Gatling gun

Richard Gatling, a physician who never practiced medicine, invented the first practical rapid-fire weapon with a paradoxical goal: to reduce casualties. His logic, strange as it sounds, was that if fewer soldiers could generate more firepower, armies would shrink and fewer men would be exposed to the battlefield diseases that killed more soldiers than bullets did. The weapon he created in 1861 would instead multiply the lethality of warfare.

The adjacent possible for the Gatling gun required metallic cartridges that could be reliably fed into a mechanism, and the industrial capacity to manufacture precision components. Gatling's design used six barrels arranged in a circle, rotated by a hand crank. As the operator turned the crank, each barrel cycled through loading, firing, and ejecting. The rotating design solved the overheating problem that plagued single-barrel weapons—each barrel cooled while the others fired.

Gatling patented his 'Revolving Battery-Gun' on November 4, 1862. The earliest version fired about 200 rounds per minute using paper cartridges. When brass cartridges became available, later models achieved 400 rounds per minute—a rate of fire no infantry formation could match. A single Gatling gun crew could deliver more firepower than an entire company of riflemen.

Despite its potential, the Union Army largely ignored the Gatling gun during the Civil War. Gatling promoted his weapon energetically, even appealing directly to President Lincoln, but military bureaucracy moved slowly and the weapon arrived too late to see significant action. Only a handful were purchased privately by individual commanders. The gun's real adoption came after the war, when the U.S. Army and navies worldwide recognized its value.

The Gatling gun's rotating-barrel principle proved so effective that General Electric revived it a century later for the M61 Vulcan aircraft cannon. Where Gatling's hand crank produced 400 rounds per minute, the electric-powered Vulcan fires 6,000. The engineering insight—that multiple barrels rotating through the firing cycle could achieve rates of fire impossible for a single barrel—remains as valid in jet fighters as it was in the 1860s.