Jim,
There was not much standard about the way they were made into drill rifles,some may have used stainless and some didn't.Some had holes burned into thr botton of the barrels(in chamber area), some had rods welded into chamber and some had rods forced into chamberend of barrel, but not welded (I removed several for a friend that needed the barrel dates).I have seen quite a few of these actions put back into service. They seemed OK, but were mostly 03-A3s, because the A3 barrels were on hand.
Mike