In one example, a firearm attachment includes a base adapted to be coupled to a firearm. The firearm attachment also includes a plurality of substantially longitudinal tines extending forwardly from the base and arranged circumferentially around a central axis of the attachment. The firearm attachment also includes at least one bore substantially concentric with the central axis. The firearm attachment also includes three longitudinal slots defined by sidewalls of adjacent ones of the tines and adapted to pass combustion gases from the bore. The sidewalls extend from the bore to an outer circumfery of the attachment. Sidewalls of adjacent tines lie in respective planes that intersect at an angle in a range of approximately 9 degrees to approximately 12 degrees. Other implementations and related methods are also provided.