I am not an advocate for switching barrels around, but I have done exactly what you want to do except its been over a range of Savage Receivers for bull barrel target rifles (30-06, 308, 7.5 Swiss and a 6.5 Lapua on Order)
One of which is a mid 90s era 110 receiver that was 30-06 (and still is). My best gun. The older Savage actions are smoother.
A true switch barrel rifle does not require head space checks and a screw in Savage, Remage or any other barrel does.
Where it matters is not a bad setup but if you size cases and then a bit off on the barrel set, your cases may have too much shoulder (dicier if you do minimum shoulder bump).
Actually I am in that position, when I built the Savage 06 Target I got the chamber a bit long. No issue as the ammo fire formed fine and its good now. But I have eaten the throat out with all the rounds and I need to move it back (as well as extend the COAL out). I have to see how many rounds I have to resize of shoot up if I do that.
The good part of this is you can do all the work yourself and the tool costs are one time so it spreads over each gun and I am down to $35 or so.
You should get a head space gauge (GO Gauge) for each caliber. Yes you can do it with a shell case but its harder and not worth it.
You do not need to get a No GO. You put a piece of tape on the back of the GO and it moved it out .004 or so and that is a NO GO length (close enough). The only reason I have a couple of the sets of those GO/NO go was I was given them.
For me that was handy in 06 as I shoot Mil Surplus 06 in two models and it gives me data on what the chamber is like (A Model of 1917 is quite long, almost Field Reject and the cases for it are always kept separate)
Norther Shooters Supply has the best Barrel NUT Wrench and best setup ACTION VICE you will fine and you should get both. You should have a bench vice for this, 6 inch plus.
The Barrel nuts come off easy or are extremly diffuclut. The issue is the facory does not clean the threads and they have left over cleaning media in there. When they put on it gets crushed and its a luck of the draw as to how hard it comes off About 30% come off really hard.
New ones have no segment. those need a pipe wrench or to be cut (very very carefully) off. NSS offers a set of nut and the recoil lug. If you are going for accuracy its worth it.
You can get a breaker bad (the NSS tool has a 1/2 inch squire cutout for that) or you can brace it well and pop it with a wood piece (2 x 4)
Yes I use NICKLE Anti Seize on the threads. Some shout no. I am a former mechanic and I know a hell of a lot about joints and they do not.
I did use a torque wrench to set it to 50 lb the first few times. I have the torque wrench though. Not every one has one let alone a mechanic quality (not the pointer type). Now I have the feel I do it by feel. Coin flip there. Good torque wrench is not cheap. Low cost pointer one is an ok guide and it would be good enough but would get you laughed out of a mechanics shop!
If you do use a torque wrench, set it at 90 deg to the NSS nut tool. If you set it up so it adds length you are messing up the leverage values and there is a formula you need to use as you wind up with a lot more torque. 90 deg avoids all that.
Some claim 100 lbs, pwah. NSS has it right and the Action Vice lists all of that. I am guessing that the 100 lb type took a Savage nut off that came hard and figured it needed to be that. You need to look at all the factors not blind obedience to a single nut job (pun intended)
When I took them off I saw the remnants of cuts in the threads, crud equal bad torque. I thought at the time they used loc tite (someone toured the factory and saw that they wre not cleaning off the polishing crud, hmmm).
Barrels: If you hare hunting EA Brown has adequate barrel. I target shoot so I get good barrels. I like Shilen. Criterion is also very good quality large make for the non cut rifled type (they use buttons) I am waiting 4 months for my new 30-06 barrel. That is a custom bull for target shooting but my 6.5 Lapua I am building is the same time off.
Barrels now come in contours: Sporter is the modern thin one, they you have a heavy hunter (more like the old solid barrels) then a varmint which is about 3/4 at the end and then a bull barrel that is 1 inch front to rear.
I don't like the thin ones, anything normal is accurate as the bull. The bull sits solid on bench rest and does not move around easily so its biggest plus for stability . It also heats up slowly. Equally it takes a long time to cool down.
Cut rifled barrel like Lilja will be 8 months off maybe longer.
You have two thread sizes you will be asked about. Yours will be small shank or standard (two terms the same)
Savage came out with a slightly large diameter thread for short magnums and it has worked its way into the magnum line. They were having problems with the standard thread. Should not be an issue with an old gun or even an old magnum.
Action Lengths: There is Magnum, standard (30-06 case), medium (308) and short (223).
Each has its own bolt head size. You need the right length actin for the round you plan on (you can shoot 308 in a 30-=06 if you single feed) but not visa versa as it jams in extraction .
If you go exotic like I did with the 7.5 Swiss, you grind out a 30-06 bolt head as 7.5 Swiss falls between a 30-06 base and a magnum base. No issue. Most cases parent off 30-06 or 223 or the larger magnums.
Stocks: My best stock is a Savage Thumb Hole Featherweight. Boyd's is the supplier, its the stock I got for the 6.5 Lapua Target build. The original is on the 06 it came on still (Savage factory offering) and its a great target stock oddly.
Boyd's has a very good fit though they are not aluminum block bedded.
In my case I put on bull barrel and I had to sand out the space for free float. It can be done and it still leaves plenty of meat up front.
You do have to take the scope off to change a barrel, so you have that to get back on target.