Cutting holes in steel bases (scope mounts)

[Ray B]

I have an pre-64 M70 that has rear mount hole spacing .435:. The scope I want to put on the rifle has a 30mm tube. the scope presently has Leupold STD dovetail/pivot rings which I would like to retain. The problem is that all the Leupold/Redfield bases that I find are either .86 or .33". The bases are quite hard and I understand are made by the sintered process which is quite resistant to drilling. Is there some way to cut a hole in the existing base that will maintain the integrity of the base and not cost more than getting a new set of bases and rings?

 

[Shootist43]

Warne has bases for those old Winchesters, just be careful when you order to get the right ones.

 

[Shawn.54]

If you could find a machine shop with CNC a carbide end mill would be up to the task.
Shawn

 

[Ray B]

After further investigation the attempts to get either bases that would fit the rifle and match to Leupold dovetail pivot rings, or 30mm rings to fit the Weaver style bases I gave up and ordered a set of Talley bases and QD rings. So the rifle should be set- I just have a set of mis-matched rings and bases- oh well, such a problem to have.