A question I have had several times in the past and never asked: Why are barrel lengths in the US primarily in the 26,28, 30 inch range while many barrels of English made guns are in numbers like 27 or 29? Are our US stated even numbers a conversion from a metric measurement in Europe? I know this is probably a ridiculous sounding question to many of you, but it just hit me this morning when I saw a set of 27 inch barrels on a Lang and I thought I would get an answer once and for all. Thanks.

Perry: I think 27 inches is very close to a common metric dimension. I know that when I was in Spain and ordered a custom s x s that it came with approx. 27" barrels. And I suspect +/-29" would be another. And when they are up for sale on this side of the pond, the seller may use that dimension in inches (either 27 or 29). just speculation. Gil

Truth is British gunmakers would give the customer whatever he was willing to pay for. It is a metric issue, or conversion by and large. A lot of Spanish guns are 27” which is 68.58mm. 70mm would be 27.56” so 27” is a slight compromise. 29” is 73.66. Some English makers used 29” to differentiate their guns being slightly lighter. 25” was the brainchild of WWGreener which is 63.5mm. The metric to inches is a bit messy. You see a lot of 27 & 29” Spanish guns which were common factory legends unlike American guns which would almost always have been cut down to be those legends. German and Italian guns are commonly seen in 27&29”as well.

There was a time not too long ago which the prevailing wisdom was 30” is too long for a fast handling double and 25-26” was where the market was. Now guns with 30” seem more sellable and those with 32” are even in more demand. 25-26” are very hard to sell. I like double more for handling, feel if you want, than any flat statistics.

Ky, did you mean 25" was the brainchild of Churchill ? I was not aware of the Greener in this development.

As to 29" a lot of Dicksons were made in this length. I have a Purdey with original 27" barrels.

Yes Daryl, senior moment. Got distracted by autocorrect and retyped the wrong name. Churchill was the driving force. But I’ve seen a lot of other makers who built 25” guns for their customers. I owned a Greener 25” for a bit. Long gone sad to say.

Up to the late 1890’s 30 inches was generally considered the standard length for the barrels on 12-bore game gun, although I am sure there are plenty of exceptions.

This was viewed as being the length required to achieve a complete burn from a black powder 12 bore cartridge, thus reducing the smoke and flash as well as moving it a bit further from your face.

With the adoption of smokeless powders less length was needed for combustion, and 28 inches became regarded as the standard with XXV (Churchill), 26, 27 and 29 inch being variously offered for promotional reasons.

There is Churchill XXV 12 bore 3” Wildfowler in Holts next sale.

The present trend to longer barrels seems to be due to the feeling that they are more effective on high driven pheasants.

True all London gunmakers had customers they catered to. If they wanted 27 they would be more than happy to. There was a time when gunmakers would make up a few guns and they did so in the 29 length. It was called "The London Length". That way if a customer came into the shop and wanted a 28" gun or one came in and wanted a 30" gun the salesman there in the shop could most likely talk them into the 29" gun.
As far as gunmakers catering to their clients, I once read an article that Donald Dallas wrote that a client went into Boss & Co. and asked for a self opener. In 1909 Boss did not make that gun. So down the street to Purdey they went and bought an action. They took it back and engraved it in the Boss pattern. Hence a Boss that was actually a Purdey.

If you convert the other way, I think it is more obvious. The pretty standard barrel lengths in Europe for both shotguns and rifles were and are 600, 650, 700 and 750 (mm). Converted to inches these are all within a tenth or so of 23.5, 25.5, 27.5 and 29.5 inches. I presume rough barrels were sold back and forth between all the suppliers and the English finished them at the odd numbers so either British or European lengths would be long enough to finish out.

The UK govt. adopted the metric system in 1965 and, as in Canada, many of the citizens still think of length in imperial. If your odd-inch-length British barrels are pre-1965, then I wouldn't think metric conversion has anything to do with it.

