High spin projectile apparatus for smooth bore barrels

#The present invention relates to accurate, extended-range firearms ammunition for use with smooth bore pistols, rifles, shotguns, muzzle loading guns, and the like.

#Whether of small or large caliber, the rifled barrel has dominated projectile weapons as a means of introducing flight-stabilizing spin to the projectile. Rifled barrel twist rates from 1:36 or less to 1:7 or more produce rotational rates of from 30,000 to 300,000 RPM or more, which is sufficient to stabilize projectiles with length to diameter ratios of up to 5:1 or more. At any caliber or ratio, such projectiles from un-rifled barrels readily tumble, which greatly reduces accuracy and range.

#The use of single-projectile bullets or slugs with smooth-bore shotguns has a long history of innovation to increase range and accuracy. U.S. Pat. No. 3,726,231 discloses a waisted slug known as the BRI slug or bullet. Such waisted slugs grew to prominence in the 1970's and 1980's. The hollowed aft portion of the Foster slug improves accuracy by placing more mass in the front of the projectile, therefore reducing to some degree the tumble of solid slugs. The Brenneke slug achieves a similar result by retaining connection with the lower density wadding during flight, thereby increasing range and accuracy in smooth bore guns.

#The present invention can be even better understood with reference to the appended drawings that are intended to illustrate, not limit, the present invention.

#FIG. 1 is a graph showing a comparison of drag characteristics for various nose shapes in the transonic to low Mach regions. The rankings shown in FIG. 1, used to characterize the shapes, are: superior (1), good (2), fair (3), and inferior (4).

#FIG. 2 is a schematic diagram showing the orientation of nozzles for directing combustion gases into impulse turbine rotor elements or blades, in a projectile apparatus according to various embodiments of the present invention.

#In one or more embodiments of the present invention, an element or feature of the projectile apparatus, configured to convert blast pressure from burring propellant to effect projectile spin, comprises one or more turbine structures. If more than one turbine structure is provided, the turbine structures can each be the same as or different from at least one other. These structures can be implemented as part of the projectile, part of a sabot, part of a wadding, part of an intermediary component, the entirely of any such component, or a combination thereof. For example, the projectile apparatus can have a wadding that comprises fins, vents, or channels that direct a flow of combustion gases into communication with turbine elements integral with a sabot, causing the sabot and a captured projectile it contains to spin at a high rate, while the wadding, acting as a turbine stator, does not spin substantially relative to the barrel. A system including the projectile apparatus, a projectile, and a smooth bore barrel, is also provided, as is a method of using the system.

#According to various embodiments of the present invention, a sabot is provided that comprises fins, vents, or channels that direct a flow of combustion gases into communication with turbine elements that are part of the projectile, wherein the sabot is substantially not in rotation relative to the barrel while the projectile spins inside the sabot. In yet other embodiments of the present invention, a wadding is included that can regulate, direct, control, or a combination thereof, the flow of combustion gases into turbine elements of the projectile, causing the projectile to spin at a high rate of speed while the wadding is substantially prevented from rotation relative to the barrel. The wadding can be prevented from spinning, for example, due to friction. In still other embodiments of the present invention, one or more intermediary elements or components are included that can regulate, direct, control, or a combination thereof, the flow of combustion gases into turbine elements of the projectile, causing the projectile to spin at a high rate of speed while the wadding is substantially prevented from rotation relative to the barrel. The intermediary elements or components can be prevented from spinning, for example, due to friction. In other embodiments, the intermediary components may mechanically link two or more of the projectile, the sabot or the wadding. A system comprising such a sabot, a projectile, and a smooth bore barrel, as well as a method using the system, are also provided.

#In each of the various embodiments described above, the projectile, sabot, intermediary components, or wadding can have features that reduce friction against the barrel. It is to be understood that such embodiments do not preclude either the projectile, the sabot, the intermediary components, or a combination thereof, from being acted-upon directly by combustion gases, without regulation, control, or direction from another device.