Walther LGR - diopter sight question

[Walnut92]

Can anyone tell me how to open the rear sight to clean the rear of the lens?

I can clean the front of the lens but not sure how to get to the rear - i.e. which is through the pinhole. There's dust on it!

I'm hoping it unscrews, but don't want to damage something by trying the wrong process.

Thanks.

[Tim S]

That depends on the eyepiece. I presume it's a variable iris type with filters (a "diopter" type adjustable focu lens is not allowed in most 10m airgun matches). I would start by unscrewing the eyepiece from the sight. Gehmann iris eyepieces have a locking nut at the front (rearsight side) that needs a small spanner. Gehmann eyepieces unscrew at the back exposing the filter wheel. I can't remember how Centras disassemble.

[Walnut92]

Thanks Tim, It is an original Walther sight.

The eyepiece has a knurled larger ring and where it swages down to meet the moving part of the sight, it appears to go up against a small ring with two flats on it.

It does suggest that the bell-shaped pinhole eyepiece unscrews. Perhaps it's just stuck..?

[Tim S]

To be sure, are there numbers engraved around the body of the eyepiece? One with colour filters will often have the colours marked on the outside, although these may be faded.

A Gehmann will be marked W Gehmann Karlsruhe (or similar) on the rear face, around the peep.

[Walnut92]

Tim - it't not a Gehman. Here it is.

it's the knurled eye ring I need to undo to access the glass.

[Albert T]

This is a standard old type walther diopter. The knurled ring with the two flat spots is screwed in the diopter and can be screwed out the usual way. The flat parts are made so that a special key can be used to unscrew it. The diopter has no glass. The knurled ring has an opening of 1.1mm and is sctewd into the block that moves sideways or up-down when the sightscrews are turned.
For air rifle 10m you need 5 clicks to move the POI 1 ring distance; for 50m smallbore you need 3-4 click s to move the POI 1 ring distance.

Albert T
(The Netherlands)

[Tim S]

Tim - it't not a Gehman. Here it is.

it's the knurled eye ring I need to undo to access the glass.

I see. I was thinking it was a Gehmann because you mentioned glass. That's a standard aperture, a metal disc with a hole. There is no glass.

To remove it, grasp the back firmly and unscrew anti-clockwise. Alternatively buy a can of compressed air from an electronics shop and give it a blast.

[Walnut92]

Brilliant, thank you both.

No glass - correct! Sorry, I perhaps should have looked more carefully!

Cleaned with cotton bud and all is good! Was very dusty and hence it was distracting the view even with only a pinhole.