Before a “big shot” was a person — like in “Unless the memory plays us a trick, Al Capone is the ‘big shot’ of Chicago gangland” (1930), it was literally a shot. One that was, and I suppose this would be obvious, comparatively large.
Guns were probably invented in China around 1000 CE. They took another four centuries to show up in Europe and in European languages, and at first they weren’t called “guns.” In fact, the word “gun” comes from just one weapon in particular, and it wasn’t even anything we’d call a “gun.” It was a ballista, sort of a giant crossbow. They had a huge one in Windsor Castle, and named it “Domina Gunilda.” That eventually got shortened to “gunne”, and finally to “gun”.
Guns, as everybody knows, shoot. And “shot” was a word that was already available in the 1400s when guns showed up; it’s from Old English. A “shot” was any rapid motion, like throwing a rock or releasing an arrow. It’s interesting how difficult it is to find synonyms for “shot” and “shoot;” “shooting a gun” and “shooting an arrow” are so well established in the language that there aren’t that many other ways people tend to express the idea.
However, “shot” has been used in lots of different ways over the centuries, from “shooting pain” to “take a shot” meaning make an attempt. It’s been used in weaving, farming (with a plow), bad luck, a navigational observation at sea, a medical treatment, and so forth. You can call the shots, exchange shots, take a shot (which can be good or cheap or in the dark), and — now we’re finally getting somewhere — in the 1600s a “great shot” was a person’s primary goal. “The great shott of Cromwell and Vane is to have a libertie for all religions.” (1644)
At the same time, the development of firearms had introduced “great shot” and “small shot” into the language as, sort of, technical terms: “A long and doubtfull fight, both with great and small shot.” (1632) Great shot would be a cannon ball, while small shot fit into a musket. When “gun” entered the language, the same adjectives applied; there were “small guns” and “great guns,” or cannons. (This doesn’t explain the phrase “going great guns,” which means going fast, since cannons generally don’t travel rapidly.)
In the 1800s, the term “big shot” showed up. It wasn’t at first a direct replacement for “great shot,” though. It meant something else — mining and excavation were using new substances like “dynamite,” which was invented in 1860. A “big shot” was either a large blast or a series blasts set up in an automatic sequence. A 1905 story in the Washington Post described it: “…to personally superintend the preparations for what is called a ‘big shot’ to be fired to-morrow morning. A ‘big shot’ consists of a series of blasts, the holes having been drilled in a row, and the charges being set off simultaneously by an electric spark.”
That’s the evolution of the literal kind of “big shot”. When there’s an exceptionally evocative term like “big shot” available, figurative use doesn’t lag far behind. By 1911, you could see notices like this one from Ohio: “It is now past the middle of May and we are going to take one ‘BIG SHOT’ at the remainder of the Stock at HALF and LESS.” And also from Ohio, in 1929: “One of them is just as likely to win the series as one of the ‘big shots’.”
And with that, we’re back to where we started, with the big shots of their respective fields, including crime bosses. One thing the baddies would seldom do, I suppose, was to “stand shot,” which just meant to pay: “Are you to stand shot to all this good liquor?” (1821).
