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I've posted several times about the importance of straight, well regulated bores on double guns. I just encountered another crosseyed Italian double, this one a ROTA made for New England Arms some time back and sold to me by Cabela's in Dundee, MI as new in box.

I ordered this little 28 ga. double last week. I asked at the time for a knowledgable staffer to check the bores for straightness before shipping. Naturally, this was not done. I'm betting that none in the gun library had a clue what I was referring to, so they just shipped it on faith. Bad Move.

Upon receiving it, I immediately sighted through the barrels and found the right barrel curved badly to the lower right and the left barrel curved slightly to the upper left. This one would shoot to a common point of impact only by a miracle. The patterns from the right barrel would also be lopsided. Back she went. Its a shame. The gun was well finished and a nice looking piece. But as in all things, looks will not offset poor performance. What a waste of effort by the maker. The gun is nothing more than nicely finished junk. the old timers referred to such as "lacquered trash." That about sums it up.

Given today's technology, tooling, and techniques, there is no reason any double gun maker can't assemble straight barrel pairs to shoot to the same point. It is just as cheap and easy to do so as not. The only explanation has to be that the barrel makers don't care about their work and the importer either does not know a good set of tubes from a bad one or does not care either. So junk like this ends up in the hands of the buyer. I see a lot of these pieces of scrap iron at gun shows. Probably the buyers get tried of missing and trade or sell them off cheap.

My best advice it to learn how to spot a junk set of barrels before buying or insist on the right to return the gun for a full refund if the seller varifies them as straight and they are not. The practice of checking every double gun you buy for proper bore will save you time, trouble, money, frustration, missed targets, and poorly hit game birds.

Member Joined: 26 Apr 2005 Posts: 743

Not that it's any consolation to you, Guy, but I've heard of similar problems from owners of a couple Rotas.

So as someone new to the doubles world - what exactly do you look for when peeking down the bores of a double - how can you spot the bows and twists?

Is it as obvious as a bent 2x4 at Depot?

what other things should one look for during an inspection of a double?

TIA

Its farly simple to do. The bore must be clean and shiny first. Now point the barrel at a neutral colored, evenly lit surface and line up the mouth of the chamber with the muzzle. You should see the muzzle hole inside the chamber walls and forcing cone ring like a circle within a circle, within another circle. Think of a bullseye target and you will get the image. Any curve to the bore will show up easily as eccentric reflected rings all the way down the bore. These rings will not line up well one evenly inside the other or the muzzle hole will not line up with the chamber, the forcing cone ring, nor the reflected rings.

Check both barrels for straightness first. If they appear reasonably straight, then turn the barrels vertically if a SxS or normally if an O/U. Now rest the barrel set on a stable surface, sight the top barrel on a distant mark, and center the mark smack in the middle of the muzzle hole. Next, without disturbing the barrels, sight through the bottom bore. The mark should be somewhat low of center and dead on the same exact vertical plane. There should be no difference left to right. However, the bottom barrel should sight a bit high. This is normal to allow for the affect of recoil and barrel time of the shot travelling its length. Also check the rib to see if its pointing where the barrels are. Its easy to do with an O/U. However, a little practice with an SxS will make the check just as easy. I just turn it horizontal and resight down the rib. Both right and left barrel should be toed evenly toward the mark and the rib wiull split the difference perfectly.

A straight tree, a fence post, sign post or a door frame make nice marks to sight on. You'll see any barrel alignment problems very nicely this way. An old cardboard box with a slot in two opposite sides makes a nifty barrel sighting rest. Most shops have something suitable laying around. A barrel cleaning rest works well too.

I do this to every prospective shotgun purchase. I even check single barrels for strightness and rib align ment. A straight, round bore throws very evenly didtributed patterns usually. A curved bore throws an elliptical pattern due to the centrifical forces exerted on the shot as it speeds around the curve plus the pattern will not hit exactly where the curved barrel is pointed. It will shoot wide be it up, down, left or right as the curve dictates.

