The Times tested the blast waves of several popular civilian guns at an indoor range and found that repeated firing could add up to potentially harmful exposure.
The 1911 uses .45 and .45 is a subsonic ammunition, which means its muzzle velocity is below the speed to break the sound barrier, and doesn’t produce a supersonic crack. The delisle carbine was a bolt action integrally suppressed rifle made from the Lee Enfield, re-chambered for .45 from .303 due to its subsonic nature and is known to be one of the quietest firearms to exist, and the round doesn’t produce a loud crack.
Where 9mm isn’t subsonic, it has a higher muzzle velocity and therefore would generate more atmospheric pressure, and a supersonic crack. This is why the world famous MP5SD, known for its total silence, was revolutionary. people say the only thing you hear is the bolt cycling. It has a perforated barrel that leaks enough of the gases out of the barrel into the suppressor. Infact, it leaks enough to actually prevent the 9mm from achieving supersonic speeds. They designed it this way so it doesn’t have to use ammunition that is specifically filled to be subsonic, or to use a round that is inherently subsonic like .45.
So that is two examples of gun design history around trying to be quiet with ammunition, one designed around the ammo, and one around the gun.
The 1911 uses .45 and .45 is a subsonic ammunition, which means its muzzle velocity is below the speed to break the sound barrier, and doesn’t produce a supersonic crack. The delisle carbine was a bolt action integrally suppressed rifle made from the Lee Enfield, re-chambered for .45 from .303 due to its subsonic nature and is known to be one of the quietest firearms to exist, and the round doesn’t produce a loud crack.
Where 9mm isn’t subsonic, it has a higher muzzle velocity and therefore would generate more atmospheric pressure, and a supersonic crack. This is why the world famous MP5SD, known for its total silence, was revolutionary. people say the only thing you hear is the bolt cycling. It has a perforated barrel that leaks enough of the gases out of the barrel into the suppressor. Infact, it leaks enough to actually prevent the 9mm from achieving supersonic speeds. They designed it this way so it doesn’t have to use ammunition that is specifically filled to be subsonic, or to use a round that is inherently subsonic like .45.
So that is two examples of gun design history around trying to be quiet with ammunition, one designed around the ammo, and one around the gun.