The AR-15 is a highly versatile, semi-automatic rifle platform popular for its modularity and adaptability. It works with a wide range of parts, including barrels, upper and lower receivers, bolt carrier groups, handguards, buffer tubes, stocks, magazines, triggers, and sights. The AR-15 supports various calibers, making it ideal for target shooting, hunting, home defense, and custom builds. Its compatibility with countless aftermarket components allows shooters and builders to easily customize and upgrade their rifles for any application.