The question of whether all .45 ACP ammunition is subsonic addresses a common misconception. Subsonic ammunition, by definition, travels slower than the speed of sound, typically around 1,125 feet per second (fps) at sea level. While some .45 ACP cartridges are designed for subsonic velocities, many standard and +P loads exceed this threshold, making them supersonic. For instance, a standard 230-grain .45 ACP round may have a muzzle velocity exceeding 800 fps, while some defensive loads can reach over 1,000 fps. Ammunition manufacturers specify muzzle velocities on their packaging, allowing for clear identification of subsonic options.
Understanding the velocity of ammunition is critical for several reasons. Subsonic rounds are often preferred when using suppressors, as they minimize the supersonic crack, a loud noise produced by projectiles breaking the sound barrier. Furthermore, subsonic loads can offer distinct advantages in specific shooting disciplines, such as reduced recoil and quieter report. Historically, subsonic .45 ACP loads were developed primarily for military applications involving suppressed weapons. However, the broader availability of subsonic options now caters to civilian uses including recreational shooting, hunting, and home defense.