This study examines the phonetic basis of a contrast described between plain and uvularized vowels in Mawo Qiang (Qiangic, Sino-Tibetan). Building on Evans et al. (2016), it adopts their analytical framework while expanding the empirical basis through newly collected data from nine speakers, analyzed using acoustic measurements and articulatory modelling. The acoustic results show that the contrast is primarily signaled by lowering of F2, whereas changes in F1 and higher-formant measures are weaker and more variable, depending on vowel quality and speaker. The articulatory modelling suggests that vowels described as uvularized often involve posterior displacement of the tongue dorsum, but this is neither the sole nor a uniform strategy. Across vowel pairs, the contrast may also involve tongue lowering, pharyngealization-like configurations, or differences in vowel fronting rather than straightforward retraction. Taken together, these findings indicate that the opposition is acoustically robust but phonetically heterogeneous. Rather than reflecting a single invariant uvular gesture, the data indicate multiple articulatory strategies converging on a similar acoustic effect, particularly F2 lowering. Accordingly, if the contrast is phonologically structured as proposed in previous work, its phonetic realization may be better understood in terms of relative fronting versus retraction rather than uniform uvular secondary articulation. These results contribute to discussions of secondary vowel articulations in Qiangic languages. They also highlight the importance of distinguishing between phonological categories and their phonetic realization, and the value of detailed instrumental investigation in refining the articulatory characterization of typologically rare contrasts.