What is unique about rifle barrels in comparison to shotguns regarding grooves?

Rifles are equipped with a feature known as rifling, which consists of spiral grooves cut into the interior of the barrel. This rifling is designed to impart a spin on the bullet as it travels down the barrel, stabilizing its flight and improving accuracy over longer distances. The grooves serve to grip the bullet, allowing it to maintain a straight trajectory once it exits the barrel.

In contrast, shotgun barrels are typically smooth. They do not have rifling, as shotguns are primarily designed to fire a spread of shot or larger projectiles, which do not require the same level of spin for stabilization as bullets do. This difference in design between the two types of firearms illustrates how rifling in rifle barrels is essential for precision shooting, while the smooth design of shotguns is suited for a different type of shooting scenario.