Barrel Convergence Issues


Hi. Bruce

The question I have is do you know of any gunsmiths that will try to correct this problem. This past spring I went to a Browning 525 32″ barrels when testing gun I noticed the bottom barrel is dead on, the top barrel shoots high, and it drives me crazy.

My friends suggest to go to a Beretta o/u, but I love the feel of the Browning. I’ll be awaiting your reply.

Thank You.

Ronald

Dear Ronald,

It is very common for the top barrel of an O/U to shoot high. Most, or at least a great many, do. Part of it is due to the fact that the top barrel is above the central axis of the gun and recoil upwards more than the bottom barrel does when the gun is fired. This can vary slightly with the strength of the shell being used.

The other part of the problem is that perfect barrel convergence usually requires individual checking and hand regulation. Mass produced guns like your 525 won’t get that kind of treatment. The makers all set their barrels on jigs and test the first few barrels for proper regulation. Then they assume that if the jigs don’t move, the subsequent barrels will remain in proper regulation. That approach sometimes works for a while. Don’t feel bad. I’ve seen Belgian Brownings and Perazzis with top barrels that shot inordinately high too. Paying more doesn’t always get you more. The only shotgun guaranteed not to have barrel convergence problems are single barrel guns.

The fix? With fixed choke guns, it’s easy enough just to regrind the offending choke on a bias and you can pretty much move the pattern any where you wish. I had a Parker Repro 28 two barrel set. The left barrel on one set shot waaaay to the left. It had a full choke, so the gunsmith had plenty of metal to play with and he was able to grind away enough on the inside to move the pattern back where it should be and still leave a fair amount of choke performance.

With fixed choke guns you can also send them to Briley and Briley will install Thinwall screw chokes on an angle to correct misconvergence. It’s amazing that they can do such a subtle installation, but they can. Just tell them how much the offending barrel is off and when they screw choke it, they will put the threads in at a very slight angle to correct it, yet they will still be using normal concentric Thinwall chokes. It’s quite marvelous.

Guns with factory screw chokes like yours are a different deal. I guess theoretically it’s possible to separate the barrels and then resolder them, but it’s probably not worth the effort and expense. Another approach would be to have Briley make you custom eccentric chokes for the top barrel. They will do that if you ask. Of course, the chokes have to be perfectly indexed each time you installed them. A third approach would be to permanently solder a set of chokes in place, making it a fixed choke gun, and then grind the top choke eccentric to move the pattern.

Or you could sell the gun and start again.

One of the big advantages of buying a used gun is that you can you have a three to five day inspection period to test for things like barrel convergence problems. You can’t do that with a new gun. Something to think about.

If you sell the gun, don’t think that you have to switch brands. The next Japanese Browning you buy might be just perfect and the next Beretta might be off. It’s a sometime thing. Most people never check for barrel convergence problems, so many never notice it when they have the issue.

Also, it’s a matter of degree. No two barrel gun puts both shots in exactly the same place once you get to fooling with different strength shells. There is always a little variation. The bugaboo only arises when there is unacceptable variation. A few inches at target distance won’t matter, but a foot will. You can’t expect convergence perfection, but things ought to be sort of close. How much mis-convergence you tolerate is up to you. I think of things in terms of a two foot effective pattern. I really wouldn’t want to give up much more than six inches of that. So I’ll tolerate barrels that are up to six inches out of convergence at the distance at which I shoot the targets the gun was designed for. Your mileage may vary. Most makers would to back flips if they could consistently keep their barrels within six inches of each other at 40 yards. Few can on every set of barrels.

But here’s a piece of good advice for most shooters: If you already have a gun that you shoot well and are happy with it, DON’T test it for barrel convergence. It’s like going to the doctor’s office when you are feeling fine. You can only break even or lose! You can’t win. If the gun shoots well for you and you test it for convergence, it will either be fine or it will be out of convergence. If the former, you are not better off than you were before. If the latter, you have just taken a gun that you shot well and consigned it to the junk pile. You’ll never be able to shoot that gun again without thinking about the fact that both the barrels don’t shoot to the same place. Sometimes blind faith has advantages.

On the other hand, if you seem to miss more with one barrel than with the other, then maybe it is a convergence issue and you ought to look into it. Ronald, you did just that and, though the answer wasn’t one you were happy to get, at least you now know where you stand and can do something about it.

Best regards,

Bruce Buck
The Technoid writing for Shotgun Report, LLC
(Often in error. Never in doubt.)

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