Calibre confusion

Will the real 38 please stand up

Rod Pascoe

Since the invention of self-contained metallic ammunition in the 1800s, there have been thousands of cartridges developed all over the world for police, military, commercial and sporting purposes.  Of course not all of these cartridges, and the guns they go into, have survived the test of time and many have fallen out of favour for one reason or another.

It seems the demise of this older ammunition is more than made up for by the introduction of new varieties, usually starting life as a wildcat in someone’s shed, and some of these wildcats became commercial propositions as firearm and ammunition manufacturers saw marketing potential in the new offering.

What do the numbers mean?

These days it’s normal to hear shooters refer to a number, such as 308 or 22, and most will know what they mean. In this case it’s more than likely they’re referring to .308 Winchester and .22 Long Rifle but of course there are other 308s and 22s apart from these two examples. You could say this is where calibre confusion began and the numbers by themselves don’t mean much.

Back in the mid-1800s every man and his dog was manufacturing guns, due to huge technological advances made in moving from muzzleloading firearms to those using the new self-contained metallic cartridge loaded into the breech end of the firearm. In the US names like Maynard, Sharps, Colt, Ballard, Peabody, Wesson, Remington, Stevens, Winchester, Bullard and Marlin were all moving into this emerging and lucrative business thanks mainly to the Civil War, buffalo hunting, the opening up of the American West and Indian conflicts. Often the firearm maker’s name is used in the cartridge description - .45 Colt for example - or it could be a place name as in 6.5mm Creedmoor, a country (.303 British), something abstract (.38 Super) or even more obscure (5.5mm Velo-Dog).

In black powder days in the US, a common way of describing a cartridge was to use the bullet calibre or its diameter, for example .45 followed by the amount of black powder used, say 70 grains, hence: .45-70. Sometimes bullet weight would also be added and, to make sure there was absolutely no confusion, a name attached ‑ .45-70-405 Government for example. Other early US makers would often add the cartridge case length as in 44-100 2⅝” Sharps or .44-90-2.6” Remington.

A major confusion in this era was that a .40-70 cartridge made by Frank Wesson for example would have a bullet diameter of .392” whereas the .40-70 made by Remington has a .403” bullet and the .40-70 by Maynard for the 1873 Model has a bullet diameter of .425”. Big differences but all categorised as .40 calibre cartridges - and none of them were interchangeable.

Every manufacturer of the time was doing their own thing and not comparing notes with competing gunmakers, making both the guns and ammunition to fit them. No one saw any reason to standardise calibres or cartridges although, as you can see from the .40-70 examples, you had to be careful you were buying the right brand of ammunition for your type of rifle. It’s different now as not too many rifle manufacturers have their own special or unique ammunition - I say not too many but Winchester, for example, went back to the days of exclusive ammunition with their WSM and WSSM experiment.

Where are we now?

Despite the large number of cartridges in use today there’s only a dozen or so standard diameter rifle projectiles produced, even fewer for handguns, which greatly assists barrel and bullet manufacturers in their production process, with organisations such as the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI) in the US and Commission Internationale Permanente (CIP) in Europe to regulate the technical aspects of ammunition, firearm, ammunition manufacturers and component makers who now have a standard set of figures to work with. We know for example the bullet diameter of a .223 Remington cartridge and groove diameter of a .223 Remington barrel is .224. What? Yes, even with standardisation the confusion persists.

Globally, the convention for cartridge measurement can be in imperial units such as .264” or metric as in 6.5mm and the US used imperial measurements exclusively until recent times when European calibres began to proliferate the American shooting scene. Many are familiar with the pistol calibre simply referred to as the .38 and generally speaking, to a pistol shooter, the number 38 means either .38 Special (revolver round) or .38 Super (hand-loading pistol round). Here the 38 refers to the bullet diameter of .38 of an inch which are actually .357” and .355” respectively.

To a black powder rifle shooter it may be a .38-55, meaning a .38” calibre bullet sitting in a case holding 55 grains of black powder, while to a single action shooter it may be a .38-40, again a .38” diameter bullet in a cartridge case holding 40 grains of black powder, or does it? More on that later.

The same cartridge labelling conventions apply to all other calibres - .308 Winchester being a bullet diameter followed by a name to indicate this is a proprietary cartridge of Winchester. The same cartridge may have more than one name and in its military form the .308 Winchester is the 7.62x51mm NATO (where 7.62 is bullet diameter and 51 the length of the case in millimetres).

The main photo shows a line-up of cartridges which all have two things in common - all are named 38 something yet none have a bullet calibre of .38”, the descriptions of these cartridges taken from their headstamps or packets. From left: .380 Corto, .38 Auto, .38 Short Colt, .38 Super, .38 Special, .38 WCF, 38-40 Remington-Hepburn, .38-50 Remington-Hepburn, .38-45 Bullard, .38 Extra Long, .380 Long, .38 Long Colt, .38 ACP and .38 S&W.

There are many more in the 38 family not on display here but for the sake of the exercise let’s look at these examples more closely. Also note the additional zeros as in the .380 Corto and .380 Long are redundant, although the manufacturers probably wanted to make the zero a point of distinction from other cartridge makers.

Confusion persists

Some of the rounds pictured have the same dimensions but different names, the .38 S&W (Smith & Wesson) also known as the .38/200 when it was used in Commonwealth service during World War II. Three cartridges in the main photo, the .38 Auto, .38 ACP and .38 Super, share the same dimensions with minor differences in the rims. The most important aspect to this line-up of 14 cartridges is none of them have a .38” diameter or calibre bullet, the closest being the .38-50 Remington-Hepburn at .376”, the rest ranging between .355” and .375” and, for some reason unknown to me, the .38 WCF (also known as .38-40 Winchester) has a bullet measuring .401”. Maybe they should have called it the .40-38.

As can be seen, ammunition and firearms manufacturers simply picked a ‘ballpark’ number in describing their invention, 38 being a nice round figure which rolls off the tongue and, in the early days at least, no one was forecasting the possibility of future confusion.

On a personal note I’d like to see the word calibre used to describe the diameter of a bullet and groove diameter of a rifled barrel, leaving cartridge or ammunition to describe what is fired from a particular firearm. Price tags in gunshops and official registry documents could follow the same practice so when someone asks: ‘What calibre is that rifle?’ and the answer: ‘6.5’, a follow-up question then has to be asked: ‘6.5 what?’

The passing of some elements of the Ammunition Bill in NSW a couple of years ago highlighted issues around how ammunition for a particular firearm is described, registration certificates issued by NSW Firearms Registry listing: Popular Calibre Name. In NSW, under the Ammunition Bill, shooters looking to buy ammunition for handguns must produce their registration certificate as proof they do, in fact, own a handgun for which the ammunition is required. Presenting a registration certificate to gunshop staff simply marked .357 would imply .357 Magnum ammunition is required, though the buyer may want .38 Special ammo instead.

This situation is now being rectified and the registry will issue a new certificate, on request, with correct ammunition description. Of course it’s the dealers who initially describe the firearm on their paperwork to the registry and registry copy that information to the buyer’s registration certificate verbatim, without questioning what ammunition is actually used in that firearm. In this example, the new ammunition description now, more correctly, reads: 38 Special/.357 Magnum. Are we clear?

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