Itty-bitty handguns aren't the only things you can silence. Giant freaking shotguns can even be fitted with a special silencer that renders them inaudible in quiet suburban neighborhoods.
Also, while silencers look all slick and expensive and fancy, Hollywood says pretty much any long, hollow tube will do the job. Grab a two-liter, stuff it with socks or something, and you can be just as dangerous as Mark Wahlberg in Shooter.
Exploding gunpowder is loud. Really loud. As loud as a jet engine. A little metal tube won't do a whole lot to stop that. This is what a suppressed handgun actually sounds like:
If you can't watch the video, let us sum it up: It still sounds like a freaking handgun. It does not make a soft phut that you could mistake for a kitten landing on a pillow.
An unsilenced gunshot is around 140 to 160 decibels--that's in the range where hearing it once can permanently damage your ears. If you've never had a gun go off next to you, trust us when we say it's loud enough that your whole body will flinch at the sound of it. A silencer can get that all the way down to 120 or 130 decibles, aka the sound of a jackhammer. Still loud enough to cause physical pain if it's close enough to you.