I have 2 of those scopes with 40mm objectives, and I think another 2 with 50mm objectives - they are EXCELLENT scopes. As for the Ruger #1, given the contour - or lack thereof - of the barrel, you really shouldn't use a scope with objectives larger than 40mm, especially when the scope, like the one you want, has an AO on it. Even then you will use higher than normal rings.
Zachary