We present 430-M Hz Arecibo single pulse polarization measurements for PSR 2303+30. Single pulses typically consist of one or two subpulses. Each subpulse is associated with circular polarization which reverses sense near the subpulse peak and with its own swing of the position angle which does not coincide with the average position-angle curve. We attempt to explain these complicated characteristics within the framework of a coherent curvature radiation model of pulsar emission.