Re-Parallaxing

[Muskett]

Some are permanently bonded, and if so don't try. Scopes like Zeiss.
Some are just stiff or just have a lock glue that will need cracking. Even a bit of gentle heat can get them going. Nothing about it is risk free though.

A scope lens rubber can work, but where I got mine I can't remember.

I use some cut down steel rulers which are strong enough and fit the notches. Pliers and other tools are scary to use as it only takes one jolt to scratch a lens.
Some scopes are very stiff, some a bit too loose.

Frankly, there is all a bit of luck in it. Set it so that at top mag is your "ideal" range. Those scopes I've done, like the odd Tasco or Optima, I've set at 25m.

When you move the lens the zero goes off. Once set leave alone and if anything Locktite Blue so it won't budge unless wanted to.

[BC312]

I done this in the past especially focusing at max at 25 yards where the picture was a blurr. A quick follow up and now a clear sight picture.

[Bellycrawler]

All I did on some old Hawke Sport HD xcopes, undo the front lock ring, unscrew the lens, tighten up the lock ring. Seemed simple enough. Nor tried it on other scopes thought.

[ToniD]

Thank you all for that.