A tiny bit of curve will not usually cause any problem as long as both barrels are matched for the amount and orientation of the curve. If this is done and the barrels are toed to sight toward each other a tiny bit, the gun will probably shoot okay for hunting. However, any easily noticable curve will keep the barrel from shooting true with a nicely rounded pattern. For target guns, only pick dead straight bores sighted to the same plane and toed in a tad.

Don't let any saleman or shop owner talk you into buying a gun with noticably curved bores, not at any price. Let the unwary buy them if the shop owner insists on selling it. Don't get suckered into this"bargain". It is anything but. Good luck.

PS: this matter of bore straightness applies to all modern mass produced doubles. Some of the better pre-WWI guns and many 19th century doubles with very slightly curved bores were regulated by hand to allow for any minor shift. However, only the best were and no mass produced guns are now nor ever have been regulated by hand this way unless it was to correct a severe problem after the fact. They have been assembled on a standard barrel orienting jig and soldered or brazed together as they lay. Any slight curve in a pair of barrels has to be marked and indexed in the jig to match prior to soldering or the barrels will not shoot together.

Many of the less expensive guns from Europe show this is not carefully done. An expensive price tag in not a guarentee either. I've seen poorly made barerels on some relatively exensive guns from both Italy and Spain and even a few on Merkels. So look before you buy or get a guaranteed 5 day look period it buying sight unseen off the net or from a marketing mag like the Gun List. If you don't, then you own it and too bad on you if its not a good one. The cost of fixing the problem is both expensive and not always possible.

Joined: 03 Jul 2005 Posts: 370 Location: Amarillo, Texas

When I get a new-to-me double shotgun I shoot each barrel at a paper target with a aiming point marked on it. I shoot several targets once each with each barrel. I then "judge" the center of the point of impact . I compare the point of impact to the point of aim. Since on a side by side the center of the muzzle of the barrels are closer together than the breech centers the barrels are curved in the horizontal plane. On a side by side, for whatever reason, the custom seems to be to leave the breech centers and muzzle centers the same distance.

Mike

Mike, once you shoot a new gun, you are generally stuck with it. I don't know any gun shop or sporting goods store that will take back a new gun once its shot for a full refund. So patterning a new gun only varifies what your eye can tell you first. Look the gun over carefully, especially the bores.

All doubles are supposed to toe in a bit. Perfectly parallel bores on a double, O/U or SxS will shoot away from each other due to recoil and the barrel time of the shot column. However, the bores should not be curved in as a rule. they should be straight as possible but toed in a bit at the muzzles. If you take two dead straight sticks and lay them out with a bit less space between one end than the other, you will get the picture.

O/U guns show a bit less toe, because gravity helps offset the muzzle rise. The bottom barrel is also more in line with the shoulder when its fired and tends to rise less than the top barrel.

SxS guns must be toed in a bit more, because the recoil forces work more on a horizontal plane than an O/U. Vertical shift is not an alignment issue with SxS guns as both barrels should recoil up about the same amount given that the loads being fired are also equal.

Orienting slightly curved barrels so the curves face each other at the muzzle might allow the pair to shoot to the same place. However, curved bores also throw elliptical patterns to some degree depending on the severity of the curve. elliptical patterns do not often show a clearly defined or predictable pattern center. Its just another added problem.

If those curved bores are not matched to each other, the recoil forces will introduce some amount of torque away from where the curve points the muzzle. This torque can and often does introduce unpredictable forces which can cause further alignment problems.

A curved bore also tends to be less round than a straight bore. Round bores throw round patterns. Out of round ones do not. More problems are introduced and more negative effects on the pattern and where it hits will result.

Given a round barrel, the straighter the center line of the bore, the better the barrel will shoot. Curved bores always introduce negative effects on the pattern and where it hits. These problems can be difficult or impossible to offset. My best advise is learn to pick a double gun with straight, well regulated bores by eye and avoid the problems curved bores cause.

Member Joined: 26 Apr 2005 Posts: 743

That is pretty thorough and darned good advice Larry. One or two other things might be added.

