Not long ago I did an article on British shotguns in which I mentioned that the chambers on my own 16-gauge had been lengthened from their original 2-1/2 inches to the American 2-3/4 inches. I also said that potential buyers shouldn't be deterred by short chambers in a British double, because one option was indeed to lengthen them--as had been done to mine.
The article generated a few angry letters. Some of my correspondents went so far as to say that you should never lengthen chambers on a shotgun, and that I was guilty of handing out dangerous advice.
Having always considered myself a conscientious person when it comes to guns and their use, and being the owner of several old doubles myself, I decided to research the issue of chamber length. In the process of that research, I learned a few things that may be of interest to those who either own or who are contemplating the purchase of an older shotgun.
Many Americans may not realize it, but short-chambered guns are relatively common in this country. British guns, in fact, comprise only a small percentage of those guns still in use that have, or originally had, chambers shorter than our current standard of 2-3/4 inches. In fact, there are quite a few hunters and shooters out there who are totally unaware that they are firing U.S. standard-length shells in guns with short chambers.
That situation came about because the American firearms and ammunition industry didn't settle on 2-3/4 inches as a standard for all gauges (except the .410, where the standard became three inches) until well after they had converted from the old blackpowder guns and loads to modern smokeless powder. For at least the first quarter of this century, standard chamber lengths were: 12-gauge, 2-5/8 inches; 16-gauge, 2-9/16 inches; and 20-gauge, 2-1/2 inches.
American gun manufacturers gradually changed over to what had indeed become, by the beginning of World War II, an industry standard of 2-3/4 inches. They did not, however, do it at once, nor did they do it at the same time for all gauges. Ithaca standardized its 12s, 16s, and 20s at 2-3/4 inches in 1924. But other companies didn't follow that pattern. The legendary 16-gauge Parker Invincible made for A.C. Middleton in 1929 had 2-9/16 inch chambers. As late as 1936, L.C. Smith was still making 2-9/16 inch chambers in 16-gauges, even though it had settled on 2-3/4 inch for its 12s and 20s.
The problem with most older American guns, except 12-gauge waterfowl guns bored for the longer three-inch shells, is that they are not marked to indicate chamber length. If you're shooting a pre-World War II American gun and you have any doubts, have a gunsmith measure your chambers. Don't be surprised if they are shorter than 2-3/4 inches.
It's impossible to tell just how many of these old, short-chambered (or formerly short-chambered) guns are still around. But you'd better believe they're fairly common. Ithaca made only about 45,000 NIDs as compared to more than 200,000 Flues doubles. Most of the latter, many of which are still being shot today, had short chambers.
I must add also that my research focused only on doubles. By the time you throw in the mass-produced repeaters that began to appear in the early 20th century, you start to see the scope of the problem.
For the most part, European doubles not made for export to America had 2-1/2 inch chambers until World War II. Unlike American guns, however, most European guns have been stamped with chamber lengths for some time. This measurement will typically be in millimeters (mm).
I have a pre-war German Sauer stamped "16/65mm" (the gauge followed by the chamber length). That practice pretty much continues to the present. My two modern Spanish guns are marked "28-70" and "20-70"--again, the gauge followed by chamber length.
However, I've owned three French guns--one by Manufrance, the country's largest firearms manufacturer; one by Verney-Carron, a smaller but highly reputable maker; and one that bore no maker's name. None of the three carried chamber length markings. All were pre-World War II 16s, and all had 2-1/2 inch chambers.
Currently, manufactured European guns, like their American counterparts, have adopted the 2-3/4 inch standard--70mm being the metric equivalent.
So how about all those old guns, both foreign and domestic, with short chambers? Many are in excellent condition. Should they be relegated to the role of wall hangers?
My answer to that question, having owned and used a number of these guns for several years, is a resounding no! But their use does require a bit of common sense.
Although some aspects of the short-chamber issue are open to debate, one is not. You shouldn't shoot 2-3/4 inch shells in guns with chambers shorter than that, the same way you shouldn't shot 3-inch shells in 2-3/4 inch guns.
The result is not likely to be catastrophic in the sense of a gun blowing up in your face. On the other hand, it's not going to do good things to the gun or the shooter. The problem is that a 2-3/4 inch shell, which typically measures around 2-5/16 inches before it has been fired, will fit very nicely into a chamber as short as 2-1/2 inches. But when you fire the gun, the crimp may not have room to open fully. Even if it does, the result will be pressures much higher than the gun was designed to handle. That, in turn, could eventually cause the gun to "shoot loose." You're likely to feel another result quite directly in the form of excessive recoil on your cheek and shoulder.
Remember what I said earlier about people shooting modern shells in short-chambered guns without knowing it? Ever hear anyone tell about how Grandpa's old double is a "real hard shooter"? Whenever I hear that, I'm more than a bit suspicious that Grandpa's gun may have short chambers. Add to that the odd stock dimensions of some old guns and you have a sure-fire recipe for a "hard shooter."
But coming out the business end, that hard shooter isn't likely to be very effective as a game getter. Even if it were a good idea to shoot 2-3/4 inch shells from short chambers, the excessive pressure would be as bad for the pattern as it is for the gun and for your bridgework.
One relatively simple remedy, especially for grouse hunting, and especially with the 12-gauge, is to shoot 2-1/2 inch shells. There are several sources for the short 12-bore loads. I'm more familiar with the smaller range of choices available for the 16, having used Fiocchi's nickel-plated 8s, as well as Lyalvale's 9s and nickel 7-1/2s. Although they both sell short 20-bore loads as well, the shell I favor for that gauge is marketed by Orvis as the "English Light Load." The 2-1/2 inch Orvis shells, carrying 7/8 ounce of 8s, produce beautiful patterns with extremely mild recoil.
