Abstract: A wobbling irrigation sprinkler head is provided for use on a self-propelled mechanically moving irrigation system, such as a center pivot field irrigation system having the wobbling sprinkler head facing downward from the water supply conduit. The sprinkler head has a base for attaching to a pipe or to the central water supply conduit which base has nozzle mounted therein for directing water against a wobbling water deflecting head which is movably attached to the base and supports a deflector pad. The deflector pad has a deflection surface of predetermined shape with water deflecting grooves formed therein for rotating and wobbling the water deflecting head. The deflecting head has a loose fitting sleeve portion surrounding a support arm on the base and the base has a removable nozzle insert holder having a flange to loosely hold the deflecting head thereto.