I have a nice 1903 Springfield action that I am turning into a .338-06. Only hiccup is that a previous owner drilled and tapped the action for 8x32 scope mount screws. The action will get custom scope bases and the holes are aligned and in the correct locations. My question is whether this is worth trying to correct, and if so, how to correct it. The holes in the rear bridge could be welded up and redrilled, but what could be done for the front receiver ring holes?

Use the 8 x32 try them and see what happens if the hold and don't shoot loose I would keep them

Probably repairing some 6-48 that were done wrong. Use them with Loctite and move on..

Yeah, if it works, why bother? If it ain't broke......

Some of us including myself with many years of experience fitting scopes to rifles, have never experienced loose or broken screws and bases, that is because we epoxy glue the bases to the receiver and also epoxy the screws into their holes, despite the misgivings of some who question how you can remove the screws and bases in the future without marring the finish (simple and no marring).

I have more things to think about when hunting than to be concerned over whether my scope bases are tight or screws are not about to let go.

Glue your bases and screws and forget about them.

The rear ring is what concerns me. It is very thin on an M1903; you probably only have two good threads with 8-32.

But try it as is. If you have a spare mount you can return the rear at least to 6-48 or 8-40 if you don't.

Solder the base on and don't worry about the screws.
Or glue it on; that will work.

Loctiting or using finger nail polish or any other glue on the base screw threads alone may stop the screws from coming loose but they can still be pulled loose and stripped out. All the recoil stress or even just handling stress (carry rifle by the scope) is on the scope rings transferring to the bases and thence to the screws. Soldering (steel bases) or gluing the bases takes away the stress or a very high percentage of it from the screws. That is, the stress path is mechanically interrupted when bases are soldered or glued.

Considering we spend a lot of money on developing great loads, put great glass on our rifles and tweak and fiddle to get the best accuracy possible, I don't understand why there is debate to gluing bases, other than we like to debate

Yes, I was talking about actually epoxying the bases on; not just on the screws. In this case, I would use solder. Easy and definitely won't move. I just soldered on some bases on a Mauser; didn't even have screws.