Why is a handgun round becomes less effective than a rifle bullet over long distances?

A handgun round becomes less effective than a rifle bullet over long distances primarily due to differences in velocity and design. Handgun rounds typically have lower muzzle velocities and less aerodynamic profiles, leading to greater bullet drop and loss of energy over distance. In contrast, rifle bullets are designed for higher velocities and streamlined shapes, allowing them to maintain their velocity and energy better as they travel farther. This results in rifle bullets having greater penetration, accuracy, and stopping power at long ranges compared to handguns.