Abstract: A venturi section or cone for a lightweight firearm such as a recoilles gun which is subjected to high transient pressures and temperatures on firing is formed from a resin impregnated multi-filament fiber material. The material in the form of an elongated tow is wound on a mandrel, cured, and then removed from the mandrel for subsequent operations such as machining or assembly. During manufacture, a hot gas erosion preventing layer is first formed on the mandrel and a plurality of layers of two are helically wound thereon at a helix angle selected to provide adequate axial and hoop strengths for resisting axial thrust and hoop loads produced on firing. Lightweight recoilless guns using such venturi cones are lighter and cheaper to fabricate than conventional guns and will fire more rounds before excessive erosion causes them to be unusable.

Abstract: A barrel section for a lightweight firearm such as a recoilless gun which is subjected to extremely high transient internal pressures and temperatures on firing is formed from an epoxy-resin impregnated carbon fibre material. The material, in the form of an elongated tow is wound on a mandrel, cured and then removed from the mandrel for subsequent operations such as machining and assembly. During manufacture, a gas-erosion preventing layer is formed on the mandrel and a plurality of layers of tow are helically-wound thereon at a helix angle .theta.=tan.sup.-1 (.sigma..sub.axial /.sigma..sub.hoop) where .sigma..sub.axial and .sigma..sub.hoop are the axial and hoop stresses produced in the barrel section by axial and hoop loads respectively. Lightweight recoilless guns using barrels in accordance with the invention are lighter and less costly to fabricate than conventional guns and are capable of firing upwards of 30 rounds before excessive erosion causes the firearm to be unusable.

Abstract: A conversion assembly for converting a practice warhead (10) into an armour penetrating warhead (30) is disclosed. The practice warhead (10) is the type having a plastic shell (11) with sockets (20,22) at both ends for receiving a metal ballast, such as a steel rod (24). The conversion assembly consists of a penetrator rod (32) of heavy metal with an outside diameter (D.sub.R) substantially less than the inside diameter of the sockets (20,22) in the shell (11) and two adaptor cups (34) of elastomeric material that are stretched over the ends of the penetrator rod (32) and then fitted into the sockets in the shell. The adaptor cups (34) each have, in the relaxed state, a substantially uniform peripheral wall thickness, an inner diameter slightly less than the outside diameter (D.sub.R) of the penetrator rod (32) and an outside diameter slightly less than the inside diameter of the sockets (20,22) in the shell (11).

Abstract: A tubular structural element comprises a tubular body made of a fiber reinforced composite material having reinforcing fibers embedded in a matrix. The fibers are one of carbon, berylium, boron, glass, metallic or non-metallic, or a hybridized combination of the same. The tubular body has projections interiorly thereof which are integral therewith, and are of the same or another fiber reinforced composite material. The reinforcing fibers in the body are oriented in mutual stress transmitting relation, preferably circumferentially in the tubular body, and longitudinally in the interior projections. In making the tubular structural element, the fiber reinforced composite is introduced into each channel formed in a mandrel. The channels extend generally longitudinally of the mandrel, and optionally may also be spirally or helically oriented. Additional composite material is then overlaid generally circumferentially on the mandrel, to a desired thickness.