Modern International Relations theories of conflict largely relies on rationality-based arguments to explain the variance in interstate armed conflict. In this paper, I introduce a stricter logic, that of a global arms production constraint, to explain why conflicts between states of disparate military strengths are more likely to engage in militarized conflict in the post-World War II era. I argue that due to the increased complexity and specialization of arms production, the manufacture and supply of modern arms globally is highly concentrated and constrained. My results show that in the post-WWII period, states of disparate military strengths are 58.4\% more likely to engage in militarized conflict. This paper makes a methodological contribution by introducing a new measurement of military strength using a two-step Principal Component Analysis – Manhattan Distance (PCA-MD) technique and k-Means Clustering on comprehensive arsenal data from 1970 – 2014 to better reflect the effectiveness of combined arms capabilities in modern warfare.