I also thought of a possible different approach.
Montana action $800 + benchrest barrel $300-$400
= $1100-$1200 and then just get a stock
I guess plus the cost of gunsmithing to fit the barrel to the action.
?
I would rather get the M70 and rebarrel, probably similar cost since you have the walnut stock and it is a real M70 plus you will have the island sights of the M70 barrel.
Even better is get the M70 and just shoot it
