What is the purpose of rifling in a firearm?

Rifling in a firearm is a critical design feature that consists of spiral grooves cut into the interior of the barrel. The primary purpose of these grooves is to impart a spin to the bullet as it travels down the barrel. This spin stabilizes the bullet during flight, significantly enhancing both its accuracy and range. When a bullet is spun, it follows a more stable trajectory, which helps it to resist the forces of gravity and wind better than a non-spinning projectile. The increased stability leads to more consistent and precise shots, making rifling a fundamental aspect of most rifles and many handguns.

Options that suggest increasing the weapon's volume, enhancing appearance, or reducing the bullet's weight do not align with the primary functional purpose of rifling, which is directly related to the performance of the bullet in terms of accuracy and distance.