Base metals constitute one of the fundamental pillars of industrial economies and play a strategic role in connecting mining activities, energy supply, transportation systems, machinery production, construction, infrastructure development, and downstream manufacturing industries. Despite Iran’s considerable mineral reserves and production capacities in sectors such as steel, copper, and aluminum, the extent to which the country has succeeded in developing a deep and integrated production chain remains an important policy and research question. This study aimed to comparatively examine the production chain of base metals in Iran, China, and the United States using the Average Propagation Length (APL) index within the framework of input–output analysis. The research adopted a descriptive–analytical approach based on domesticated input–output tables. Backward and forward APL indices were calculated in both raw and normalized forms for selected years in the three countries. The findings indicated that although the base metals sector in Iran occupied a relatively important position compared with the national economic average, it still lagged behind China and especially the United States in terms of production-chain depth, structural complexity, and intersectoral integration. The results suggest that improving Iran’s industrial position requires strengthening backward and forward linkages, expanding downstream industries, reducing raw and semi-processed material exports, and shifting industrial policy from resource-based production toward integrated and value-added production chains.