: The main "pop" or "bang" caused by the rapid expansion of gases as the bullet exits the barrel.

The acoustic signature of a 9mm consists of three primary layers:

In professional sound design, a single recording rarely suffices. Designers typically layer three distinct frequency bands to create a cinematic 9mm shot:

: If the 9mm round is supersonic (traveling over ~1,125 fps), it produces a sharp, whip-like crack that follows the initial blast. Sound Design & Layering