A silencer for a firearm in one embodiment includes an outer tube defining a proximal end configured for mounting on a firearm barrel, a distal end, and an internal passageway extending between the ends. A plurality of first baffles is disposed in horizontally stacked relation in the internal passageway between the proximal and distal ends of the tube. The first baffles each comprises an annular mounting sleeve and a cone projecting axially rearward from the sleeve towards the proximal end of the tube. The cone defines an oblong obliquely angled central opening concentrically aligned the bore of a firearm barrel for receiving a projectile therethrough. Gas expansion chambers are formed between the first baffles. The cone may have an asymmetrically skewed shape for cross-jetting. An anti-rotation feature is provided which prevents the silencer assembly from loosening when the silencer is coupled to the firearm barrel.