doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Problem: O/U Barrel Regulation

Don,
I think you may have revealed the problem. My recollection, though only from memory of having looked at O/U gun barrel convergence yrs ago, what that the lower barrel should 'point up' more than the upper. The rationale I came up with this was that the upper barrel has more effect on muzzle lift during recoil. I think you can check this out on a Kgun or Rem 32/3200 pretty redily since they don't have side ribs.

I'm thinking your choke bore/threads in the barrels should not be parallel. I'll check some o/u's of mine tonight.

16 inches of slope in 40 yards is a deviation of about 3/8" in 30" barrels which I would think would be easy to see looking at the barrels. I mean that centerline of the muzzle end of the barrels is 3/8" wider apart than the breech end centerline. Even an old Californian that liked Labradors could see it.

I got into a long and disagreeable discussion of this problem of non-matching POIs over on 16gauge.com. Once on a gun built by ROTA and once on a B. Rizzini. I believe you can peer down the barrels all you want to but the only way to tell where it is going to impact for you is to shoot it off hand at a pattern board.

Earlier in this thread Chuck pointed out the theory on side by sides was that the converging barrels effect on POI would be offset by the assymetrical recoil of the barrels. If the barrels on an 0/U were parallel the recoil on the top barrel would cause it to shoot higher than the lower barrel using the same reasoning. The moment arm to the shoulder anchor is longer on the top barrel than the bottom barrel.

And if Andre the Giant shot the gun I believe he would get different POIs because his hand is much heavier than Don's. This difference along with Andre's heavier shoulder mass would change the dynamics.

I do believe Don's barrels are defective though. What do you get when you cross an elephant with a rhino? Elephino!


Best,

Mike

Here are links to the threads I talked about:

http://www.16ga.com/forum/viewtopic.php?t=1707&highlight=barrel+trouble

http://www.16ga.com/forum/viewtopic.php?...ght=fillibuster

Best

Mike

Chuck --

Please let me know what you find in evaluating you gun.

I heard briefly from Briley. They found my letter of inquiry a little overwhelming. They are working on the response.

In all -- I really think that a gunsmithing group that develops an effective, low cost, reliable solution to the manifold, double gun, point of impact, patterning problems -- will "make a mint". But, this will require -- that their solution becomes widely known and -- that the public takes the time to understand what they actually own for "shotguns". Perhaps, the Eyster group has arrived, "technically", already. I expect that Briley could, also, quickly join that group. But, the public may be substantially in the dark. This last point is the one that needs correction.

We'll see. Interesting.

I will be away for a few days -- my eldest daughter is getting married on Saturday.

Best Regards,

Don

Mike --

I found the first of your web references (in your latest posting) very helpful, indeed. Very educational.

I would like to thank you for this effort. Your first web reference sheds some considerable light on this thread and the B. Rizzini, point of impact, patterning problem -- since the required convergence of the barrel/choke axes - in the gun in question - appears to be absent.

Thanks very much for your help in this matter. Appreciated.

Best Regards,

Don

I'd try different choke tubes and shoot the gun off a solid rest.

All -

I received an e-mail a response from Briley. At least the Briley organization was forthright and did noy "over-promise".

Please see attached note from Ted at Briley.
---------------------------------------------------------------

We have read and discussed your very well written letter.

These barrels should have gone back to the Manufacturer. This is not an "out of warranty' issue.

Briley and it's gunsmiths pass on this project. You are correct. (given the amount of correction I am worried that the necessary choke geometry for compensation may "push" the physical limits of what can be done without overly thin choke wall thickness in some areas of the chokes)

The deal breaker of course is moving the POI ....16 INCHES.

The other is using the word "guaranteed by Briley".

Although we appreciate you contacting us regarding this project, it is my opinion that we would not be able to undertake this project and satisfy your expectations.

Please feel free to contact us in the future with a more doable project.

Ted

Best Regards,

Don

Don you are very welcome.

Best,

Mike

I just checked my Beretta 682 Gold E 32" bbls for convergence. Near as I can tell, there's about .160 convergence over the 32" length.

I'm now teaching my Lab to poop on Texan's boots.

Don,

Hope the wedding goes well and the barrel issue, too. If you fail to get it resolved my suggestion would be to get rid of the gun and move on. The barrel regulation problem does indeed exist, in most brands. There are exceptions, however.

One alternative would be to get a Perazzi, if you really like the style and handling of the Rizzini. I couldn't afford a new one, and really wanted to shoot one in registered sporting, so looked around until I got lucky. Fact is, you can fine very nice MX-8's, old but sound, for the money you've got in a new Rizzini. And you will not have regulation issues with them. In the last 10 months I have gotten two, one at $1850 and another much newer and probably a 98% gun for $3400. Both with 31 1/2" barrels and both tight as a drum. The last one still has to be pushed down to open. K guns will not have the regulation problems either. I just like the Perazzis better.

Good luck, Stan