Anyone recognize the base in these pictures? (I ran across someone asking for info on another forum)

I've not seen one exactly like this but similar ones made for other single shot rifles. If it's a custom, it should be pretty easy to make one.

Home made, I suspect.

look at this companys ramp over

http://www.eabco.net/Ruger-Num...r-Style_p_14160.html

Looks like a factory quarter-rib that's been cut and milled to mount on top of the action instead of in front of it/on the barrel.

Raamws post seemed to nail it..

Its a mess in my opine, It is very easy to just install a set of Talleys on the existing quarter rib and sure looks a lot better IMO...those gaps in the base are great for collecting mud dobbers and such.