Experimental conditions necessary for self-pulsing to occur in a He-Ne ring laser are reported. These results are compared with predictions that are based upon theoretical models that have been presented in the literature. Good qualitative agreement is found in that theory and experiment both show that self-pulsing will only occur over a range of excitation. Quantitative results differed enough to indicate that additional refinement is needed even though the models have identified many of the important parameters involved.