Monolithic bullet projectile for rifle firearms and method of making same

Abstract

The invention comprises a monolithic bullet projectile for rifle firearms (FIG. 1), having cylindrical profile of front guiding section (CP) of a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the firearm barrel, with specific short head (CG) of half-circle or cone shape, and a method of making same. It is characterized in that the centre of gravity (SC) is situated in the front, cylindrical guiding section of the bullet, and the back trailing section (CW), situated behind the centre of gravity (SC) of the whole bullet, has radial profiling comprising the relieving grooves (RO) of a diameter lower than a diameter of lands (øP) of the rifled bore of the firearm barrel and the trailing rings (PW) of a diameter which is equal to or lower than a diameter of the rifles (øB) of the rifled bore of the firearm barrel, situated in the following order: trailing ring-relieving groove-trailing ring or multiplication of that configuration, so that the total number of the trailing rings (PW) of the bullet is always twice as high as the number of relieving grooves (RO) of the bullet. A method of making the bullet according to the invention is characterized in that the guiding section of the bullet (CP) is calibrated independently up to a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the barrel, and the radial profiling of the trailing section of the bullet (CW), comprising the relieving grooves (RO) and trailing rings (PW), is made in a single technological operation, applying for the making of trailing rings (PW) the effect of upsetting of the homogeneous material of the bullet along the edge of the radial relieving groove (RO) while the trailing section of the bullet (CW) is calibrated independently up to a diameter which is lower than or equal to a diameter of the rifles (øB) of the rifled bore of the barrel.

Description

TECHNICAL FIELD

The invention relates to a monolithic bullet projectile for rifle firearms and to a simple method of making same.

BACKGROUND ART

Heavy, blunt head projectiles made from copper or brass, of stable mass and shape known as full monolithic projectiles (Solid or Monobloc type) are commonly used, especially in huntsman's practice (Manfred R. Rosenberger “Huntsman's ammunition; Structure; Behavior inside the target; Application” Bellona Ed., Warsaw 2009, pp. 198-206). Such projectiles maintain stable ballistic flight trajectory due to gyroscopic stabilization.

BRIEF SUMMARY OF THE INVENTION

The invention relates to a monolithic bullet projectile for rifle firearms, having cylindrical profile of front guiding section (CP) with specific short head (CG) of half-circle or cone shape, and the back trailing section (CW), situated behind the centre of gravity (SC) of the whole bullet, having radial profiling comprising the relieving grooves (RO) and the trailing rings (PW), situated in the following order: trailing ring-relieving groove-trailing ring or multiplication of that configuration.

The invention relates further to a method of making the bullet according to the invention wherein the guiding section of the bullet (CP) is calibrated independently up to a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the barrel, and the radial profiling of the trailing section of the bullet (CW), comprising the relieving grooves (RO) and trailing rings (PW), is made in a single technological operation, applying for the making of trailing rings (PW) the effect of upsetting of the homogeneous material of the bullet along the edge of the radial relieving groove (RO) while the trailing section of the bullet (CW) is calibrated independently up to a diameter which is lower than or equal to a diameter of the rifles (øB) of the rifled bore of the barrel.

According to the invention, independent calibration of a diameter of lands (øP) and of a diameter of the rifles (øB) allows for individual fitting of the external dimensions of the bullet to any barrel of the rifle firearm, even if the wear of the rifle is significant which is crucial in the process of extending the lifetime of the firearm.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention is described in detail in reference to the accompanying drawings, in which:

FIG. 1 presents a half-section of the bullet projectile;

FIG. 2 presents a cross-section of the typical rifled barrel bore of a firearm;

FIG. 3 presents a scheme of the operation of cutting the starting material for the bullet and of shaping the bullet head—front view (left) and side view (right);

FIG. 3a presents the start of the operation of cutting the weighed billet;

FIG. 3b presents the end of the operation of cutting the weighed billet;

FIG. 4 presents scheme of the operation of calibrating the guiding section of the bullet, including finishing the bottom surface;

FIG. 5 presents scheme of the operation of cutting the relieving grooves including simultaneous profiling of the guiding rings of the bullet—front view (left) and side view (right);

FIG. 5a presents the start of the operation of cutting the relieving grooves;

FIG. 5b presents the end of the operation of cutting the relieving grooves;

FIG. 6 presents the scheme of the operation of calibrating the trailing section of the bullet.

