Solid-fuel ramjet ammunition

A ramjet projectile comprising: an outer assembly that is tubular and comprises first, second and third portions; solid ramjet fuel attached to and disposed inside the first portion of the outer assembly; an inner assembly disposed inside the outer assembly and comprising a first portion threadably coupled to the second portion of the outer assembly and a second portion surrounded by the third portion of the outer assembly to form an annular air passageway having an air inlet. The first portion of the inner assembly comprising a plurality of openings spatially distributed about a circumference. The inner assembly is rotatable relative to the outer assembly between first and second locations displaced by a distance from each other during travel along the gun barrel. The openings are not in flow communication with the annular air passageway when the inner assembly is at the first location and are in flow communication with the annular air passageway when the inner assembly is at the second location. Preferably the solid ramjet fuel comprises boron and a binder.