Am I the only one who thought this thread was going to be comparing the Mosin-Nagant to the German K98? You know, Russian vs Axis Power rifles?
Seriously: for what you describe, the most cost-effective decision, with the highest potential accuracy, in the most re-sellable package, is to buy a modern rifle in the caliber you want.
If you WANT to do the conversion because you want a one-of-a-kind rifle that reflects your skills as a gunsmith, then you can use the Mosin-Nagant.
However, it would probably add
at least $500 to have it done right, plus the cost of the rifle itself, as well as the scope. This means probably closer to 7-800 to make it as nice as you can.
You would need to:
And you know what? After all of this, that Savage Axis will still be cheaper, as well as probably more accurate and with the same or better trigger feel.
If you want to do the labor, for some reason, that is fine. I did something like this [other than re-chambering] to a 1895 Chilean Mauser that has been in the family [in sporterized condition- I didn't start the ruin] since about 1962.
It is a family heirloom that shoots a very respectable hunting round for deer and smaller game. It does everything I want of it. If I want more power, then the family '03 comes out as the 30-06 is good enough for whatever the 7x57 is borderline for, for me. I won't hunt griz, or elephant.
Now here is a different thought:
Buy the Mosin for a brush gun at distances under 150 yards. At that range, the M39 or M44 will have about as much knock-down power as a .308, if not more. Add a different safety, and leave it alone. It is what it is.
THEN, buy the Axis for long range work [target or hunting].
Just don't try to make a classic muscle car into an Indy car- the amount of money it requires to make the change isn't really worth it.