Rifle Scopes Parallax adjustments in Fixed Scope

[sirhrmechanic]

A thread down in the PX (and a subsequent Google search) raised a question:

Can you adjust parallax in fixed power scopes (that don't have an adjustment ring) by moving the objective lens inside the bell (or tube?)

The thread in the PX and this description seem to indicate that it is possible: http://fuzzylimey.net/projects/parallax.html

However, I would think that moving the objective and its carrier rings would compromise the seals in the scope? I would not think those are supposed to be moved outside the factory and that moving those threads would cause leaks? Maybe not a problem in low end scopes as described in the article above. But what about in high-end optics or gas/nitrogen filled scopes?

This is a purely academic question and I don't intend to do it. But would be interested to hear from those in the know whether it is a recommended practice or not?

Cheers, Sirhr

 

[doc76251]

Re: Parallax adjustments in Fixed Scope

It will depend GREATLY on how your optic is designed. Some have dual lock rings (one on each side of the glass). Some are there own housing, which is preferred if your going to try this at home, as the lens is locked inside a tube which is movable inside the bell. You best know what you have before breaking the "spanner" out to adjust your lock ring.

Cheers,

Doc

 

[Lowlight]

Re: Parallax adjustments in Fixed Scope

I would leave it most scopes are pre-set to be parallax free at a given range and in 99% of the cases will continue to be so well beyond.

The key to staying parallax free is to maintain a consistent and proper cheek weld, also it would depend on what power the scope is. Lower power scopes, 10X and lower are far more forgiving then the higher magnification ones that actually adjust the parallax.

Coming from a Unertl background I can tell you adjusting the parallax via a spanner is a lot harder than it sounds. You have to have a calibrated eye ball to pull it off correctly.

If the scope shipped without it, I wouldn't be messing with it