My Husqvarna 310s are 70 cm and 72 cm which equates to 27 9/16-inch and 28 3/8-inch on my Lufkin dual measure tape.

Poor Jimmy just gave up when the yahoos in this country just couldn't comprehend the metric system!!

These inches to metric conversions need to either have the decimal point moved, or change millimeters to centimeters. But as JBLondon correctly notes, English gunmakers were still measuring barrels in inches prior to 1965, when the Metric System was adopted. So the commonly seen barrel lengths of 27" or 29" have absolutely nothing to do with the Metric System, and are most likely a matter of marketing and/or inventory control. It would be interesting to know if there was some other logic behind the adoption of those uneven barrel lengths. Perhaps we will soon be informed in the Perpetual Never-ending Epic OCD Reilly Thread that it was yet another invention by E.M. Reilly and his imaginary 300 employees.

In addition, most U.S. makers were using the even numbered lengths of 26, 28, 30, and 32 inches ( or more) long before most of the world adopted the Metric System. But we see some guns that vary from those common even number barrel lengths. Robert Elliot stated that the Syracuse Lefever guns were sold only in lengths of 28", 30", 32", and rarely in 26" lengths, and that uneven lengths are a good indication of cut barrels. But I have seen many Lefevers with odd lengths of something like 28 1/8" or 30 3/16" that are very obviously uncut due to the presence of full length choke tapers and intact keels between the barrels and ribs. This practice of leaving the finished barrels a bit long is most often seen in the older rod cockers or two-hook cocking system guns, and some small hook guns. However, I have never seen uncut Lefever barrels that are some fraction of an inch under some even number. It seems like they were OK with giving the buyer a bit more for his money, but never less.

The effect of barrel weight and length is now quantifiable in terms of pounds/ounces or grams/ kilograms and moment of inertia. Note that the muzzle area of the barrels are more or less twice as far from the balance point as the butt area. Balance moves as a function weight change times length from balance point to the removed/added weight. Inertia, however, changes as a function of weight added/removed and the length form balance point squared (length times length). That is weight removed/added from butt area will have 1 weight times one length. On the other hand, one weight times two length times two length (1 W times 2 L times 2L = W times 4L) shows that a barrel weight change(such as shortening or lengthening barrels) will affect inertia by four times as much as the same weight change at the butt. So, changing the barrel length by 2" (say about 4 ounces) would have about the same effect as changing the weight at butt by 16 ounces.

From the above we can see that barrel length is a very useful tool for adjusting gun handling.

DDA

I love it when Rocketman makes me revisit my high school algebra and college physics! However, I don’t think I would have understood the importance of that explanation if he had not summarized with “ So, changing the barrel length by 2" (say about 4 ounces) would have about the same effect as changing the weight at butt by 16 ounces.” Noodle on that you all and realize that barrel inches really do make a BIG difference in how a gun handles.

That said, as I have had Don tell me again and again, there is no right or wrong with this stuff ( gun feel, dynamics or handling). One man’s preference is another man’s anathema!

Don, I hope you are well my friend! We miss you down here in the Carolinas.
Dr. P

It would if they were sourcing rough or semifinished barrels from Belgium or France, which the bulk of the cottage makers and finishers probably were They likely may have bought stock length european barrels and trimmed them to shorter even inch lengths.

Salutations, Dr. P., always good to hear from the N.C. crowd. Thank you for your kind words. Shot a round of skeet with a group of Univ. of Mo. Science and Technology students a couple of weeks ago. It was a real hoot watching the "light bulbs" come on over their heads as we spoke about handling in terms of weight, balance (center of gravity), MOI at CG, and at butt (parallel axis theorem). It was a real world application of knowledge they had learned but had never considered as applied to guns. Great fun for an old man!!!

Mostly well here, but do have parts starting to wear out - having a shoulder replaced in a couple of weeks.

Really looking forward to getting back for a Southern SXS when covid goes away. Hope every one there is safe and well.

DDA