Problem Statement : I purchased a B. Rizzini, 20 Ga., O/U shotgun - but, failed to definitively pattern the gun for barrel regulation before the warrenty expired. Now, after careful testing, it appears that the upper barrel's point of impact is approximately 16 inches higher than that for the lower barrel at 40 yards. The lower barrel's point of impact seems well aligned ("centered")at 40 yards with the "normal" site picture. This differential in the points of impact for the two barrels appears to be unacceptably large.
There appear to be two possible solutions.
1. Connecticut Shotgun (who represents Rizzini in the US) gratiously offered to provide new barrels at their cost plus the action/barrel fitting fee. But, I have no response to my inquiry concerning the specification for regulation of the new barrels which can be anticipated or guaranteed. Do other members of the forum have information / standards / specifications for point-of-impact barrel regulation which can be expected from "good" double guns? I understand that perfect superposition of the two patterns of a double gun is unrealistic - but, what is a reasonable expectaion for the differential in the points of impact for the barrels?
2. I contacted Briley manufacturing with respect to the manufacture of compensating, screw-in, chokes to correct the point of impact problem with the upper barrel. In this case the bore of the choke is angled with respect to the barrel bore to compensate for the barrel's misalignment. Briley seems confident in achieving a good technical solution to the problem. In my opinion the required compensating angle may "push" the physically possible, choke geometry, modifications.
Do other members of the forum have experience with this type of compensating choke modification? Are the patterns created by these compensating chokes as good as those produced with standard, uncompensated, chokes?
Thanks for your help with these questions.
Don Henderson
