The gun came today. It's as nice as the photos depict. The dovetail on the barrel is about 10 inches long. That's what the rear open sight is mounted on. I'm going to try to find an aperture sight or scope base to fit that dovetail. I actually have a target aperture sight with a dovetail mount, but it is too small for the rifle. I'll do some research after I measure it carefully.

Thanks for all the help.