A stream redirecting device for a sprinkler includes a shell-shaped body having a generally semi-circular shape in plan, with opposite inlet and outlet side edges. The body extends outwardly and upwardly from a base at a lower end and then upwardly and inwardly to a distal, arcuate edge at an upper end. An inside surface of the shell-shaped body is formed with a plurality of grooves between the inlet side edge and the outlet side edge, extending in a generally radial direction with entry ends adjacent the base and exit ends at the distal, arcuate edge. The grooves are formed with circumferential exit angles that vary substantially uniformly in opposite directions from a center one of the plurality of grooves to first and last of the plurality of grooves at the opposite inlet and outlet side edges, respectively.