The main beef about the nut is how it looks. Too many rifle purist find the Savage action ugly. The nut is arguably a better way to lock the barrel to the action as it puts no strain on the barrel itself. This is really splitting hairs.
The way Savage designs their mags, all cartridges in the same family use the same mag. So the 308 mag also works for the 22/250 or 243. You'll see when you hold the mag. A very nice setup that accomodates case dimension differences very well.
Where do you live? Might be easier then you think to sell off the stuff.
There are some in the US that get or strip rifles for their action. I don't think Savage does that factory direct. For me, the best way is to buy a Stevens 200 and sell off the parts. Even if I didn't, the rifle is so cheap, I couldn't buy a used Rem 700 for the same money.
You will need a barrel vise,I use a 5" bench top vise with shaped blocks of hardwood), a nut wrench,available from Brownells or ebay), headspace guages, and a large rubber mallet.
Clamp the barrel, loosen the nut with hammer and wrench, spin off old barrel, spin on new barrel with nut, set the headspace, tighten the nut. Recheck headspace and you are ready to make noise.
Do a google for Adams and Bennett barrels. They have step by step instructions for barrel install with pics. After you do the first one, you will wonder why other rifles don't use this same install.
Then the real problem begins. Spending way too much money on all sorts of barrels, then bolt heads, stocks and accessories. A standard barrel shank long action can be set up to shoot the 223 all the way to a 458Win mag just by swapping parts.
Fun, fun, fun...
Jerry