Eric Raymond considers himself an expert on the history of the duel of honor:
First, the undisputed facts: dueling began a steep decline in the early 1840s and was effectively extinct in English-speaking countries by 1870, with a partial exception for American frontier regions where it lasted two decades longer. Elsewhere in Europe the code duello retained some social force until World War I.
This was actually a rather swift end for a body of custom that had emerged in its modern form around 1500 but had roots in the judicial duels of the Dark Ages a thousand years before. The conventional accounts attribute it to a mix of two causes: (a) a broad change in moral sentiments about violence and civilized behavior, and (b) increasing assertion of a state monopoly on legal violence.
I don’t think these factors were entirely negligible, but I think there was something else going on that was at least as important, if not more so, and has been entirely missed by (other) historians. I first got to it when I noticed that the date of the early-Victorian law forbidding dueling by British military officers – 1844 – almost coincided with (following by perhaps a year or two) the general availability of percussion-cap pistols.
The dominant weapons of the “modern” duel of honor, as it emerged in the Renaissance from judicial and chivalric dueling, had always been swords and pistols. To get why percussion-cap pistols were a big deal, you have to understand that loose-powder pistols were terribly unreliable in damp weather and had a serious charge-containment problem that limited the amount of oomph they could put behind the ball.
This is why early-modern swashbucklers carried both swords and pistols; your danged pistol might very well simply not fire after exposure to damp northern European weather. It’s also why percussion-cap pistols, which seal the
powderpriming charge inside a brass cap, were first developed for naval use, the prototype being Sea Service pistols of the Napoleonic era. But there was a serious cost issue with those: each cap had to be made by hand at eye-watering expense.
Then, in the early 1840s, enterprising gunsmiths figured out how to mass-produce percussion caps with machines. And this, I believe, is what actually killed the duel. Here’s how it happened…
First, the availability of all-weather pistols put an end to practical swordfighting almost immediately. One sidearm would do rather than two. Second, dueling pistols suddenly became tremendously more reliable and somewhat more lethal. When smokeless powder became generally available in the 1880s they took another jump upwards in lethality.
Moral sentiments and state power may have been causes, but I am pretty convinced that they had room to operate because a duel of honor in 1889 was a far more dangerous proposition than it had been in 1839. Swords were effectively out of play by the latter date, pistols no longer sputtered in bad weather (allowing seconds to declare that “honor had been satisfied”) and the expected lethality of a bullet hit had gone way up due to the increased velocity of smokeless-powder rounds.
I’m not sure that’s a new idea.