The composite solid-propellant deflagration mechanism has been studied experimentally by means of two laboratory burner techniques. The techniques allow experimental parameter variations that are impossible with the propellants (due to their structural pecularities) . The burner is composed of oxidant and fuel granules and has deflagration characteristics that are almost perfectly analogous to those of actual ammonium perchlorate (AP) propellants. The burner involves a bonded, porous AP bed that burns at the surface with emerging fuel gas passed up through the bed; similarly, porous fuel beds are burned with oxidant gas. The close analogy of the loose-granule burner is destroyed (by interstitial flame penetration) at combustion pressures greater than about 50 psia. The porous-plug burner surface emits burning AP crystals at methane throughputs greater than approximately that calculated to yield stoichiometrically correct combustion, thus limiting the analogy as well as suggesting reexamination of the work of others who used such burners to infer the stoichiometry of AP systems. Results from the analog techniques indicate that the propellant deflagration rate is sensitive to fuel-pocket size (which sets the scale of granularity) and details of the fuel combustion process (in addition to over-all energy release).