ORIGINAL: bigbulls
2) First part... no. Second part...yes if it is a pre64 receiver but you would have to likely set back the shoulder, rechamber, set back the breech face, and recut the extractor cut in the breech face.
You would still have to do this if it was a pre-64 barrel on a pre-64 receiver? My thoughts behind getting a .30-06 barrel is it would be less expensive to shoot, and I wouldn't be wearing the original barrel out, and .25-06 is based on .30-06 so I would think if I was using a .30-06 barrel I wouldn't have to change anything beside the barrel.
If I sound stupid it probably has to do with me being 19, from an anti-gun family, and having only a .22 Savage and a Remington 870 to dabble with as of now.