If you were to chamber sleeve a 12 down to a 20, how would that effect pressure issues? I guess it would be the same as using chamber-mates or similar gizmos, only permanent. Presuming that pressure would be significantly lower in the increased volume of the 12 ga tubes, and presuming that proper 20 ga shot-cups would seal the bore for the step-down(up), and presuming that the 12 ga chokes would still be effective, would this be a workable way to safely shoot modern 20 ga loads in old damascus 12's?...Geo
