Double-base propellants have nitrocellulose and nitroglycerin as their explosive ingredients and diphenylamine (DPA) as the stabilizer. Although ammunition stockpile must be evaluated for safe and stable management, the ammunition stockpile reliability program (ASRP) monitoring performance, reliability, and safety characteristics of ammunition barely applies to small-caliber ammunition. In this study, we calculated the shelf-life of a small-caliber ammunition stockpile by analyzing loss of stabilizing agents in double-based propellants stored at 60–80 ℃ using high-performance liquid chromatography (HPLC). Using the Arrhenius model, the shelf-life of double-based propellants was calculated to be 58.25–83.31 years. However, the shelf-life of propellants is expected to be longer because of first and second derivatives such as N-Nitroso DPA(N-NO DPA) on the decomposition pathway of DPA.