Subsonic ammunition

In this instance, heavier bullets are loaded in standard ammunition, which reduces muzzle velocity below the speed of sound.

For example, the traditional American military standard .45 ACP ammunition load of a 14.9 g (230 gr) bullet at 259 m/s (850 ft/s), is naturally subsonic.

The peak sound pressure levels of a Remington 700 .223 caliber bolt-action rifle firing high-velocity (supersonic) ammunition using a GEMTECH G5-5.56 suppressor.

The peak sound pressure levels of a Remington 700 .223 caliber bolt-action rifle firing low-velocity (subsonic) ammunition using a GEMTECH G5-5.56 suppressor.

Compared to the high-velocity (supersonic) unsuppressed condition, the combination of subsonic low-velocity ammunition and a firearm suppressor provided reductions of 45, 38, 40, and 48 dB, peak sound pressure level at the muzzle, left, right ears and behind the shooter, respectively.