I posted some pictures in another thread of a couple different Redfield's I have, not knowing what number they were , one must have been an 80 and the other a 70. I think they offered different types of knobs as an option on these, hunting or target, so the knobs may vary on the same model.

The one on the right is a Lyman 56.
[Linked Image]

There is a difference in the clearance of the two Redfield's with the one that is probably a 70 (middle) not clearing the wood on the gun I tried it on, details & pictures here - re-i-s-o-lyman-56-s#Post16712308

Gene