Originally Posted by
okie
I think the best way to visualize it is to think of the gas coming out of the barrel like water comes out of a hose. That concentrated, high pressure column is what hits the atmosphere and makes the waves that you hear as sound. By breaking up that column, you lower the pressure and velocity of the gas before it hits the atmosphere, and therefore lower the resulting pressure wave.
Problem is, you can't put anything in that column's path to break it up, because that's where the bullet comes out, too. So you have to create a pressure differential in the can to encourage the gas to flow in one direction, causing the column to bend slightly, driving it down into the baffles.
People have tried alternate methods of interrupting the column, namely by using ports in the baffles to try and create jets of gas that aimed at the column are intended to disperse it. The problem with that is that the gas routed through those ports is already at a much lower pressure, so it's like trying to break up the laminar flow out of a fire hose with a squirt gun.