None of the quiet rounds are quiet in a handgun. I've shot CCI Quiet 22., Remington CB caps, and Aguila Super Colibri's in both handguns and rifles. In a handgun they are still loud enough to attract attention. In a rifle you can shoot it right outside someones window and they wont notice it.
They do not cycle firearms. I always use a bolt rifle and make sure each shot leaves the barrel.
I've shot them outside my house and my neighbor was home. She asked if I was shooting a BB gun. I said yes and put it away and got a pellet gun out just in case.
I have also used them to shoot woodchucks at close range and they died with one shot. I did shoot them in the head.
Oh and they now make quiet-22 fragmentation. If I ever find any I'm buying it. Even at retard prices. I love fragmentation .22 rounds