Quite enough to comfortably shoot without hearing protection from my rifles with long barrels. They make more noise than a .22 caliber pellet rifle, though. They still have a sharp rap from a handgun that makes me wich for ear plugs when I shoot them.
Same is true for the Super Colibri primer driven ones, but they are even more quite than the CB shorts.
since they will handcycle from the mag. With a 20" barrel, I used to use them to take squirrels, starlings, etc, in our little town of 7000 people, in antigun ILL. Just stayed out of sight in the garage, dropped the critters out of the open overhead door.