I installed the Talley bases on my 300HH and the rear base protrudes off the action over the opening. I think I remember a thread on this awhile back but can't locate it.

It's not that it doesn't work but are there any other options, custom two piece mounts etc., that would look a little nicer or is this just the nature of the beast?

I don't really have to have Talley but want something nice.

Turn the rear base 180 degrees. That should do it.

I've got Talley's on my pre-64 300 H&H and there isn't any protrusion. Talley makes two different models for the M70 pre-64's, make sure you get the correct one (based on screw hole spacing).