Mauser 98 Magnum in 450 rigby has double squre bridge. May be R igby uses different action. I was told Rigny's use barrelrd Mauser 98 magnum actions.I currently have a red dot on my .450, and I still agree with you. The single square bridge is a killer. For 16k I would like to at least have the option of mounting a regular optic on the gun. They offer the .416 rigby with a double square bridge, but not for the .450 rigby.
Krish