DISCLOSURE OF THE INVENTION

According to the invention the bullet projectile made fully of copper or copper alloys, as shown in a half-section in FIG. 1, has typical cylindrical profile of guiding section (CP) with very short head (CG) of half-circle or cone shape. Trailing section of the bullet (CW), situated in its back behind its centre of gravity (SC), has radial profiling comprising the relieving grooves (RO) of a diameter which is lower than a diameter of the lands (øP) of the rifled barrel bore and the trailing rings (PW) of a diameter which is lower than or equal to a diameter of the rifles (øB) of the rifled barrel bore. Short bottom section of the bullet (CD) is terminated with a truncated cone or with a flat.

A cross-section of typical rifled barrel bore of a firearm is shown in FIG. 2.

Relieving grooves (RO) diminish the radial stiffness of bullet solid body, resulting in reduction of force needed to overcome the resistance of rifled barrel bore to the bullet driving along.

Trailing rings (PW) which are responsible for providing gyroscopic stabilization effect to the bullet, increase tightness between bullet body and rifled barrel bore, resulting in reduction of working pressure losses of gunpowder gases in the back space of the barrel.

Situation of trailing rings (PW) in the back section of the bullet, behind the centre of gravity (SC), results in improvement of ballistic characteristics of the bullet flight after the bullet leaves the barrel bore, through providing additional fin stabilization due to increasing the resistance to air flowing around the extended back of the bullet, as disclosed in PI Patent PL 211026 B1 published on 30 Mar. 2012 WUP March 2012.

Guiding section of the bullet (CP) comprises a smooth cylindrical area of a diameter equal to or lower than a diameter of the lands (øP) of the rifled barrel bore, providing a slide fit of that section of the bullet in the barrel bore which improves characteristics of interior ballistics through diminishing the resistance related to surface friction during driving of the bullet along the barrel bore.

Short head section of the bullet (CG) which can comprise a spherical cap, a hemisphere, a truncated hemisphere, a cone, a truncated cone or a flat, ensures a stable flight of the bullet when it flies through light hurdles (shrubs, grass) due to edge stabilization which is created during flight because of the asymmetrical air pressure growing on the head of bullet. This is crucial when the bullet is used in huntsman's firearms. In the same time the sharp edge which is formed on the bullet in the spot where the bullet head (CG) continues into cylindrical guiding section of the bullet (CP) ensures ideally cut shape of the bullet hole in the target. This is crucial when the bullet is used in sport firearms.

Design of the bullet projectile of the invention improves (as compared to the state of the art) interior ballistics characteristics (inside the barrel bore), exterior ballistics characteristics (in the air) and final ballistics characteristics (in the target) and ensures full stabilization of the bullet flight path through combining the effects of gyroscopic stabilization, fin stabilization and edge stabilization, which cannot be achieved using the known so far designs of bullet projectiles for rifle firearms.

According to the invention it is possible to make a monolithic bullet projectile for rifle firearms in economical way (wasteless) and simple way (without applying complex machinery and devices).

According to the invention, a method of making a monolithic bullet projectile is characterized by simplicity of technological process which can be implemented in workshop conditions, even without mechanical drive. This is crucial in the process of ammunition reloading in the household or in the field for hunting or sport purpose.

According to the invention the following four technological operations are suitable for making a monolithic bullet projectile of any caliber and weight: cutting the weighed billet, calibrating the guiding section of the bullet, cutting the relieving grooves, calibrating the trailing section of the bullet.

Operation I of Cutting the Weighed Billet

Scheme of the operation of cutting the starting material for the bullet and of shaping the bullet head is shown in FIG. 3. Front view of cutting and shaping operation is show on the left side of FIG. 3. Side view of cutting and shaping operation is shown on the right side of FIG. 3.

Cutting (which includes shaping of bullet head) of the starting material (1), supplied in the form of either a wire or a rod, of a diameter which is equal to or higher than a diameter of lands of final barrel bore of the rifle firearm, to obtain billets (2) corresponding to the required bullet weight, is performed through combining the rotary motion (ω) of starting material and radial motion (r) of the adequately shaped cutting roll (3), against the pair of supporting rolls (4).

The start of cutting operation is shown in FIG. 3a.

