I have a Ruger No.1 in 50-110 but it has been rebarreled.
Here: http://forums.nitroexpress.com/showflat.php?Cat=0&Number=167790&an=0&page=7#Post167790
The extractor and feed channel can take it but can't say if your barrel has enough meat in it to rebore.

That said, I would go with the 50-110 so you could potentially have a broader range of loading to work with.
Look up Mike Tulowitzky, he works on a lot of No.1s and should be able to tell you what can be done with your barrel.