So what gives with the 36 ga nomenclature for the .410 bore? Is there some secret to gun makers that we have yet to uncover, or just an easier way to keep continuity i.e. 12 16 20 24 28 32 36?

in fact, the .410 bore is equivalent to a 67 gauge


https://www.americanrifleman.org/articles/2017/12/6/rifleman-q-a-is-410-a-gauge/



In 1961, the “Permanent International Commission for the Proof of Small Arms” (generally known as “C.I.P.”) finally settled on a designation and standardized measurements for the .410, reversing its earlier decision to use the inaccurate description of “36 gauge” (it would actually be a 67½ gauge).

It was not to last. The dithering by the Commission, for over 70 years, as to what the official name for the gauge should be had lead to the long-term adoption of the terms “36 gauge” for the 2" & 2½” shells and “36 gauge magnum” for 3" shells in mainland Europe and these were too well established in the minds of users to be changed arbitrarily. In 1969, the name “36 gauge” was appended to the official name in parentheses and thus it has remained.

http://www.smallboreshotguns.com/410-bore/

It's all a mixed up deal. British proof houses accept .405" to .415 as the range of bore sizes for a .410. It takes 67 balls of .410 diameter to be a pound. Thus, it is truly a 67 gauge.

There actually is a 36 gauge, at .506" bore diameter, and Eley loaded shells for it. There's a picture of a box of them in Gabriel's .410 book. There was also an even smaller than .410" chambering ......... a .360" cartridge of 1 3/4" length and carrying 3/16 oz. of shot.

So, how the .410 ever got the mistaken identity of 36 gauge in the first place is a mystery to me. Same reason a largemouth bass is still called a "trout" in parts of the Deep South, I guess.

SRH

Just go metric and call it 12 mm --

Calling it a 12mm would also be inaccurate as a 12mm is actually .472.
Being one who carries a 10mm handgun everyday I knew that 12mm was much larger than .410 as a 10mm is 40cal.
The outer diameter of those shells may have been 12mm.

12 mm = .47244" . This, of course, is not the bore size of a .410 shotgun but would fall within the chamber dimensions.
As stated 36 gauge = .506", obviously not a .410.
a .410" bore size per both British & German proof charts = 67.49 gauge.

Some gauge charts only go down to 50 (.453") but there are others, more complete, which continue @ .45" & go down to .30" in .010" increments. these are;
.45" = 51.04 Ga
.44" = 54.6 Ga
.43" = 58.5 Ga
.42" = 62.78 Ga
.41" = 67.49 Ga
.40" = 72.68 Ga
.39" = 78.41 Ga
.38" = 84.77 Ga
.37" = 91.83 Ga
.36" = 99.7 Gauge
.35" = 108.49 Ga
.34" = 118.35 Ga
.33" = 129.47 Ga
.32" = 141.95 Ga
.31" = 156.14 Ga
.30" = 172.28 Ga

This could be extended further as;
7 mm = .276" = 221.24 Ga
6.5mm = .256" = 277.25 Ga
6mm = .236" = 353.88 Ga
5.6mm - .220" = 436.84 Ga.

You can take 16 & divide by any gauge no & it will give the weight of the round ball in ounces or divide by 7000 & it will give the weight in grains.
Probably more than anyone wanted to know, but that's the scoop.

Regardless of how widely used or how much accepted either 12mm or 36 gauge are total MISNOMERS, for a gun with a .410" bore. either smooth or rifled. In metric its a 10.41. Remember the old 10.4mm Swiss Vetterli rimfire (.41 cal) while in gauge it is as stated a 67.49.

I could be wrong but my personal belief is the original promoters of it just didn't want people to truly realize just how LITTLE the thing actually was. 36 gauge sounded bigger than a 67.49 & 12mm sounded bigger than a 10.4mm.

Awesome! Thank you guys!

