In the United States cartridge names are collected, standardized, and published by the Sporting Arms and Ammunition Manufacturers' Institute (SAAMI). The ultimate goal is safety: Important cartridge identifiers should be consistent with caliber markings on firearms. This is to avoid unsafe combinations that could cause damage or personal injury. SAAMI considers cartridge naming a marketing function as long as safe usage is not compromised.
As I pointed out last month, cartridge names are primarily trade names and seldom provide more than only the most basic technical information.
[Editor's Note: Because SAAMI's method of notating cartridge names does not utilize the decimal point that has been a standard in firearms publishing for decades, this month's installment of "The Ballistician" column will defer to SAAMI style.]
The Days of Blackpowder
When blackpowder cartridges were in their heyday, the United States had a naming system that showed some promise and at least suggested a level of performance in the name. With blackpowder, you got more velocity by adding more powder. All other things being equal, a cartridge loaded with 70 grains of blackpowder would produce higher velocity than one with 60 grains. To make room for massive amounts of blackpowder, cartridge case lengths increased up to 3.25 inches.
That system used at least two numbers. The first was the bore diameter of the firearm. Bore diameter is defined as that of the drill used to create the barrel's first drill hole, not the final rifled diameter. The second number was the blackpowder charge weight in grains (grains avoirdupois- 437.5 grains to the ounce). Often a maker's name was appended after the numbers- for example: 45-70 Government, 38-55 Winchester, 50-90 Sharps, 44-77 Remington, 40-63 Ballard. Sometimes a third number was added to show bullet weight, as in Winchester's 50-100-450.
The powder weight numbers were not always accurate. Probably, they were accurate when the cartridges were invented, but as new bullet weights were added and cartridge case improvements decreased internal capacities, actual charge weights went down. The last blackpowder versions of the 38-55 Winchester held only 48 grains of blackpowder.
This system did not eliminate mix-ups. The 40-60 Marlin and the 40-65 Winchester were virtually the same cartridge and interchangeable. However, the 40-60 Marlin and the 40-60 Winchester are different and not interchangeable. The 40-70 Winchester is nothing like either variant of the 40-70 Sharps. Speaking of Sharps, the company had a series of .40-caliber cartridges: 40-50, 40-70, and 40-90. Both a straight-walled and a bottlenecked version of each was offered.
This system tried to transition into the smokeless propellant era. Both the 30-30 Winchester and 30-40 Krag were originally loaded with smokeless powder. However, energy release rates of the new fuels varied by propellant maker and model, rendering the use of a particular charge weight in a name a moot point. If the cartridge made it to smokeless use, the old charge weight simply became part of the name- for example, the 38-55 and the 45-70.
The British Way
British practices largely omitted the propellant and bullet weight info the U.S. used. They often used the maker's name or the parent cartridge's name that a newer round evolved from, but their system differed from U.S. practices. Where we put the new bullet diameter first and the parent cartridge second, say, the 30-378 Weatherby, our English friends swapped them. The famous 577-450 Martini-Henry military cartridge was .45 caliber and derived from a much older .577-caliber straight-case cartridge.
The British liked the term "Express" to indicate higher speed, but competition in the market affected its use. One popular medium-bore rifle was the 318 Westley-Richards Accelerated Express. I guess it was even more "Express" than the other "Express" cartridges.
Metric Europe seemed to have more control over cartridge identifiers with fewer apparent market influences. They used the bore diameter in millimeters (1mm = 0.04 inch) followed by an "x" and added the cartridge case length, also in millimeters. In English we read the "x" as "by." For the 7x57mm we say "seven by fifty-seven." Company or inventor names- Mauser, Brenneke, and Mannlicher-Schoenauer, et. al.- were commonly added. If the cartridge had a rim, an "R" was added, such as 9.3x74Rmm. Current Euro-cartridge names, however, can look more like U.S. names.
Magnum as a Moniker
And then there's the "Magnum" name. People still think it has a precise technical meaning. SAAMI defines "Magnum" as this:
"A term commonly used to describe a rimfire or centerfire cartridge, or shotshell, that is larger, contains more shot, or produces higher velocity than standard cartridges or shells of a given caliber, or gauge."
These are vague, nontechnical terms. There is no mention of how much larger, how much more shot, or how much higher velocity. Many cartridges fall nicely within the definition, such as the 22 Winchester Magnum Rimfire: bigger case with more velocity than other 22 rimfire cartridges.
Some cartridges that are called "Magnums" fail to meet that vague definition. The 25 Winchester Super Short Magnum is smaller and produces a little less velocity than the venerable "non-Magnum" 25-06 Remington. The 357 Maximum is larger and produces more velocity than the 357 Magnum. Same thing happens when you compare the 458 Winchester Magnum to the newer "non-Magnum" 458 Lott. "Magnum" has evolved into a marketing name. We just have to accept it.
At one point the U.S. naming system showed signs of becoming more useful. Names used the bullet diameter, not the smaller bore diameter. The names 243 Winchester, 257 Roberts, 284 and 308 Winchester, 338 Federal, and 375 Ruger accurately reflect actual bullet diameter. However, the exceptions continue. For example, the 327 Federal uses 0.313-inch bullets, the 460 S&W Magnum uses 0.452-inch bullets, and the 325 Winchester uses 0.323-inch bullets.
I suspect U.S. cartridge developers won't introduce a more technically accurate naming system. Frankly, I don't care. When I hear great names like Roberts, Casull, Whelen, Weatherby, Rigby, and Holland & Holland on cartridges, I appreciate our sport's rich heritage even more.