If you spot a screwed with gun or a bad one on a gun show table or in a shop, it says a lot about the dealer. Be very careful from then on around this fellow. Most good dealers will avoid buying crap or passing it on to customers unless its in the junkers for sale section and clearly marked as a fixer upper. Most good dealer will refuse to sell an unsafe gun to anyone unless he knows that person has the skills to fix it. Unfortunately, there are a bunch of dealers who would sell any old piece of crap for as much as possible as not. These guys are parasitic predators who think its just business as usual.

Which leads to another warning. a high price tag is not a sure indication of quality or soundness. Some dealers are just plain greedy. Others put high prices on their stuff and then offer a "big"discount to trap a fool into buying another junker at a good gun price. Usually the mark will talk himself into buying the gun because he's argued the price down to where he thinks he's getting a steal. Wrong. Used car dealers love this ploy. It works like a charm. Be smart. Look before you buy.

Joined: 03 Jul 2005 Posts: 370 Location: Amarillo, Texas

In my post above I wrote "On a side by side, for whatever reason, the custom seems to be to leave the breech centers and muzzle centers the same distance. " Instead of "side by side" I should have written "over & under."

What I am trying to say is that mass produced Parkers and many other quality SxS shotguns are made so the barrels fit like two bananas - back to back with the breech ends farther apart than the muzzle ends.

Usually when buying a used shotgun over the internet there is an inspection period - usually 3 days. I try to remember to make it part of the deal that I can shoot a couple of box of mild shells through the gun as part of the inspection. I have never been told I couldn't shoot the gun as part of the inspection.

Mike

I think we've been talking apples to oranges there Mike-- or apples to bananas. Laughing

I'm referring to mass produced guns made after WWII, especially guns made after 1960, not classic Parkers, foxes, etc from prior to 1940. I also specifically said new gun, not used in reference to not being able to shoot it to find out how good it is. I too would not buy a used gun without the ok to shoot it. This is not possible with a new gun in most cases.

Some of the old techniques used to assemble and regulate barrels are no longer used. Bending barrels to regulate a mutual POI is not generally done anymore. It was never the best way in the first place, just the easier way for some guns.

Gunmakers, the industry in general, and even the shooting public have come a long way in understanding what makes a gun shoot excellently since the pre war era. Most reputable makers now try to use only the straightest barrels they can make or buy. The benifits of straight barrels are far too many. Be they double guns or a single barreled repeater or trap gun, well made modern production guns tend to shoot much better, much more effectively, than earlier production guns. its not just the improved ammo either. The guns are just plain made smarter and shoot better.

However, this does not apply to all brands. I've seen some real junk being imported and farmed off as top quality at unjustified high prices. I've posted what I've seen. Let the chips fall as they will. If you are looking for a new or late model modern double, look for straight barrels first. Everything else is just window dressing if the gun will not shoot true.

PS: the best 19th century British double gun makers figured out the benifits of straight barrels back in the percussion muzzle loading double gun era and even before that. They found that round, straight, evenly bored barrels shot the most effectively with any given charge of black powder out to a farther range than any out of round or curved bore. The best barrels were reserved for the best guns-hence the term. It holds just as true today.

Guest

Very useful information.

Joined: 03 Jul 2005 Posts: 370 Location: Amarillo, Texas

All of this post is in reference to SxSs.

I was pointing out that curved barrels are not proof of a problem nor a defect. I used "new-to-me" in my second post about checking POI after some posts about inspecting used guns. Bending barrels is still the way the way top-quaility makers regulate their barrels - including Purdey. The only way to tell is to shoot the shotgun as I desribed. I appreciate your point that "new-in-box" guns can't be shot as part of the inspection.

The centers of the muzzles are closer together than the centers of the breeches on all the guns I own and it would appear (on average) sighting down over them that the right barrel would shoot 2 feet to the left (of POA) at twenty yards and the left barrel would shoot to 2 feet to the right at twenty yards. All these guns were made before WWII some before WWI.

