Not till the mid-1800s was a weapon invented that was useful, In most cases mechanically reputable, and could be reloaded somewhat immediately. The best identified example was the Gatling Gun. It had been the invention of Richard J. Confronted with the dominance in the machine gun, the belligerents sought methods https://machguns.com/product/m10-9mm-rpb-mac-excellent-b2475/