Abstract: A method of producing plastic-based casings including preformed metal fragments for ordnance articles, such as hand grenades, weapon-launched grenades or the like, by rotational molding in a shell-mold; a pulverulent thermoplastic polymer material, such as polyethylene, and steel fragments or particles are introduced into the cold shell mold, optionally in the form of a pre-compact; the closed mold is rotated slowly, i.e. at a speed where the polymer and metal constituents tend to tumble about the inner mold surface and are not held substantially thereon by centrifugal effects; while continuously rotating the shell mold about two or more axes of rotation, the mold is heated by an externally applied hot fluid such as hot gas.