If it means anything, Jack Lott mounted a 2.5X Weaver on his custom Mauser.
Or, if you can find one (they're scarce as hens teeth) you might consider a 2.5X Valor. I have one on my .45-70 Mauser, and, with my handloads, it takes quite a bit of punishment. I discussed this scope with a very knowledgeable fella, and he told me that the Valors had a reputation as a good, rugged scope that would stand up to hard kicking big bores.
I'm not real big on mounting variable powered scopes on the big bores. I can't help feeling that the extra mechanisms in the variables are more prone to failure than a simple fixed power scope. I guess I'm just old fashioned that way.