Don't conflate the nominal gauge of the chamber with the bore diameter (in gauge measurement). The most common 12 ga, as we see from German proof marks, often have 13 ga. or 13/1 ga. barrels. The actual bore diameter in both smooth bore and rifles, very often don't match the nominal chamber.
Mike

Very True Mike, & a good point. The chart I posted was from the proof houses & indicates the "Correct" size of a bore, based on a pure lead, perfectly spherical ball that will exactly fit. It certainly was not meant to imply that every 12 gauge, for instance, that has ever been built left the factory with exactly a .729" bore diameter.

For many years the proof housed measured the bores with a series of plug gages. The barrel was marked according to the largest gage which would enter the bore to the prescribed depth. This then denoted a "Range" for the size & not an exact dimension. 13 = .710" diameter thus a 13/1 = .719. A barrel marked 13/1 at proof thus meant it would accept the .719" plug but would not accept the .729" one. It could have been anywhere in between.

The point is though all of these other sizes were named for their "Nominal" bore size from which their chamber sizes were developed. The bore sizes themselves hark back to muzzleloader times. When breech loaders were developed the guns were no re-named for their chamber size but kept their name according to their nominal bore size. "IF" they had been renamed according to their chamber the 12 gauge would have become approximately a 9 gauge (.8025") which would have fallen about mid chamber.

As stated earlier 12 mm falls within the chamber diameter of the .410. 36 gauge (.506") is even well beyond that, Neither is an indicator of the actual size of the .410's (67.49 gauge) bore.

Fourteen years ago I owned both a .410 SXS with no chokes and a true 36 gauge percussion SXS with no chokes. I did a write up for the fourteen website which included a photo of the two guns muzzles displayed side by side. Below is the link to my write-up.

http://www.fourten.org.uk/36g410.html

Steve

Here is something to throw into the evolutionary trail from the 1908 Sear, Roebuck & Co. catalog --



One of the links above said the .410-bore was being loaded in America by 1910. The book, Encyclopedia of the 410 Shotshell in American 1914 - 1942, says Remington-UMC introduced factory loaded .410-bore shells in 1914. There is no mention of such shells in the 1913-14 Remington Arms-Union Metallic Cartridge Co. catalog, but they do appear in the 1915-16 Remington Arms-Union Metallic Cartridge Co. catalog --



Winchester produced their first box in July 1915. Western Cartridge Co. began production in 1916. Peters joined the fray on July 1, 1917, becoming the fourth producer of .410-bore shotshells in North America.

The last big J. Stevens Arms & Tool Co. catalog, General Catalog No. 54, circa 1914, shows this gun and says "The Gun That Introduced .410 Loaded Shells" --

R-Man;
Do you know when the .410 was introduced in England or on the Continent?
I have a copy of that 1908 Sears catalog & had noted the little "Ladies Gun" before.
Incidentally, "Equal Volume" for a ½ oz load of shot would be around 35 grains of Black so that 40 grains in the .40-85 case would be a pretty p[otent load. Not overly so, but certainly no pip-squeak.

I could read what is in Ron Gabriel's book, but I have no period British paper to confirm/refute/add to the mix.


One other interesting U.S. item from H & R Catalogue No. 12, Copyright 1913 --

Miller, if I may offer what I have found in my readings and search for more depth concerning the .410 ............

I appears that the year was about 1882, in England. There exists a box of .410 shells that are believed to have been manufactured just after 1880. There are advertisements in 1882 issues of Shooting Times and The Field for the .410. Eley advertised a 2" Gastight loading in 1885. Sounds like that narrows it down to the very early 1880s.

As far as the "Continent" goes, there is mention of the .410 as early as 1886 in French cataloging. It is actually for a 12mm cartridge. Ronald Gabriel contends that, even though the 12mm cartridge is slightly larger than the .410, most consider it the European equivalent of the American and British .410.

There is much more info about the .410 in Gabriel's excellent book, IYI. And, Researcher may have more ........... I hope!

