Re: questions about accuracy for savage swap barrel
I don't think I'd have any work done by these guys. It just sounds like they're trying to stick you with more work to be done. Like the others have said, there are plenty of super accurate Savages out there using the nut. That's part of what makes the Savage such an easy platform to build off of. And the greatest benefit of the floating bolt head is that it doesn't need to be trued.
On top of that, $540 sounds like an awful lot for a barrel from a lesser known manufacturer. They might be great, and they should be for that price. But you can get pre-fits from Shilen, Douglas, PacNor, Lothar Walther, Brux, McGowen, and others for around $350. These are proven makers that have a lot of happy customers, and some have more than a few match wins to their credit.
I've never had any trouble getting a Savage to shoot accurately before or after a barrel swap. When ever I get a new rifle or barrel, I just set the head space so that the bolt just closes on a Go-Gage. Then whenever I want to swap barrels, I just set the head space to the same Gage the next time I install the barrel, and I've never had any trouble. All of my Savages shoot at least .5 MOA before and after a swap. And that's good enough for me.