Barrels for electromagnetic guns

A gun barrel for firing a projectile and particularly a rail gun barrel that comprises a pair of spaced apart rails and a pair of spaced apart insulators, which separate the rails, and together define a composite bore, all disposed centrally within an outer rigid tube. A prestressed filament-wound polymeric resin shell immediately surrounds and applies compressive stress to this composite, bore-defining structure. A pressure medium, positioned between the shell and the interior surface of the outer tube, is operative to apply compressive stress to the shell at least at locations generally radially outward of the rails. The compressive stresses applied by the combination of the prestressed shell and the pressure medium are additive and effectively preload the rails and the composite bore structure to resist overall forces encountered during projectile firing which, in a rail gun, include asymmetric loads upon the rails from electromagnetic repulsion forces and also axisymmetric bursting forces.