SRH

Those old H&R shotgun ads that Researcher provided mention a clambering for a .45-70 shot cartridge. I've heard of people who attempted to make shot loads using .45-70 brass for short range loads in various rifles, but never heard of a dedicated shotgun chambered for .45-70. Was this a handloading proposition, or did one of the major ammo manufacturers actually produce .45-70 shotshells? Seems like an idea that might have actually gotten traction, except for the potential problems of someone firing rifle loads in a choked shotgun bore.

Keith;
That mention of the .45-70 shot cartridge is under "Ammunition" not under the gun list. At this point in time, there were many old "Trapdoor" Springfields out there which had been declared surplus by our Government, many of them sold through Bannerman's. My take here is they were simply listing shot loaded ammunition for these guns.

Incidentally, the first shotgun I ever shot was a little Small Frame H&R 28 gauge single hammer gun. It looked very much like this 1905 model but do not recall now if it was an ejector or non-ejector. I was never able to acquire it but did get to shoot it again later in life & also weighed it at that point. 4 lbs 2 oz. I believe it was either 26" or 28 " barreled.

Thanks, Researcher & Stan. I was pretty sure the .410 did not originate in the US but was not sure just how far back it went.

Researcher, sorry I got mixed up there in the previous post & gave you the wrong handle. You & the R-Man are both extremely knowledgable & I value input from either, just sometimes forget for sure which one has posted when I reply.

PS, meant to add the .45-70 case is of course too large to chamber in a .410. The ad from the Sears catalog Researcher posted did list the .40-85 Win round being used as a chambering for their little "Ladies Gun". A present-day .444 Marlin case will fit most .410 chambers, there may be some rim interference with some. This case is short so a ½ oz load is about all it will hold.

In the 1913-1914 Remington Arms-Union Metallic Cartridge Co. catalogue they have five pages of rifle caliber shot cartridges --











By the 1923 Remington Arms Co., Inc. catalogue it is down to two pages but the 45-70 is still offered.

im still looking for a nice 24 and 32ga o&u....that works, and isn't ancient. no one has the newer ones.

There's a good reason ...........

SRH

American arms made them a while back...but I missed them.

They are nice and were made by Fausti ?
We have them and reload for them
American Arms Silver II
The Silver 1 has extractors
The Silver II has ejectors

Mike

A year or two ago I almost bought a set of 24 ga. barrels made for the Beretta 686 series. According to the shop that was selling them they were made by Beretta to fit the 20 ga. action. Probably more common in Europe than on this side of the pond.
Here's a 24 ga. 686. It's been sold:
https://www.gunsamerica.com/998139103/60...-shells-NIB.htm

you say you have them....?

I remember the fausti importer was in ca. I talked with the importer and was planning a few 9mm o&u's for the collection, but lost touch with him and well.......rest was history.

Yes, full set 410, 32, 28, 24, 20, 16, 12, and 10 gauge Fausti over/under guns (American Arms imported them)

What FUN,What fun

Only issue is the 24 and 32 guns have 70mm chambers and we can only find 65mm hulls. So we just load them in MEC 600JR loaders that I converted to 32 and to 24 gauge.

Or we use these
https://www.gunbroker.com/item/795716424
https://www.gunbroker.com/item/795241788

Mike

didn't that importer have connections to the right ammo in Italy?

does fausti still make its 9mm o&u?
I sold my bernadelli semi auto 9mm years ago. kept jamming and all the gunsmiths told me to get rid of it. I did. it was a lemon.

whats your experience with fausti patterns and chokes with the smaller gauges? he told me full full was suggested.

this was something i was going to get. the american arms s2 - 2 bbl set.
24/32ga.....

Patterns?? These shotgun kill dove and do right well at skeet

I did fit a set of 32 gauge barrels to a 28 gauge gun, not too much fitting work on the barrels, left the action alone. The barrels at one time were available from Gunparts.com

Mike