Optically centering ?

[jdk1]

In bright daylight, sit a mirror on the table and sit the scope upright with the objective bell upwards, look down through it and you will see two sets of crosshairs. Adjust the windage and elevation until they are superimposed on one another. Scope is now optically centred.

I would be poking the buyer about his firearms history, and doing a bit of digging. Nobody likes a walt.

Any sales I see him involved in across the forums and I will be sending a warning pm to the other parties.

[billywhizz1]

well done I think that's the way too deal with this wally.

[Phil Russell]

If this is not the place to ask, forgive me ... optically centering. I believe this is where the reticle image is positioned at the central axis of the scope body and hence hopefully at the centre of the lens system? I can accept that this could be at the point where the adjusters, up/down, side to side are in the mid positions; but that this may not be so.... but should not be far off.
Now, you optically centre the scope then mount it and proceed to zero it. You do this by twiddling the adjusters up/down, side to side. So you are moving the aim point away from the optical centre. So why could this not be done without the process of optically centreing? Or should you optically centre a scope and then adjust poi by using adjustable mounts.
Or am I missing the point?? Much as I miss the target?? I have never optically centred a scope ... am I missing out on something?
I guess I am just being daft but would welcome enlightenment (no pun intended).
Cheers, Phil

[Bellycrawler]

If this is not the place to ask, forgive me ... optically centering. I believe this is where the reticle image is positioned at the central axis of the scope body and hence hopefully at the centre of the lens system? I can accept that this could be at the point where the adjusters, up/down, side to side are in the mid positions; but that this may not be so.... but should not be far off.
Now, you optically centre the scope then mount it and proceed to zero it. You do this by twiddling the adjusters up/down, side to side. So you are moving the aim point away from the optical centre. So why could this not be done without the process of optically centreing? Or should you optically centre a scope and then adjust poi by using adjustable mounts.
Or am I missing the point?? Much as I miss the target?? I have never optically centred a scope ... am I missing out on something?
I guess I am just being daft but would welcome enlightenment (no pun intended).
Cheers, Phil

I've been reading this post with interest, you learn something new everyday & I hadn't heard of it before. Sounds handy for a quick check that everything is moving ok & working order before you go through the hassle of mounting a scope or when you get a problem to either confirm or remove the is my scope faulty question.

[thisisdonald]

I like to do it with a known good scope when I get a new gun. You shoot at a big piece of paper and see where the shot lands.
Assuming your scope is dead on centre with the cylinder/mounts you get an idea of how well centred the barrel is with the cylinder.
If you are lucky your shot will land somewhere in the vertical plane, meaning your mounts and dovetails are in line with the barrel. If you are unlucky and your shot lands left or right if centre, you can try and track down the problem... it could be your mounts, could be the barrel is bent sideways, could be a few things..
To me, centering the scope is just removing a variable, thereby exposing others

[thisisdonald]

Also, if your shot lands pretty close to centre of crosshairs, requiring only a few clicks here and there to get zeroed, some will say that you will get maximum light transmission through the centre of the scope.
It also helps for folk that like to dial in ranges, rather than use aim points

[krisko]

Imagine some people don’t use mildots but they dial in instead, Their aimpont is always the middle of the crosshairs. And they keep messing around with their elevation turrets depending on the range to target


they have to use shims or 10,20,25moa rails to help the scope to look Down without having to over adjust over travel on the elevation. Without shimming or added MOA to rail The outer tube of the scope is aligned/parallel with the action but then you have to point the inner tube the erector tube to follow the pellet trajectory! So the inner tube invisible from outside is pointing down!

Those who dial prefer many turns clockwise and anti-clockwise without worrying about running out of adjustment one way or the other.

With airguns for example at close ranges when the scope is high over the barrel you can’t even dial in ever, it is just too much, the pellet goes way under the optical axis as the bore is always lower than the scope vertically. of course low magnification helps.

Also the how much per click step is also a factor plus different scope allow different adjustment ranges.

Of course if the bore is not coaxial or the barrel is bent, that’s not going to help lol.