High spin projectile apparatus comprising components made by additive manufacture

A method of making a projectile apparatus, the projectile apparatus comprising a propellant and a projectile, the projectile apparatus and elements thereof being configured to spin when fired from a smooth bore barrel, the propellant comprising a combustible material that produces exhaust gases when burned, the projectile apparatus being configured to direct exhaust gases from the propellant away from the projectile as the propellant is burned, and the projectile comprising one or more elements or features for converting gas pressure or velocity from the propellant, as the propellant is burned, to a high rate of projectile spin within a smooth bore barrel, wherein the high rate of projectile spin is greater than 30,000 rotations per minute upon exiting the barrel, wherein the method comprises making the one or more elements or features by additive manufacture, wherein the one or more elements or features comprise a turbine element, and the turbine element is one of an impulse turbine element, a reactive turbine element, a centripetal turbine element, a Tesla turbine element, a magnetohydrodynamic turbine element, a radial turbine, or a combination thereof, and the one or more elements or features are configured to regulate, control, and direct gases produced by the propellant, as the propellant is burned, into the turbine element, and wherein the projectile comprises one or more channels or ducts that begin at, or near, the rear of the projectile and extend to, or near, the front of the projectile, the one or more channels or ducts are configured to convey exhaust gas from the propellant as the propellant is burned, to one or more rotational nozzles or jets configured to direct exhaust to a smooth bore barrel ahead of the projectile.