Hard Magic: French Edition
This is the cover art and design for the French edition of Hard Magic , which is book one of the Grimnoir Chronicles by Larry Correia. This French language edition will be published by L’Atalante in a few months under the title Magie Brute.
The story is set in an alternate 1930’s America where certain people possess magical abilities and features an eclectic cast of characters from ninjas to gangsters and secret societies. As the book has a pulpy feel to it, I looked at a lot of old pulp covers for inspiration for both the artwork and design.
As you can see from my initial rough sketch below, I’d originally intended for the main character to be holding more of a typical looking gun of the period but then the publisher suggested replacing it with a Gatling gun instead to show the great force of the central character (his magical ability is to control gravity and as such can lift very heavy objects). I think the inclusion of the Gatling, although an anachronism, provided greater visual impact and does the job of showing the power of the character as intended.
Vincent Chong Illustration & Design Blog 
Well… that you specifically chose a GE/Dillon minigun is an anachronism (it was designed in 1959 originally); but actually, they had gatling guns in the 30s. In fact, they had electrically driven gatling guns before modern machineguns.
The modern machine gun was invented by Hiram Maxim in 1884, and basically perfected by John Browning (a character in the book funny enough) in 1918-1919. That same basic gun is still in service by the by, as the M2 heavy machine gun.
The gatling gun was invented by a dentist named Richard Gatling in 1861, and were still in use around the world in the 1930s. They even had an electric powered one by 1893, that looked similar in many ways to the GE minigun; though they were generally thought of as obsolete by the teens, with the development of the maxim gun (and it’s offshoots), and the Browning machine guns.
Many gatling guns were quite attractive and “steampunkish”, with bright brasswork etc… One of those would have looked quite spectacular for the cover really.
If you wanted to be period accurate, and reference the story itself (through Browning), you could have had Sullivan firing a Browning Automatic Rifle (which he does in the story, and which weighs about 20lbs), or even a Ma Deuce heavy machine gun (which weighs about 100 lbs, plus ammo), vs the GE minigun (which actually “only” weighs 70lbs).
Really though, an electrically operated hand held minigun with a modern frame, carrying handle etc… really isn’t much of an anachronism. It’s entirely possible with the technology of the day, and in fact for anti-aircraft, or aircraft mounting, it makes sense they might use them.
I’d have thought a Lewis gun with the water jacket would have plenty of presence. Perhaps not as much as the Dillon, but would be more period appropriate.
Lewis gun would have made a ton of sense, since Jake uses it in the story (Jake is the big guy with the minigun.) But I’m not complaining. The gun is the only jarring element; otherwise, I like this cover a lot better than the one on my American copy, to be honest.