How loud is a silenced gun?

Answer 1

They're not as silent as they're made out to be in the movies. For one, there'll be the noise of the action being worked as it cycles after being fired. Additionally, while a suppressor will reduce the noise emissions of the expanding gases which leave the barrel, they do nothing to silence a projectile as it goes supersonic, which is why suppressors aren't fully effective unless they're firing subsonic ammunition. See the related link at the bottom for a video taken from the 2009 AAC Suppressor Shoot, and it should give you a better idea.