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. Specific reductions depend on the ammunition and suppressor. Main article: Suppressor § Subsonic ammunition and reduced sonic signatureĬombined with firearm sound suppressors, subsonic ammunition may significantly reduce sound levels compared to normal ammunition. These are designed from the start as dedicated subsonic projectile systems. 45 ACP ammunition load, of a 230 grain bullet at 850 feet per second, is naturally subsonic.Īlternatively, specialized firearms and ammunition may be used to optimize total subsonic ammunition effectiveness. For example, the traditional American military standard. Some ammunition types were inherently designed with heavier, slower standard bullet weights and velocities. Subsonic ammunition with normal bullet weights often fails to properly function in such firearms. Subsonic loads for 9mm commonly use 9.5 grams (147 gr) bullets at velocities of 300 metres per second (980 ft/s).įor these ammunition loads, balancing bullet weight and velocity are required to ensure that the ammunition will still reliably cycle semi-automatic firearms. In this instance, heavier bullets are loaded in standard ammunition, which reduces muzzle velocity below the speed of sound.Īs an example, the very common 9×19mm Parabellum standard military round is a 7.5 grams (116 gr) bullet at velocities typically around 360 metres per second (1,200 ft/s). Standard calibers Subsonic versions of standard rounds Some subsonic ammunition is used in non-suppressed firearms to gain the advantages of heavier bullet weights.

Subsonic ammunition usually uses heavier bullets to retain as much energy as possible at the lower velocities. This avoids the supersonic shockwave or 'crack' of a supersonic bullet, which, particularly for suppressed firearms, influences the loudness of the shot. Subsonic ammunitions are ammunitions designed to operate at velocities below the speed of sound, which at standard conditions is 340.29 m/s (1,116.4 ft/s) or Mach 1. Ammunition designed to operate at velocities below the speed of sound

22lr subsonic ammo range