Using short shells, then, is a perfectly acceptable solution--if the gun will be used exclusively to hunt grouse and woodcock. But if you intend to shoot more than a few rounds of sporting clays or skeet, the price of 2-1/2 inch shells quickly becomes prohibitive. And if you want to use the gun on larger game, such as pheasants, you'll want more shot than the 7/8 ounce you can get in a short 20-gauge load, and perhaps even more than the ounce a 2-1/2 inch in 16 will hold.
If you reload, you can deal with the target-shooting situation, working either with factory 2-1/2 inch hulls, or trimming down 2-3/4 inch cases. You also have to do a bit of tinkering with wads.
But if you want a heavier shot charge, you have no choice but to go to the longer shell. This means lengthening the chamber, which some people apparently believe is like violating all Ten Commandments.
True, there are some guns in which chambers should not be lengthened. Assuming, however, a gun is in otherwise good condition, I believe it is more a question of affecting the gun's value than it is damaging the weapon or the shooter. If your gun is worth several thousands dollars as a collectible, part of that value comes from the fact it is in original condition, which means you don't want to tamper with the chambers.
For example, if I owned a Purdy, a high-grade Parker, or the like, I'd leave the gun alone. (Interestingly enough, though, George Bird Evans lengthened the chambers of his famed Purdey from 2-5/8 inches to 2-3/4 inches.)
But should that advice apply to guns that have value mainly for their handling and shooting qualities rather than for their collectibility--guns like the Parker Trojan, Fox Sterlingworth, or my Scottish-made Alexander Martin? The answer to that question is far from unanimous. For example, Michael McIntosh in his fine book on American doubles, Best Guns, sees no reason not to lengthen the chambers if the gun is intended to be a "shooter." Larry Del Grego regularly lengthens short Parker chambers to 2-3/4 inches when he does restoration.
English guns, often with thinner barrel walls, are more of a problem. Mark Cromwell of New England Customer Gun Service will lengthen chambers on English guns if there is sufficient wall thickness. He will not, however, lengthen a 2-3/4 inch gun to three inches. Kirk Merington, an English gunsmith, agrees with Cromwell on both points. He goes on to stress the importance of having the gun examined by a competent gunsmith before you shoot it with any loads. If the gun is in good condition, Merington in fact advises lengthening chambers to 2-3/4 inches--because of the difficulty in getting 2-1/2 inch shells in this country--unless he is sure his customer will shoot only short shells in the gun.
Those who advise against lengthening 2-1/2 inch chambers to 2-3/4 inches include the distinguished firm of James Purdey & Sons, Ltd. They, and others who agree with them, point out--quite correctly--that 2-3/4 inch loads, especially American factory shells, are likely to generate more pressure than 2-1/2 inch loads, especially American factory shells. Lengthening the chambers, they continue--again correctly--does nothing to adapt the gun to these higher pressures. In other words, while it may be better than shooting long shells in short chambers, it's still a bad idea.
Some of the critics will point to rechambered guns that rattle worse than an ox cart and tell you they have "shot loose." Maybe. But I doubt it. In the case of the old doubles, that condition is much more likely the result of someone who consistently closed his gun like John Wayne in the movies on his way to clean up the local saloon. Take the best break-open gun ever made, slam it shut a few thousand times, and you can make it "shoot loose" without ever popping a cap.
Those who criticize lengthened chambers also neglect to mention that no competent gunsmith is going to stop at simply punching out an extra 1/4 inches of steel. He is also going to lengthen the forcing cone. On many old guns, forcing cones tend to be short and very sharply angled. Modern guns have longer, more gently tapered cones--reducing both pressure and felt recoil. If you have the chambers and the cones done together, as you should, you will not end up with a significant increase in chamber pressure by going to 2-3/4 inch shells--if you use your head.
For example, if you're modifying a 12-bore so you can bust clays as well as grouse, you can either reload standard 2-3/4 inch shells using one of the many available formulas that will keep pressure down around 9,000 LUP, or you can purchase new factory ammo, such as Winchester's AA Super-Lites, which will reduce pressure and recoil all the more. Even for hunting, you can work up 1-1/4 ounce loads that will give you a velocity of more than 1,200 feet per second--packing plenty of punch even for pheasants--and still keep your pressure under 9,000 LUP. You can do the same with 1-1/8 ounce hunting loads for the 16-gauge, and one-ounce loads for the 20.
What you shouldn't do with a rechambered gun is feed it a steady diet of the heaviest factory loads you can buy. Although all American factory shells are not equal, heavy hunting loads tend to push up toward the high end of the industry standard for pressure--and that is definitely more pressure than your old gun was designed to take. Also, if you're carrying a light, small-bore gun--say a rechambered 20 that scales well under six pounds--it's likely to slap you around if you stuff it with short magnums.
Should you punch out the chambers of Grandpa's old grouse getter? If it's an American or European gun in good shape, in all likelihood there would be no problem. If it's an English gun, you need to exercise a bit more caution. But in either case you should seek the advice of, and have the work done by, a competent gunsmith. And under no circumstances, no matter how many times you've already done it through ignorance, should you ever shoot 2-3/4 inch shells in a short-chambered gun.
Copyright (c) 1996 Larry Brown. All rights reserved.
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