FWIW the opinion of someone who worked with optical systems for 50 years.
As long as it "
seems in focus" & the reticule does not exhibit parallax, then you're good to go. It is actually mind-numbingly simple to fix the scale if it really bothers you though. A monkey with a watchmaker's screwdriver could do it.
Notice I say "
seems" what can happen is the eye can be distracted by trying to focus the out of position "Aeriel Image" produced by a poorly set AO front end, & try to work out 2 different planes of focus at the same time.
While the front end (objective) optics are similar to a camera they aren't identical so its not a great comparison. Camera lenses create a "real" image onto a fixed plane, a telescope (or sight, or monocular) collects this image & passes it on to a second set of optics (the eyepiece group) which project out as a "Virtual image" appearing at infinity so the human eye can focus inside the tube.
The focusing scale is engraved on an outer tube (or ring) which is clamped to the actual objective body holding the lenses. This is done at the factory to simplify construction & assembly & the "clamp" can slip. If you want to fix it yourself try this.
BUY A SET OF WATCHMAKER'S SCREWDRIVERS (always use the right tool for the job!)
Set up the rifle & scope in a fixed location with a clear view of a target at a known distance.
Set the objective for zero parallax by looking through it. This sets up the actual focus tube & optics correctly, only the external scale is now "off".
Back off the 3 (maybe 4) small recessed grub screws till the outer ring ONLY moves.
Turn the scale to the measured (or known) target distance. Don't let the internal tube move, if it does re-tighten & reset the optic.
Tighten the screws evenly till it locks again.
That's it you're done.
