Abstract: A shot cup retardation device including circumferentially spaced and radially protruding ridges, pins, studs, or set screws; or an applied grit around an inner circumference of a barrel; or a plurality of continuous circumferential ribs arranged axially spaced apart within the barrel, all for retarding the velocity of a shot cup so as to inhibit interference between shot and cup downstream of the shotgun muzzle. Additionally, the invention provides that a shot cup retardation device and a downstream choke or pattern conditioner can be utilized in combination to produce a fine tuned and selective pattern without the random influence of shot cup and shot interference.