Projectiles expelled from firearms at velocities exceeding the speed of sound create a phenomenon where the projectile arrives at a target before the sound of its discharge. This supersonic speed, typically measured in feet per second (fps) or meters per second (m/s), allows the projectile to traverse a distance rapidly. For example, a common 9mm round can travel at approximately 1200 fps, surpassing the speed of sound at sea level, which is roughly 1125 fps.
This characteristic has significant implications in various fields. In military and law enforcement contexts, the rapid delivery of a projectile is crucial for effective engagement. Historically, the development of projectiles with increased velocities has been a continuous pursuit to enhance their effectiveness and range. Furthermore, understanding the principles of supersonic projectile motion is vital in ballistics research, forensic analysis, and the design of safer and more effective firearm systems.