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job at hand). Conversely, several factors do have a significant influence upon effective plume penetration depth; these include but are not necessarily limited to:

Flash hole diameter (a smaller flash hole might produce a more intense plume jet that could penetrate slightly farther into propellant column but at the same time it could deliver less of the still reacting gases and particulates through the flash hole so that total primary ignition volume could be either equal, greater, or lesser)
Granule size (larger granules tend to create larger void spaces so that permeability tends to be greater and so that compression of charge mass will not as readily close permeable paths; hence, larger granules might provide primary ignition to a slightly greater depth, compared to smaller granules)
Granule configuration (compared to the, relatively weak, flake or significantly flattened spherical granule types, the relatively tougher tubular and spherical granules might be expected to support permeable pathways against a greater compressive force)
Granule deterrent coating type and degree (certain types of deterrent coatings differentially adsorbed into granule surface – with greatest concentration at surface – and higher concentrations of any deterrent coating require increased granule surface heating to achieve ignition temperature, hence effective ignition depth will be less with granules that are more heavily deterred)