What is the term for grooves in the barrel of a firearm designed to improve the bullet's range and accuracy?

The term for grooves in the barrel of a firearm designed to improve the bullet's range and accuracy is known as rifling. Rifling consists of a series of helical grooves cut into the bore of the barrel that impart a spin to the bullet as it is fired. This spin stabilizes the bullet in flight, leading to improved accuracy and range. The design of the rifling—its depth, width, and twist rate—can all influence the performance of the bullet, making it a critical feature in the engineering of firearms.

Other terms such as grooving or barrel lining do not specifically refer to the intentional design that enhances bullet trajectory and control. While rifling marks may describe the impressions left on a bullet by the grooves, the key term denoting the grooves themselves that facilitate improved ballistic performance is rifling. This distinction highlights the precision involved in firearm design, as adequate rifling can significantly affect shooting outcomes.