The criminal use of explosives has increased in recent years. Political instability and the wide spread access to the internet, filled with "homemade recipes," are two conjectures for the increase. C-4 is a plastic bonded explosive (PBX) comprised of 91% of the high explosive RDX, 1.6% processing oils, 5.3% plasticizer, and 2.1% polyisobutylene (PIB). C-4 is most commonly used for military purposes, but also has found use in commercial industry as well. Current methods for the forensic analysis of C-4 are limited to identification of the explosive; however, recent publications have suggested the plausibility of discrimination between C-4 samples based upon the processing oils and stable isotope ratios. This research focuses on the discrimination of C-4 samples based on ratios of RDX to HMX, a common impurity resulting from RDX synthesis. The relative amounts of HMX are a function of the RDX synthetic route and conditions. RDX was extracted from different C-4 samples and was analyzed by ESI-MS-SIM as the chloride adduct, EI-GC-MS-SIM, and NICI-GC-MS. Ratios (RDX/HMX) were calculated for each method. An analysis of variance (ANOVA) followed by a Tukey HSD allowed for an overall discriminating power to be assessed for each analytical method. The C-4 processing oils were also extracted, and analyzed by direct exposure probe mass spectrometry (DEP-MS) with electron ionization, a technique that requires less than two minutes for analysis. The overall discriminating power of the processing oils was calculated by conducting a series of t tests. Lastly, a set of heterogeneous commercial blasting agents were analyzed by laser induced breakdown spectroscopy (LIBS). The data was analyzed by principal components analysis (PCA), and the possibility of creating a searchable library was explored.