Abstract: A method for converting mortar shells into shells for use in smooth-bore gun barrels having an interior surface. The mortar shells include a warhead having a front end, a rear end, a tail fin, and a propellant charge. A guide casing is attached to at least the rear end of the warhead. The guide casing includes an outside surface. The guide casing supports at least the rear end of the warhead and is adapted for use with the smooth-bore gun barrel that the converted shells are to be fired from. A bourrelet is attached to the outside surface of the guide casing for sealing between the converted shells and the interior surface of the smooth-bore gun barrel that the converted shells are to be fired from.

Abstract: The invention relates to a drive element (1) for a sub-calibre spinning projectile (2). The drive element (1) comprises an annular sabot member (17) applied on the rear part of the projectile (2) and a guiding sleeve (7) of full-calibre substantially embracing the projectile (2) as well as the sabot member (17). The guiding sleeve (7) is provided with an external driving band (9) made directly in the sleeve material and internal threads coacting with corresponding threads (18) of the sabot member (17). The front part of the sabot member is provided with a central, axial hollow (20) for the rear part of the projectile comprising a plurality of axially extending locking pins (22) arranged to engage corresponding recesses (6) made in the outer cylindrical surface of the projectile close to its rear end surface (5) to secure the projectile (2) to the sabot member (17). The guiding sleeve is made of a high-strength material of low density, preferably a glass-fibre reinforced polyamide.