UPDATE ...
Well the last week wasn't much fun.
- Soaked the action/barrel interface for days in Kroil penetrating oil.
- Used a Bugholes internal Tikka action wrench ... no go.
- Used a NSS external action wrench ... no go.
- Torched the action to heat and expand it ... no go.
- Froze the barrel to cool and shrink threads ... no go.
- Torched and Froze ... rinse and repeat ... no go ... won't budge.
I've got two great barrel vises (MechForce and Davidson) ... both hold the barrel super tight so that it doesn't rotate. I weigh a biscuit or two over 240, and with all my weight on the action wrench (either/both) and my feet basically off the ground, the action won't budge. Tried hitting the wrench(es) with a BFH and that didn't work either.
I'm convinced the Tikka factory torques these on using a gallon of superglue, and a two-story lever being pulled tight by a team of a half dozen large elephants chasing a dump truck full of peanuts.
The barreled action is now on it's way to LRI in Sturgis, SD ... where "money" will solve the problem I can't solve with "muscle". I officially give up.