This computer animation, created by Demonstratives, Inc., shows how the 1853 Robbins & Lawrence rifling machine cut the rifled grooves in a gun barrel.
In the early 1850s, Henry Stone designed a rifling machine that took a smoothbore gun barrel and cut parallel spiral grooves inside the barrel. This technology dramatically changed the accuracy in which bullets were fired. A bullet shot out of a smoothbore barrel would fly haphazardly, but the spiral grooves in a rifled barrel caused the bullet to spin as it flew, making it much more accurate at a greater distance. This technique was used in the Special Model 1861 rifle musket used by the Union Army. Gun manufacturing during the Civil War contributed to the change in military tactics that would impact the way in which future wars were fought.