I've been doing some research on the use of this Model 1917 Panoramic Sight made by THe Warner & Swasey Co.
Unconfirmed, I found that they might have been used on AEF 14" railway guns.
Another unconfirmed, they might have been used on 10" field artillery guns.
Confirmed, I found that they were used, post war, on several of the 14" guns mounted for US costal defense around 1920.
Anyone have more info, please feel free to pass along.
Here are some photos:
Russ & Son