The .45 ACP cartridge is known for its ability to function at velocities below the speed of sound, typically around 1,125 feet per second. Standard loadings often achieve this, making them inherently quieter than supersonic rounds. For example, a 230-grain bullet propelled by a standard powder charge will generally remain subsonic.
This characteristic is valuable for suppressed firearm use, as it eliminates the sharp crack produced by a projectile breaking the sound barrier, enhancing stealth and reducing noise pollution. Historically, subsonic performance was a key consideration in the .45 ACP’s development in the early 20th century, contributing to its adoption by military and law enforcement agencies. The inherent subsonic capability, combined with heavier bullet weights, also influenced its reputation for effective stopping power.