TECHNICAL FIELD

This invention relates to a cylindrical bullet projectile intended for firing from smooth-bore shotguns.

BACKGROUND ART

Known cylindrical projectiles for smooth-bore firearms are made as lead casts, usually ribbed, whereas their ribs constitute a whole with the projectile body. Known projectiles are provided with wads of various kinds, located in the rear part of the projectile and used as flight stabilisation means. Also known is a projectile disclosed in the Polish Patent No. PL210994 as a cylindrical projectile with an expansion tip embedded in its head. The projectile has a trailing section with flight stabilisation blades located in grooves on the cylindrical wall of the projectile, and inclined on this wall at an angle equal or greater than 1° from the geometrical axis of the projectile.

DISCLOSURE OF THE INVENTION

A projectile according to this invention, comprising a cylindrical bullet with an expansion tip embedded in its head, as well as a trailing section connected to such bullet, with flight stabilisation blades located in groves on the cylindrical wall of the bullet, and inclined on this wall at an angle equal or greater than 1° from the geometrical axis of the bullet, characterized in that the expansion tip embedded in the bullet head has rims, and the bullet with groves on its cylindrical surface is integral with the trailing section that has at least two flight stabilisation blades located at the circumference of its body, whereas the length of the blades significantly exceeds the height of the trailing section body. The blades extend from the bottom base of the trailing section throughout the entire height of its body and the cylindrical part of the bullet, and their elongated ends are located in groves on the cylindrical wall of the bullet. The blades preferably have arched ends at their tops. Inside the bullet, under the expansion tip, there is a blind hole determining the magnitude of mushrooming, and on the exterior surface of the bullet, there are notches to facilitate mushrooming. The trailing section body has a projection of shape corresponding to the recess in the bottom part of the bullet, whereas the recess and the projection have rims on their circumference, and moreover, the projection of the trailing section has at least one pass-through hole, and there is an empty hole in the base of the trailing section body.

This invention solves the problem of designing a projectile that achieves rotational movement after leaving the smooth-bore barrel of a firearm, resulting in ballistic characteristics of such a firearm approaching these of a rifled firearm.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred example of embodiment of the invention is presented on the drawings, where Fig. 1 presents an external view of the projectile, Fig. 2 - a longitudinal section of the projectile, Fig. 3 - an external view of the grooved, cylindrical bullet, Fig. 4 - a longitudinal section of the cylindrical bullet.

EXAMPLE FOR CARRYING OUT THE INVENTION

The projectile comprises a grooved, cylindrical bullet 1 with an expansion tip 2 with rims embedded in its head. The bullet has a trailing section with at least two flight stabilisation blades 3 located on the circumference of the trailing section. The number of flight stabilisation blades depends on the calibre of the projectile. There are 10 flight stabilisation blades in the preferred example of embodiment. The length of the blades significantly exceeds the height of the trailing section body and the blades extend from the bottom base of the trailing section, throughout the entire height of its body, and their elongated ends are located in groves 4 on the cylindrical wall of the bullet and inclined on this wall at an angle in the range of 8°-12° from the geometrical axis of the bullet. The trailing section body has a projection 10 of shape corresponding to the recess 9 in the bottom part of the bullet. The recess 9 and the projection 10 have rims 11 on their circumference, to allow for joining the bullet and the trailing section during the assembly of the projectile. A hole 6 is located on the longitudinal axis of the trailing section to evacuate air when assembling the bullet 1 with the trailing section 3. Inside the bullet, under the expansion tip 2 with rims located in the head, there is a blind hole 5 determining the magnitude of mushrooming, and on the exterior surface of the bullet, there are notches 7 to facilitate mushrooming. The trailing section blades 3 have arched ends 8 at their tops to reduce air resistance. An empty hole 12 is located in the base of the trailing section body.

The use of the above mentioned trailing section has allowed for achieving both the stabilisation due to the relocation of the centre of gravity, as well as the rotational stabilisation. Such a design makes ballistic characteristics of a smooth-bore firearm approach these of a riffled firearm. Thanks to elastic deformations, the blades are not destroyed while the projectile travels through the barrel, and preserve their function of imparting rotational movement to the projectile by proper flow of air around them after the projectile has left the barrel. Moreover, thanks to minimal friction due to small contact area of blade ridges with barrel surface, the projectile does not wear the barrel bore and, thanks to elastic deformations of the blades, does not decalibrate the barrel choke. The bullet can be made of steel, non-ferrous metals or composite materials. The trailing section with flight stabilisation blades integral with the bullet can be made of polyethylene.

At the moment of primer puncturing, powder ignition occurs, and the resulting powder gas pressure pushes the projectile towards the barrel muzzle with minimal resistance. At that moment, plastic blades of the trailing section get arranged in the barrel bore, and the projectile leaves the barrel. Immediately after leaving the barrel, the blades elastically return to their previous position, and the stream of air flowing around the projectile wall forces it to rotate.

The two kinds of stabilisation acting together on the projectile, due to the relocation of the centre of gravity and due to the rotational movement, maximise target accuracy , which provides good ballistic performance close to that of a riffled firearm.