doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Gun reboring and regulating.

I had a similar experience as Joe. A Belgian Janssen et Fils 3" 12ga I got for waterfowling was giving me fits until Tom Hall and I patterened it. The chokes had been opened a bit from the extra full they like to put on these guns it was done badly, the gun shooting about 2 feet low and right from the right barrel, not much better from the left.

A trip to Mike Orlen put it back in regulation, he was able to straighten out the chokes while opening them a bit more. Now I actually manage to shoot ducks and brant with it. The gun was badly regulated.

Eightbore and I believe that side by side barrels are curved in the horizontal plane, like two bananas back to back. My shooting student Joe Wood reports that the gunsmith at Skeets stated that side by side barrels are curved, referring to the curve as "English".

A thread on the Parker board I started on the subject: http://parkerguns.org/forums/showthread.php?t=12251&highlight=swamped

Thought provoking point Mike, but I think that link just notes that the center line of the two bores converge at some point or another in the muzzle direction. It doesn't seem to show if there is any curve in the bore between the breech and muzzle. I'd still suspect the point where a gun bore sights to and where it patterns is probably different, and maybe it should be patterned with a hold that's similar to how it will be used.

I wouldn't put up with one that bad either, Stan. Maybe you and I have been on opposite ends of the "luck" spectrum in this regard. Nice to know I'm lucky in some things!

AmarilloMike and I have been back and forth on this subject for quite a long time. I did tell him what comments one very good barrel man had. However, he did not say all were done, just that he had run into it and before doing any choke work he first determines if they're straight or not. If not, he pilots the choke work from the muzzle. I have a hard time believing the vast majority of builders did anything but "regulate" straight tubes while in the jig and ready for soldering the ribs on. And usually they got it very close. It is just beyond credibility to think the guns were taken to a shooting area and shot for POI and then ribs loosened and barrels moved, etc. I mean, does anyone really believe that when Ithaca was making a couple hundred thousand Nitro Specials they did anything like "regulating"? Comm'on.....or, how about many Spanish guns that have the ribs brazed on. The only way to remove the ribs is with a hacksaw.

Joe, obviously the barrelsmith believed that they were deliberately curved, not just a factory defect or poor workmanship. I don't know that that is clear from your post.

Even if Ithaca didn't regulate the Nitro Specials it doesn't mean they didn't regulate their Sousa Grade double trap guns either. Same with Parker Trojans and Parker AAHE pigeon guns. Same with Sterlingworths and Fox HEs.

Maybe they were intentionally curved, but I believe there are references in historical writings about how shotgun tubes were evaluated for straightness and corrected. It wouldn't surprise me though if the uneven heating and attachment of a rib system might not distort some curve into finished barrels. I'd think depending on the gun enough was invested at that point to not worry too much about it, but probably good to be aware of if it needs barrel smithing later.

I surely don't know enough about sxs guns to argue with any of you gentlemen, but I will report my recent experience with a Spanish gun. It was made in the 70s, but still very tight when I bought it, like it had hardly been shot at all. The triggers were nearly 10 pounds, so that was likely part of the reason that it hadn't been used much, but the barrel regulation was just awful.

The left barrel shot way to the right and the right barrel shot way to the left. If you had shot at a stationary clay target at 30 yards, you wouldn't have touched it with either barrel. I can only imagine the frustration that shooters had with this gun trying to hit flying game. I bought it hoping to make a turkey gun of it, but thought that impossible after patterning. And it was consistent with every load I tried; left barrel shot to the right and right barrel to the left.

I didn't pay a lot for it and told my son in law that I was gonna leave it at our camp for a gun to shoot the occasional varmint; just remember which side to aim. Then a guy on another forum told me how to file the chokes to move the patterns. With nothing to lose, I decided to give it a try. I started removing metal on the outside of the left barrel to move the pattern back to center. It was only after removing about half the metal at the very end of the barrel that the pattern started to move, and then it moved quickly. I got it close to center for my field load, and then did the same with the right barrel.

When I tried my heavier turkey load, I found that the left barrel was perfect, but I had gone too far with the right barrel for the heavier load - it now shot to right. I had no idea if I could undo what I'd done, but gave it a try by doing a little filing on the inside edge. Just a few licks with the file and the right barrel was centered.

I killed a turkey with the gun this spring, and it centers well with both barrels. However, it will only center the heavy turkey loads. Lighter loads are still off a little, though much better than before. It was an interesting project.

coosa that is great information and a great post. Thanks!

Chuck H. also reported that he regulated a 410 by filing the "chokes" to center the pattern.

The Barrel drawings in the L C Smith Plans & Specifications show the barrels set to converge at a definite angle. They also give the breech spacing & the muzzle spacing, the pint where the extended axises would cross & the distance apart the extended axises would be at 40 yds. It is "Extremely" easy mathematics to calculate that all dimensions are worked out with "Straight" bores. If a barrel is curved to any extent at all you can "SEE" it with the naked eye from either the inside or outside. I acquired my first double in 1954. In 60 years of looking at double barrel shotguns i have "NEVER" seen one from a JABC up to some much higher grade guns than I have personally owned & have yet to see one with the barrels swamped in like two Bananas back to back. "IF" you have such a gun please do take some good pics of it, take measurements of the barrel diameters at regular intervals & then the width across their outsides at the same intervals & post it all. In other words "Put Up or Shut Up". Double barrels simply are "NOT" assembled in that manner.