TR shooters what is this?

[jimmyjazz]

Bought some used sights from a friend and it came with one of these ... I can't figure out where it goes.

It wont screw onto the back of the rear sight??

Cheers

 

[prinum]

Looks like a part of rear diopter

 

[JayCarver]

Adjustable Iris???

 

[Brutus]

Maybe a receptacle for a corrective lens?

 

[maynard]

Looks like a part of rear diopter

Is there a lens in it?

 

[jimmyjazz]

Yes it appears 1.5X but I can't see how to attach it to the Gehmann Iris that this came with, they both have male threads.
The guy that sold it to me had no idea how they attached.

 

[guntech]

I can say for sure, it does screw into and fits some particular sight...

I sold something like that in 1968 or 69.

 

[Ian Robertson]

There mat be a screw in cover on the iris that if you remove it you can screw this in instead. It also looks like you have more than one jam nut on the male thread that would screw into the sight

 

[maynard]

There mat be a screw in cover on the iris that if you remove it you can screw this in instead. It also looks like you have more than one jam nut on the male thread that would screw into the sight

Take off the jam nut on the left hand side, that screws into the sight. The iris for that diopter screws into the right side. If you don't have that part (iris) you are screwed, a regular iris will not screw into it. Looks like a Gehmann iris.