Abstract: A smooth bore barrel system utilizes an ammunition round capable to provide the projectile, covered with predetermined usually spiral grooves (44) and lands (42) congruently engaged in the rifled by the same manner inner surface (30A) of the cartridge case (30). When fired the rifled cartridge case serves as a short disposable rifled barrel spinning the projectile. A front short non-rifled part (40B) of the cylindrical portion of the projectile is extended into the smooth bore barrel (20) having sliding fit within. Alternatively, spinning momentum is provided by having the grooves tapering to narrow channels extended through the short cylindrical portion of the projectile forming jets (48), which rotate the projectile by jet propulsion forces. Spinning momentum is gained by two independent approaches which effect could be combined or used separately.

Abstract: A smooth bore barrel system utilizes ammunition round capable to provide the projectile (40) with spinning momentum by two independent approaches which effect could be combined or used separately. The projectile has an elongated cylindrical surface (40C) adjacent to the front ogival shaped surface (40A). A substantial portion of this cylindrical surface is covered with predetermined usually spiral grooves (44) and lends (42) congruently engaged in the rifled by the same manner inner surface (30A) of the cartridge case (30). When fired the rifled cartridge case serves as a short disposable rifled barrel spinning the projectile. A front short non-rifled part (40B) of the cylindrical portion of the projectile is extended into the smooth bore barrel (20) having sliding fit within. Alternatively, spinning momentum is provided by having spiral grooves extended in the front non-grooved portion of the projectile forming jets (48) which rotate the projectile by jet propulsion forces.