How does one convert an A3 to A4 ????

[Chuckindenver]

the holes were drilled before heat treatment, tapped afterward,
the shims were mostly used for the 330 scope, as it didnt have enough adjustment, iv yet to have to use shims with a Lyman or modern scope..
i can tell you that even with a forester jig set up, the drill will walk a tad..and all of the new made Redfield and the Gibbs bases need to be bent, ground or adusted in some way to sit right.
i havent had any issues mounting a Denver made Redfield base.
the qualty of the China made Redfields has gotten better, and ill mount them now, but wont mont the Gibbs made bases.