Question: Why is it that when you shoot a gun you hear something but when you attach a suppressor to the gun it makes a smooth sound

Justin Lawley answered on 22 Mar 2012:

This is a question that one of the physicists may answer better. But, I think I know the answer so ill give it a go. when you fire a bullet out of a gun the pressure behind the bullet is very large and this pressure exits a very small barrel and makes a noise similar to popping a cork on a bottle of champagne. The supressor is larger than the barrel of the gun and adds length. So as the bullet exits the barrel of the gun the pressure is released througout the supressor so when the bullet finally exits the supressor the pressure behind it is much lower and makes less noise. So the bigger the suppressor the quiter the gun. Who says physics isnt awesome…