Restore Scope Settings to Factory Zero


PDA






jbeltz7
September 3, 2008, 09:36 PM
Any rule-of-thumb instructions on how to restore a used scope to factory zero?

Is a good starting point midway between full CW and CCW on both elevation and windage?

TIA

If you enjoyed reading about "Restore Scope Settings to Factory Zero" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
Coltdriver
September 3, 2008, 09:43 PM
All the way to the left, all the way to the right, half way back will at least get you to a known point.

Unless you have adjustable windage on your rings (which can be a royal pain).

On my single shot and bolt rifles I bore sight to the target and can usually get in the 10 inch ring pretty reliably at 100 yards so I can adjust from there.

Omnivore
September 3, 2008, 09:52 PM
That's a good enough starting point for anyone.

I once read an article on scopes that stressed the importance of re-centering a scope every time you remove it, or anytime you get a new scope. The reason being that all those adjustments made in the past are compounding, and you just lose track of where your adjustments are, or some such nonsense.

Unless you have a mount that's adjustable for W&E however, it makes no sense at all. No matter where the adjustments start, they're going to end up in exactly the place required for a zero on the next installation. No matter what.

That being said, if for some reason you really do need to optically center your reticle with the tube, remove it from the rings. Cut a stout cardboard box, or wooden box, with two "V" cuts-- one for each end of the scope tube (one forward of the turret and one behind the turret). You can line the "V" cuts with felt for easy rotation of the scope and to protect its finish. Rest the scope in your "V" notch stand and look through it while you rotate the scope with one hand. If the reticle's aiming point orbits around the optical center, it's not centered. If it stays put and doesn't wobble, it's optically centered. I don't know what that does for you, but it's centered. Once you mount the scope, you're going to move the reticle to zero the rifle, so what have you accomplished?

I might one day be convinced that there is a reason for doing this, but right now I can't think of one unless you have an adjustable mount.

jbeltz7
September 3, 2008, 10:18 PM
Thanks, my intent was to get it on the paper from the start. FYI - The used 3x9 Tasco World Class Scope I just mounted takes ~7.5 full turns on both elev and wind to go from full CW to full CCW. I just set both to midway.
Before the flames I have both Burris and Leupold on four other rifles and for the money the Tasco seems like a very good compromise. Not quite as bright or clear by to my inexperienced eyes not $400 worth of difference. Whether or not it will hold zero is yet to be seen.

jbeltz7
September 3, 2008, 10:23 PM
Good info, tks

That being said, if for some reason you really do need to optically center your reticle with the tube, remove it from the rings. Cut a stout cardboard box, or wooden box, with two "V" cuts-- one for each end of the scope tube (one forward of the turret and one behind the turret). You can line the "V" cuts with felt for easy rotation of the scope and to protect its finish. Rest the scope in your "V" notch stand and look through it while you rotate the scope with one hand. If the reticle's aiming point orbits around the optical center, it's not centered. If it stays put and doesn't wobble, it's optically centered. I don't know what that does for you, but it's centered. Once you mount the scope, you're going to move the reticle to zero the rifle, so what have you accomplished?

Omnivore
September 3, 2008, 10:48 PM
A good way to start is what you've already done, but it's arbitrary-- don't expect to be close to a decent zero. Bore sighting is another way, which is a little more accurate for an initial setting-- if you can look through the bore, adjust the scope until the scope's aiming point is on the same place on the target as the bore at about 20 to 25 yards. Some rifles of course will not allow this as you can't see through the bore.

Fire on paper at 25 yards from a supported position. Closer if for some reason it's so far off that you're missing the paper, but get to 25 as soon as you're hitting the paper. Fire five shots carefully, keeping the crosshairs on exactly the same point on the target for each shot. Determine the center of your group and make adjustments accordingly. At 25 yards, your adjustment clicks will have one fourth the indicated MOA value in inches (if one click = 1/4 MOA, then at 25 yards one click will equal about 1/16", to move your group center one inch up, count sixteen clicks "up", etc.). Once you're dead-on at 25, go out to 100 yards and make your final adjustments (or to 200, and then 300, depending on your desired zero).

Once you're done, your scope's elevation adjustment will most likely be quite a ways off from optical center. That's just reality, unless you happen to have the world's most superbly built and installed mount that also has several minutes of angle elevation built into it.

alsipd
September 27, 2010, 11:43 AM
The absolute way to center a scope is to use a mirror.

Step one, place mirror in front of the objective lens and use a rubber band to hold it there

Step two, look through the scope to see two sets of reticles

Step three, move the windage and elevation screws until the two reticles are together and look as if they are one

Step four, remove the mirror and use a bore sighter to sight the rifle

You have now set the reticle back to the factory center.

If you enjoyed reading about "Restore Scope Settings to Factory Zero" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!