How do you regulate the non-parallel barrels to shoot to a POA at 40 yards? One is to bend the barrels and the other is to cut the chokes in crooked. Briley makes and installs eccentric screw-in chokes to correct POA/POI problems. i have read a post that quoted Oscar Gaddy as saying that is how Parker Reproductions regulated the barrels on their guns. I just bought an AyA from Jack Rowe and the barrels are bent in the back to back bananas I described before.

I believe the guns you sent back could have been well regulated. I am not familiar with ROTA. The only way to tell for sure is to shoot them.

Mike

Joined: 03 Jul 2005 Posts: 370 Location: Amarillo, Texas

I apologize to 16gaugeguy for the terse tone of my posts. I am under the weather today and shouldn't have posted at all. I don't have much experience with post war side by sides and you could be absolutely right about curved barrels being an indication of a problem - just outside my experience.

Please excuse me.

Thanks!

Mike

Mike. I'm sorry to hear you are under the weather. I hope by the time you read this, you'll be feeling better.

I think its still apples to oranges. Reread my original post about the Rota. Its bores were oriented to shoot away from each other on the vertical plane--one up and one down. It is also a new gun. Shooting it will only prove what my eye has already told me and will negate the ability to return it as new to Cabela's which I've done. Incidentally, they refunded my purchase price and all my related expenses too. One look down those bores was enough proof for them I'm sure.

Best made Purdey and many other British hand built doubles have been made in the "traditional" way with chopper lumps for decades. Also, most are the traditional light weight 12 bore. The larger bore will offset bore flaws no small bore gun will tolerate and also needs its barrels to bend slightly out at the breech end to reduce as much weight as possible while allowing for the bigger chambers. However, most of the traditional 12 bore doubles I've seen had relatively straight bores from at least 3/4s their length on to the muzzle.

However, all tradition based prejudice to the contrary, some of today's production 12 gauge doubles with straight, well aligned bores built on a demi-block will shoot rings around these finely crafted, but antiquated, guns. If this was not true, we'd see Purdey doubles being used for serious clay target games today. In fact, some of today's better small bore doubles will shoot just as efficiently as a 12 ga traditional double. However, that takes straight, well rounded bores to do so. Make no mistake.

Are you dead certain that the Repro Parkers were originally made with choke tubes? I've never seen a new one with tubes. I thought they all had fixed chokes or am I misreading you.

As far as slightly bent barrels on AyA guns, you are correct. My Matador shows this. It is a 16 with chopper lump barrels and was made in 1960. However, the bends end less than 1/4 way down the bores and the curved breech sections are aligned exactly on the same horizontal plane, back to back as you describe. the bores are perfectly matched on the horizontal plane and shoot to exactly the same point at 40 yards without any curve at the muzzle end other than the choke taper. This gun has very cleanly .killed a fair number of pheasant with both 7/8 and 1 ounce loads out to past 37 yards. It shoots very efficient patterns. Aya guns are noted for their excellent barrels, even on their least expensive models. This is not true on many of the other lesser expensive Spanish doubles I've examined. Even some of the supposedly better ones have shown bore problems they should not have had. As I said, high price is no gaurantee.

The AyA shows no vertical disparity at the muzzles like I saw in the Rota 28 ga.double. The last 3/4s or more of the barrels on the Aya are dead straight, very round, and toed in along their straight bore lines. It shoots very well.

All the Parker repros I've examined do show a tiny bit of curve very similar to the AyA, but the 28 ga guns show almost none. The barrels are also dead straight from at least 3/4s back from the muzzles forward and tapered to fit nicely together at the muzzle. Small bores in general also seem to exhibit or need a bit less toe than 12 and 16 barrels. Less recoil would dictate this I suspect. 410 bores show the least toe of all it appears, especially if the action they are built on is proportional and not a 12 or 20 sized block.

The Rota 28 ga. barrels were curved all the way down to the muzzles, the right barrel much more than the left. If you'd seen it, you'd know what I know and probably would reject it too.

Finally, Briley and other gun barrel specialists will rebore tubes at an angle into existing barrels or insert eccentric tubes, but its only to correct an existing alignment problem. Briley will also tell you that their corrective measues will fix the problem only to a certain degree. Some doubles with out of whack bores can't be corrected enough to shoot effectively. Briley will also tell you that these methods will effect pattern efficiency negaitively to some degree and work best in 12 bores. Longer thin walled tubes also help keep the patterns effective but can't always be used.

