over/under barrel alignment problem

[ironhorsemanfxsts]

I bought a Franchi Diamond 12 gauge over/under used that I have been using to shoot sporting clays with. And my game as really been suffering. I was using a Win. 1200 20 gauge and decided to get serious and upgrade to a higher quality firearm that I didn't have to chase my spent hulls across the field for my reloads. I finally done a pattern test with the various chokes at diffrent distances, and found that the bottom barrel is shooting about 18" lower than the top. Can this be repaired cheaper than buying a new firearm or am I just out of luck.

 

[Bradsknives]

There is a tendency for the top barrel of an O/U to shoot a little higher than the bottom barrel because the top one is farther above the line of the recoil, and there is a little more muzzle rise. That tendency could be compensated for when the barrels are made, but it usually isn't because the effect is small and varies from one shooter to another.
2 1/2 to 3 inches at 40 yards is as close as it needs to be. A shotgun is not a target rifle. 18" is way too much of a difference. I know that Browning tolerances are; the top barrel can be 3" high, the bottom barrel 3" low... which gives a 6" spread between barrels.

This sounds like a bent barrel problem to me. You need to take it to a gunsmith and have it checked out.

One other thing to keep in mind ...if your shotgun has screw in choke tubes, it could be due to a choke tube installation that is not centered in the bore. You can inspect your barrel for this problem by looking in the muzzle end (barrel removed, of course) and inspecting the choke's seat at the end of the milled area. Since the bore is always a bit smaller than the opening of the choke tube (this for obvious safety reasons), you will be able to see the edge of the bore right at the end of the choke tube. This edge must be of even thickness all the way around the choke seat if the choke tube has been installed on center. I can't believe if this was the problem you would have a 18" difference...probably more on the lines of 6" to 8" difference.

 

[6birds]

Chokes, good call Brad, easy to try.

 

[451_Detonics]

Not really a "bent" barrel but rather a set of barrels that weren't properly regulated. It would like have to be a factory fix as the spacer between the barrels will have to be changed, the barrels will have to be de-soldered, regulated, and the soldered back together. The barrels should converge at about 60 yards before and after that they will shoot apart but 18 inches is a bit extreme to say the least.

The other option is called choke regulating where slightly off center chokes are used to regulate the barrels at a set distance, cheaper than having the barrels regulated but also not as effective.