot E]

Originally Posted by Bart B

One other thing I've found interesting about rifle scopes is how much movement's available in all four directions when the elevation and windage knobs are set such that the reticule's dead centered on the scope's mechanical axis. After doing this, then bore sighting to see how far off the mounting rings and bases are aligned with the bore axis. Some rifles with some sets of bases and rings are pretty bad.

First, make two V blocks then attach (nail, screw) them to a board several inches apart such that the scope can rest in them and spin free. Then clamp that board in something that you can see stuff through the V's at least 25 yards away.

Second, take the scope out of its rings, lay it in the V blocks, look through it then rotate it. The image will spin in a circle of some amount.

Third, move the adjustments as the scope's spun in the V blocks until the image rotates about a single point. When this happens, the scope's internal tube that's moved by the adjustments is now centered and well aligned with the main tube axis.

Put the scope back in its rings on the bases then check its alignment by bore sighting. See where the bore points relative to where the scope's reticule is. Prepare to be surprised.

Very true. This is one of the reasons I like the Burris Signature Rings so well. You can eliminate all of that error with the rings and have all of the internals for dialing and shooting.

Scot E.