The linked Forgotten Weapons goes in to detail about the rubber seals, which the projectile pierces through when the weapon is fired.
The rubber partially reseals, but after a dozen shots or so the weapon degrades to the performance of a normal silenced pistol.
This probably explains the discrepancy. It is indeed very quiet, and my interpretation of the quote is wrong.
The linked Forgotten Weapons goes in to detail about the rubber seals, which the projectile pierces through when the weapon is fired.
The rubber partially reseals, but after a dozen shots or so the weapon degrades to the performance of a normal silenced pistol.
This probably explains the discrepancy. It is indeed very quiet, and my interpretation of the quote is wrong.