- "Cylindrical barrel-mounted sound suppressor; Reduces speed of propellant gasses, resulting in an overall reduction of volume for each shot fired."
- ―Armat A9 Sound Suppressor description (from Aliens: Colonial Marines - Arsenal Upgrades)
The A9 Sound Suppressor reduce the noise signature of each shot fired by allowing the rapidly expanding gases from the firing of the cartridge to be decelerated and cooled through a series of hollow chambers. The trapped gas exits the A9 over a longer period of time and at a greatly reduced velocity, producing less noise signature. The A9 also reduces or virtually eliminates the amount of visible muzzle flash generated by firing the weapon as the flash is both contained in the A9 and unburned powder is arrested by the A9, which would normally burn in the air, adding to the flash. The A9 also reduces recoil by the slowing of propellant gasses which can contribute 30-50% of recoil velocity. The weight of suppressor and the location of that additional weight at the muzzle reduce recoil through basic mass as well as muzzle flip due to the location of this mass.