The CB is much quieter in a longer barrel with a closed action - lever, bolt, pump; but not an auto. It is the rapidly expanding high pressure gasses that make the noise.

If you shoot CB's in a handgun they will not be as quiet as if you shoot them in a locked breech rifle. You will also find that some gas will escape out of the breech of a semiauto and therefore the autos will not be as quiet as the others.

So if you want to be quiet when shooting a 22, then get yourself a nice 22 rifle with a long barrel and a closed breech and you will be right on track. I use an older Remington bolt action single shot with a 24" barrel and a scope and it is deadly on rabbits in my wife's garden.

Ward