Zeroing Scope's Adjustments

[Bart B.]

Why does setting the scope's elevation and windage adjustments midpoint in their mechanical limits make the line of sight point away from the scope's optical axis that's on the outer tube's center?

 

[oldmanFCSA]

The adjustment range within the scope may not be perfectly centered with relationship to the outside tube.

Some scope base/ring combinations allow for windage adjustment by using side screws on basses to center the internal adjustment capability without using the internal adjustment.

Those of us that shoot ELR (Extra Long Range) use scope bases with "cant" built in to permit centering of scope distance range without using most of the adjustment range. Such as a 15, 30, 55, etc. MOA base Cant. (Front of base is thinner to tip scope forward).

This supposedly allows for best strength of internals and the most capability of any future adjustment for range or windage.

YMMV.

 

[Bart B.]

The adjustment range within the scope may not be perfectly centered with relationship to the outside tube.

I've never seen a scope that was. They all quit moving the LOS left and down before reaching the LOF right and up mechanical limits.