If it's a barrel regulation issue, changing the cast will change the POI of both barrels. You can't change the POI of one barrel only by adjustments to the stock.
No arguement. I agree. But sighting down the rib at a target should result in both barrels hitting equadistant from the aiming point, IMO. Then I could successfully adjust regulation of the crossfiring
Bending the stock from "cast off" to neutral will move the POI to the left for both barrels.
My theory is that it will move POI right.
If the left barrel is spot on, and trigger pull on the right barrel is not an issue, you might want to consider letting Briley put choke tubes in the right barrel only that will alter the point of impact. I think they call them "eccentrix" choles or something like that. I had to do that with an AYA recently for the same problem.
Certainly a POI can be changed by an eccentric choke. But there are almost always more than one way to do something. If the barrels are straight and the chokes bore correctly, my feeling is that it would be a stock issue that the POIs are not the same distance from point of aim. Any crossfiring or opposite would be a convergence regulation issue, IMO.
There are I think two aspects to consider here. As Hack has said reducing the cast will tend to make the gun point more to the left. On the other hand changing the pivot point (shoulder contact) to the left will tend to make the gun shift more to the right in firing. Which of the two will hav the greater effect is hard to say & in either case will affect both bbls.
I am assuming though the owner thinks he can live with the existing seperation, just wants to have the "Center" of the two impact zones on aim rather than to the left side.
Miller, I thought I'd get it shooting the same for each barrel first, then either deal with the crossfiring by one of a few methods or decide if it's acceptable.
I'm aware of methods of working a choke by hand to one side or the other. I'm not eliminating that, but I'd like to get this asymetric POI issue assessed and addressed first.