Why are many older cartridges identified by two-number designations? Prior to the turn of the 20th century, two double-digit—three-digit in some cases—numbers separated by a hyphen identified many American small arms cartridges, especially rifle-caliber, .25-20, .30-30, .38-40, .45-70, and .50-115 for example, and were usually followed by the manufacturer’s name or some other identifying word. Keep in mind though that some revolvers were chambered for certain shorter cased rifle-caliber rounds, .32-20. .38-40, .44-40, for example.
The first digit is the cartridge’s bullet caliber in hundredth of an inch (usually rounded out) and the second is the weight of black powder propellant in grains. Even after smokeless powder was introduced just before the turn of the century some newly developed cartridges were still designated with the two-number system.
The left cartridge is the original .45 Colt (sometimes called the Long Colt). The center is the .45 S&W for the Schofield revolver. The Army adopted both revolvers, but issued only the .45 S&W so it could be used in both revolvers. The right cartridge is also a .45 Colt, but made in the same length as the .45 S&W, also called the .45 Colt Government. It will chamber in both revolvers, but the .45 Long Colt cannot be fired in the Schofield revolver.
Some of these were loaded only with smokeless propellant. The .30-40 Krag, for example, adopted by the US Army in 1892. It was never loaded with black powder, only smokeless. The “40” was the black powder equivalent of its smokeless propellant loading. The famous .30-30 Winchester was also loaded with smokeless powder, but in this case the second “30” was apparently the sole instance when it meant 30 grains of smokeless powder and not black powder. Some exceptions will be found, such as the .30-06, in which the second digit has another meaning, but that’s a different story.
As an aside, smokeless powder, Poudre B, was invented by a French chemist, Paul-Marie-Eugène Vieille (1854-1934), in 1884. It was made by dissolving nitrocellulose in ether and alcohol until it became a gelatinous mass, which was rolled into sheets and cut into flakes after the solvent evaporated. The first military cartridge using smokeless powder was the French 8x50mmR Lebel of 1886. Much improved nitrocellulose single-base propellants were later developed by Alfred B. Nobel (1833-96), who also patented dynamite in 1867 and established the Nobel Prize. Other smokeless propellants were also developed such as cordite and ballistite. The oft used description, “the smell of burnt cordite,” is only accurate if referring to British Commonwealth weapons from World War II and earlier.
A three-number system identified some cartridges with the third number being three-digit, for example, .45-70-500 and .45-70-405. The third number was the bullet weight in grains. In the case of the different .45-70 Government (aka .45-70 Springfield) loadings, the 405-grain bullet was the first issued in 1873. In 1882 the 500-grain bullet was adopted to achieve longer range. There was also a .45-55-405 dating from 1873, which had the lighter bullet plus a much lighter powder charge for carbines in order to reduce the recoil. All three rounds were interchangeable in any of the weapons, but a rifle’s sight would not have been graduated for the carbine’s lighter bullet and charge and vice versa.
Earlier than this when muzzle-loading ammunition was used, paper or linen cartridges and balls (even pointed bullets were called balls) were identified on cartons and packets by the make of the weapon and the caliber designated, for example, “Calibre 52-100 for Sharps Carbine,” meaning 52/100th of an inch caliber; often without the decimal point.
Another early two-digit cartridge designation oddity was the “.56” Spencer rimfire series of the 1860s. The first “56” in the designation is the diameter of the base of the cartridge above the rim. The second number is not the propellant weight, but the bullet’s caliber and it was available in four chamberings: .56-56, .56-52, .56-50, and .56-46. The cartridge base diameter was 0.560-inch on all of these, but the cases tapered to the smaller calibers identified by the second number. The .56-50 could be fired in .50-70 Springfield rifles.
The widely variety of Sharps rifle cartridges could be confusing with multiple types in .44, .45, and .50-calibers identified by bullet caliber, black powder weight in grains, and bullet weight in grains. The number below each cartridge is the case length, not the overall cartridge length.
So, now you are probably thoroughly confused. The point is that there are a lot of exceptions and different ways of designating cartridges. A cowpoke or gunslinger could not simply walk into a mercantile or general store and say, “Gibme a box of forty-four.” There were about a dozen different .44-caliber cartridges commonly in use in the last half of the 1800s, plus a few odd ones. Very few were interchangeable. The guns themselves were often poorly marked as to the caliber, not like today when the caliber is more precisely marked. A gun might be marked simply “.44”.
The easy way out is to simply not mention the calibers of guns or be vague, saying it’s a .45, but not which one. There’s nothing wrong with that.
What is worse is to use the wrong cartridge or to incorrectly show a cartridge’s designation. For example, it’s a “.44-40”, not a “44/40”. It will damage credibility with those who are familiar with weapons.
The preceding article is expanded from an article in The Big Book of Gun Trivia: Everything you want to know, don't want to know, and don't know you need to know.