finding center of adjustement on a scope.

[Kart29]

So, someone  gave me an old Redfield 4X scope that I want to mount on my Hand-rifle.  I've been having problems getting it to shoot decent groups and so wanted to try a different and maybe better scope.  So, I've got this used Redfield.

Here's my question: Since this is a used scope, I have no idea how far the adjustment screws have been turned to get it sighted in on its previous rifle.  I'd like to get the internals of the scope set in the middle before I mount it and sight it in on my rifle.  But, I don't know how to get the scope adjusted to its natural "center" so there is an even amount of adjment available in all directions.  Can I just turn the adjustement screws to find the limits in all directions, and then split the difference?  I've never turned and adjustment screw all the way and I don't know what happens.  Does it just stop turning or does it come completely unscrewed?

Thanks for helping a dummy.

[Whelen Man]

Exactly like you said is what I've always done.  Simply move the adjustment to its limit in one direction ( it will stop) and then count clicks as you adjust in the opposite direction until you hit the limit again.  Divide in half and move that many clicks back and you should be right.  It will improve scope performance having the crosshair limits centered before mounting.  If necessary do a little shimming to get to dead center or offset your mounting to allow for more range adjustment.

[ogo]

Yep and yeper***************ogo

[quickdtoo]

Counting clicks is a PITA and on some scopes, it will jam the adjustment. A real simple way to center the reticle is to place the objective end of the scope against a mirror, look thru the scope and you should see to 2 sets of X-hairs, the actual reticle and the reflection, adjust the turret adjustments until they line up and you only see one set. You may have to experiement with light angles, but it works on 99% of the scopes I've tried it on, the better part of 50 different scopes. This is the method recommended by Leupold which can be found in their answer guide under resouces.

Tim

[Mitch in MI]

A real simple way to center the reticle is to place the objective end of the scope against a mirror, look thru the scope and you should see to 2 sets of X-hairs...

That's a new one on me. Seems simpler than putting the scope in v-blocks and aiming it at a far target while turning it in the v-blocks.

[Kart29]

I did like quickdtoo said and it worked.  It was really interesting to watch one set of crosshairs in the mirror remain stationary while the other set moved around to the movement of the adjustment dials.

Neat trick!  Thanks quick.

[quickdtoo]

You're very welcome, always glad to share.... :wink:

Tim

[FirstFreedom]

Can I just turn the adjustement screws to find the limits in all directions, and then split the difference?

Yes.

I've never turned and adjustment screw all the way and I don't know what happens. Does it [...] come completely unscrewed?

Nope, not unless it's some horridly cheap scope, and even then probably not.

Yeah, what I do is go until you reach one end or the other, one click at a time, until you feel undue pressure.  When you do feel that pressure, don't force it obviously.  (However, sometimes they are stiff and you think you're at the end when you're not, so you have to apply just the right amount of pressure to figure out if you're at the end).  Then start counting and go all the way back to the other end, for the total clicks.  Then write this number down in a spreadsheet on your puter.  Divide by 2, and count back to the middle.  Repeat with elevation (if you did windage first), then bore sight it with both axes in the middle like that, for maximum flexibility in fine tuning.

Having said all that, quickdtoo's method sounds even better!