Old world technology......100 year old rangefinder?

[Pistolier60]

Anybody ever seen one of these? It was in some old reloading stuff I bought at a Pawn shop back in the 1980's. I finally found some instructions for how it works online, although they're pretty confusing.

 

[Redleg]

Forward Observers use those formulas for ranging and to adjust artillery fires.

 

[Pistolier60]

Apparently this one is missing a ring and cord for it to be complete. The directions make more sense when you know that. Should be like this photo I found on google .

 

[Hayata]

There's just no tellin' what you'll find on ODT from one day to the next.

Thanks for posting!