Originally Posted by Parabola
My WAG is that re barrelling a side by side would be at least 25% to 35% for the current new price of a similar gun.

I think Parabola's estimate is on the money. Ten years ago I was looking to order a Spanish sxs from the factory, with an extra set of barrels. The premium for that extra set of barrels was 35% of the price of the shotgun itself.