The end of cutting operation is shown in FIG. 3b.

Operation II of Calibrating the Guiding Section of the Bullet.

Scheme of the operation of calibrating the guiding section of the bullet, including finishing the bottom surface, is shown in FIG. 4.

Calibrating the guiding section of the bullet (2) up to a diameter which is equal to or lower than a diameter of the lands (øP) of the final barrel bore of the firearm is made by redrawing (s) with a punch (5) in a die (6) having a cone-shaped input hole and a cylindrical calibrating hole (øP). Pressing the head of the punch (5) against the bottom section of the bullet results in simultaneous finishing of the surface of the bullet's bottom (back flat).

Operation III of Cutting the Relieving Grooves.

Scheme of the operation of cutting the relieving grooves including simultaneous profiling of the guiding rings of the bullet is shown in FIG. 5. Front view of operation of cutting the relieving grooves is shown on the left side of FIG. 5. Side view of operation of cutting the relieving grooves is shown on the right side of FIG. 5.

Cutting the relieving grooves on the guiding section of the bullet, including simultaneous profiling of the guiding rings (through upsetting of the bullet material along both edges of the radial groove which is being cut off), is made by combining the rotary motion (ω) of the billet (2) and radial motion (r) of the cutting roll or set of cutting rolls (7) against a pair of cylindrical supporting rolls (8). Cutting the relieving grooves should be done such that the depth of the cuts should go deeper than the diameter of the lands of the final barrel bore of the firearm, and the height of the upsetting of the guiding rings should be higher than the depth of the rifles of the final barrel bore of the firearm.

The start of cutting operation is show in FIG. 5a.

The end of cutting operation is shown in FIG. 5b.

Operation IV of Calibrating the Trailing Section of the Bullet.

Scheme of the operation of calibrating the trailing section of the bullet is shown in FIG. 6.

Calibrating the trailing section of the bullet (2) formed of series of trailing rings, up to a diameter which is equal to or lower than a diameter of the rifles (øB) of the final barrel bore is made by one step redrawing (s) using a punch (9) in a die (10) with an input cone-shaped hole and a cylindrical calibrating hole (øB).

According to the invention, independent calibration of a diameter of lands (øP) and of a diameter of the rifles (øB) allows for individual fitting of the external dimensions of the bullet to any barrel of the rifle firearm, even if the wear of the rifle is significant which is crucial in the process of extending the lifetime of the firearm.

Claims

1. A monolithic bullet projectile for rifle firearms, having cylindrical profile of front guiding section (CP) of a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the firearm barrel, with specific short head (CG) shaped as a spherical cap, a hemisphere, a truncated hemisphere, a cone, a truncated cone or a flat, wherein the centre of gravity (SC) of the bullet is situated in the cylindrical front guiding section of the bullet.

2. A monolithic bullet projectile according to claim 1, wherein the back trailing section (CW), situated behind the centre of gravity (SC) of the whole bullet, has radial profiling comprising the relieving grooves (RO) of a diameter lower than a diameter of lands (øP) of the rifled bore of the firearm barrel and the trailing rings (PW) of a diameter which is equal to or lower than a diameter of the rifles (øB) of the rifled bore of the firearm barrel, situated in the following order: trailing ring-relieving groove-trailing ring or multiplication of that configuration, so that the total number of the trailing rings (PW) of the bullet is always twice as high as the number of relieving grooves (RO) of the bullet.

3. A method of making a monolithic bullet projectile for rifled firearms, made of copper or copper alloys, wherein radial profiling of the trailing section of the bullet (CW) comprising the relieving grooves (RO) and trailing rings (PW), situated in the following order: trailing ring-relieving groove-trailing ring or multiplication of that configuration, is made in a single technological operation, applying for the making of trailing rings the effect of upsetting of the homogeneous material of the bullet (2) along the edge of the radial relieving groove, using a cutting roll or a set of cutting rolls (7) acting together with cylindrical rolls (8) supporting the bullet material.

4. A method according to claim 3, wherein the guiding section of the bullet (CP) is calibrated independently up to a diameter which is lower than or equal to a diameter of lands (øP) of the rifled bore of the barrel, and the trailing section of the bullet (CW) is calibrated independently up to a diameter which is lower than or equal to a diameter of rifles (øB) of the rifled bore of the barrel.