A novel atmospheric swirl stabilized dump combustor to facilitate instability investigations and the acquisition of validation and boundary condition data for large eddy simulation has been investigated when artificially perturbed. Combustor features include the capabilities of imposing pressure perturbations upon the premixed flow, preheating the reactant mixture up to 400 degrees C, and introducing dilution air into the chamber. The combustor design is presented in detail. A fully premixed methane/air mixture of equivalence ratio 0.8 and mass flow of 20mgs(-1) perturbed at 100Hz, 200Hz, and 400Hz was investigated in significant detail and the analysis completed. A full description of the high speed phase locked CH chemiluminescence and stereo particle imaging velocimetry used to characterize the unsteady reacting fields, flow fields, and vortex breakdown is given. The ensemble average results presented reveal changes in flame structure with frequency. These were attributed to the upstream movement of the toroidal vortex ring within the internal recirculation zone.