Usually I tighten the barrel nut to 40 ft lbs, with a torque wrench. Use an anti-seize. I use Shilen, Brux or Pac-Nor barrels.
I'm almost bankrupt from these Savage's. Wife complained about them, so I changed to building Remingtons with the Savage style nut. Now I'm in the dog house.
Here's the partial collection from a couple years ago, did I mention how deep in the dog house I am?