A small bore double shoots best if it has nice straight, well rounded bores fromat least just in front of the chambers to the muzzle in my opinion and experience. I'll settle for nothing less in any one I purchase. Anyone else is entitled to spend his money his way, but I'd still advise anyone to go for the straightest, best aligned bores they can find. Good luck.

PS: for those of you folks reading this thread, be sure not to confuse the outside tapered contour found on most double guns for the bore straightness I'm referring to. Nearly all double gun barrels are turned to a curved taper from in front of the breech to the muzzle. The very slight, matched bends Mike and I are discribing on some SxS and fewer O/U guns allow for the necessarily thicker breech ends to fit together closely enough to match the action fences and not make the whole action block too wide nor the gun unwieldy. However, from about 3 inches or so forward, the barrel walls can safely be tapered due to the normal pressure drop. This curved outside taper helps reduce the weight of the barrel pairs for better handling and balance. Some SxS barrels bend outward very slightly at the breech end and also have flats ground on the inside of their chamber ends where they abutt each other to further reduce width and related weight, This is true with nearly all chopper lump barrels.

Barrels inserted into a mono or demi block can often be bored and fitted without any bend from breech to muzzle, especially small bore doubles. Most O/U guns and many doubles are done this way. My Berette 409 16 has a demi block and much straighter bores end to end unlike the AyA.

The Rota 28 barrels were also built into a demi block and therefore, should have needed little to no bend. The gun's barrels were just plain not properly straightened prior to assembly and just plain poorly made with crooked, mismatched bores. However, the gun is probably for sale again at Cabela's in Dundee. Its up to any who will take the chance. I sure don't want it, not at any price.

Joined: 03 Jul 2005 Posts: 370 Location: Amarillo, Texas

Hi 16GG:

Thanks - and I am feeling better.

What I meant was that a post quoted Oscar Gaddy as saying that on Parker Reproductions the choke axis were cut at an angle to the axis of the bore to regulate the barrels to shoot straight. I don't doubt the Parker Reproduction tubes are straight. Briley can correct POA/POI problems by cutting a screw-in choke eccentrically that would act the same as a choke axis cut in crooked to the bore axis. I didn't mean that the Parker Reproductions had choke tubes.

If you have two perfectly straight bores at an angle to each other the only way they won't shoot crosseyed is if you cut a choke axis at an angle to the bore axis. I think it is a better solution to curve the barrels.

All of the over and unders I know of have essentially parallel bores. Perhaps that is one of the reasons they are overwhelming preferred by the all the competition clays shooters - perhaps they can be made to pattern better because they have no bend. I have no doubt that the Krieghoff OU or Kolar OU barrels pattern much better than the modern Purdey side by side or any other side by side. On the other hand I love hunting quail with my Gallyon 16 gauge or my Parker 16 gauge or my Kunze 16 gauge - all SxSs. I couldn't imagine hunting quail with the Krieghoff OU. If I took the Krieghoof Essencia (I wish I had one) it would have either bent barrels or it would have chokes cut in crooked to the axis of the barrels because the breech centers are farther apart than the muzzle centers - I bet Krieghoff curved the barrels. I believe most quality SxS have curved barrels with the choke axis in line with the last half of the muzzle end of the bore axis. Now the most efficient pattern would come from the Kolar OU - but the most efficient people are in the drive-up lane at Popeyes waiting for their extra-spicey.

I would hate to think that someone passed up buying a perfectly lovely perfectly regulated 16 gauge SxS because it had curved barrels. They are supposed to be curved in many many many cases.

If you buy a modern side by side from Krieghoff it either has bent barrels or the chokes are "crooked". If you buy any side by side you either have curved barrels or "crooked" chokes or your gun shoots screwy.

Thanks for continuing to be friendly to me - I really do appreciate it and have enjoyed the discussion today.

Thanks again!
Mike