The Mosin is worth haveing, its an accurate rifle.
I wouldnt "sporterize" any Mosin, I collect them, and the wood has a use in the deep cold, as well as protecting the rifle too.
The M-38 is going up in value and is handy as it is. You can find mods, and if thats what to gonna do, then the 91/30 would be more appropriate.
Mosins are VERY accurate, and modern surplus from the 50's onward is just fine. I use 50's Czeck and 70's Russian light ball , and I get 200 yard 2 inch groups easily, with My M-39 and my M91/30's.
The highest scoreing Snipers in the world used Mosin Nagants.
Olympics medals have been won with the Mosin Nagant
I wouldnt lighten the rifle a bit, it is a Mans rifle, and the weight makes the balance and reduces felt recoil.Takes a man to carry one, but pesant Russian boys did fine.
There are MANY "hunting loads" on the market now, Google "7.62X54R hunting ammo for sale" and see.
If your rifle has a bad bore and is rusty from the corrosive ammo, then who ever was shooting it didnt clean it properly , like a Russian Pesant did, in the mud, snow and summers dust of WWII.
Corrosive ammo is easy to clean up, just use hot water to dissolve and flush the salts with, it drys itself, then clean as you would regulrly, brsuh ,slovet, patches, oil.....
I shoot to 400 yards on Caribou and such because im on open Tundra and can see for miles, which means animals see me too. I can shoot much further with theopen sights, but that pretty rare and mostly for Wolves.
Only accurate rifles are interesting, and the Mosin is very interesting.
You can find trigger mods and cleaning tips, as well as reload brass for an exceedingly accurate rifle, here and at "gunboards.com"
If your 30-06 aint feeling right annd a Mosin is, thats the way to go, but be sure the bullets go where you want, thats what its all about.
Good luck.