Sound suppressor for a firearm

A sound suppressor for a firearm, comprising:

• a tubular casing having a proximal end adapted to be attached at the muzzle of a firearm, a distal end comprising an end cap with an exit orifice adapted to permit the passage of a projectile;
• a core structure situated in the interior of said tubular casing and defining a at least one flow disruptor adapted to disrupt flow of propellant gases leaving said muzzle, said core structure furthermore defining a projectile passageway adapted to be aligned with a bore of said firearm and adapted to permit the passage of a projectile from said muzzle to said exit orifice;
• a plurality of water drainage openings passing through said tubular casing on an underside thereof;
• and
• a shutter comprising a plurality of through-holes, said shutter being slidably mounted on said tubular casing and displaceable from a first position, in which said water drainage openings are aligned with respective through-holes, and a second position, in which said water drainage openings are occluded by said shutter.