FR2774162A1 - Projectile with polygonal conical guide for firearm with rifled barrel - Google Patents

Abstract

The projectile, comprising a rear guide (3) and a core (4) assembled with a positive stress, has a tapering cavity (9) in the guide to receive the core. The guide's outer wall is smooth, while the inner wall of the cavity has three more or less flat faces (20) extending perpendicular to radial lines drawn from the cavity's lengthwise median axis. The flat faces form a means of absorbing material of the guide as it is deformed by the barrel rifling when fired.

Description

 The invention relates to a projectile with a polygonal conical guide, and to a munition for a rifle with a rifled barrel, comprising such a projectile.

 The general technical field of the invention is therefore that of ammunition, and more particularly of the mounting of cores in projectile guides.

 After the start of a shot, the projectile is rotated, under the effect of the barrel scratches.

 This allows the projectile to maintain a more regular trajectory and increase the range of the shot.

 But the projectile is then brutally deformed under the effect of scratches. This deformation generates stresses detrimental to the accuracy of the shot and the longevity of the barrel of the weapon.

 Various projectiles for rifled barrel firearms are known.

 Thus, document EP-B-0.112.216 describes a composite projectile with a perforating core, for such a weapon.

 This projectile comprises means for securing by conical fitting, to ensure a self-tightening effect between a central core and a rear or guide body, less hard than the core.

 The latter has on the outside, hollows and bulges, connecting progressively.

 Although particularly effective in many uses, such a projectile is not completely satisfactory in others.

In general, this projectile does not allow enough
- avoid braking in certain materials from target environments; In particular, when the target medium to be crossed by the projectile is a fibrous material, the fibers tend to wrap around the recesses and bulge, by braking it, or even by stopping it.

- to obtain a good external ballistics, or a good coefficient of penetration in the air, ensuring an optimal remaining energy for long distance shots and
- to obtain a gradual scratching, by limiting alterations to the barrel.

 Let us also cite the document FR-A-1,240,110 which describes a projectile such as a bullet or shell, comprising an external envelope with an internal cylindrical housing in which is fitted from the rear, an internal element such as a tracing bucket or a perforating core.

 Streak-shaped depressions are provided between the outer shell and the inner member, to the rear end of the shell, parallel or inclined to the axis of the projectile.

 These streaks are intended to avoid play on the fitting, as well as annoying deformations during mounting and taking scratches.

 To enclose the inner element, the back of the envelope is folded towards the center. And an external groove on the envelope, encloses the inner element.

 Therefore, this document aims to minimize the fitting constraints, unlike the document EP-B-0.112.216 which seeks an assembly based on a necessarily positive and controlled constraint.

 Furthermore, document FR-A-1,240,110 describes a projectile with an envelope, and not with a guide.

 However, a thin envelope, for example between 0.2 and 0.5 mm thick, and provided with ridges, cannot ensure good training of the central core when taking scratches, and accelerating in rotation suffered at the start of the coup.

 The teaching of this document cannot therefore be effectively put into practice, in particular for a penetrating projectile.

 While the groove brakes it when fired, if it is out of the cartridge case.

 The object of the invention is to overcome these drawbacks, among other things.

 It offers ammunition, the projectile of which is capable of perforating materials, in particular fibrous materials, while limiting its friction inside the barrel and in the air, in order to allow effective and precise shots at long distance.

 To this end, a first object of the invention is a projectile for a rifle with a barrel barrel.

 This projectile comprises a rear guide and a core, assembled by positive stress fitting.

 The rear guide has an internal housing generally extended along a median longitudinal axis of the projectile, opening towards the front and whose generator is substantially inclined relative to the longitudinal axis, from the inside to the outside from the rear towards the front of the guide.

 The core comprises at the rear, complementary fixing means for fitting in the housing.

 According to the invention, the outer wall of the rear guide is smooth, while the inner wall of the housing has at least three substantially flat faces and extended perpendicular to a radial direction orthogonal to the median longitudinal axis, for example lateral or transverse.

 These faces form means for absorbing masses of material from the guide, deformed under the effect of scratches from the barrel during firing.

 According to one characteristic, the generator is substantially inclined relative to the longitudinal axis, from the inside towards the outside from the rear towards the front of the guide, by an angle of the order of 1 to Sa, and especially around 3.

 For a piercing projectile, the hardness of at least one front part of the core such as point, warhead or bell, is greater than that of the guide.

 According to another characteristic, at least one face is extended substantially from a bottom to a transverse end of the housing forming a stop for the core, so that the corresponding absorption means are through.

 For example, all the faces of the housing are extended substantially from the bottom to the end forming a stop.

 According to yet another characteristic, at least one face is extended so as to define two edges which are substantially parallel in radial projection, to the median longitudinal axis.

 According to one characteristic, the housing comprises at least two contiguous faces.

 For example, all the faces are contiguous so that the section transverse to the median longitudinal axis of the housing is polygonal with four, five, seven or nine sides.

 In one embodiment, the polygonal section of the housing has six faces and its cross section to the longitudinal axis is therefore hexagonal.

 In another embodiment, the polygonal section of the housing has eight faces and its cross section to the longitudinal axis is therefore octagonal.

 According to yet another characteristic, the projectile comprises faces of the absorption means on only part of the periphery of the internal wall of the rear guide, in the form of wide grooves.

 In one embodiment, the projectile has from eight to sixteen faces, and in particular twelve faces, for example regularly distributed along the periphery of the housing.

 In one example, the angular difference in a plane perpendicular to the median longitudinal axis, between two edges spaced by one face and / or between two faces, is substantially equal for at least two spacings and / or faces.

 For example, the edges define substantially identical angular spaces over the entire internal periphery of the housing.

 According to one characteristic, the area of the absorption or vacuum means remaining after assembly of the guide and the core is determined so that they are more extensive than the corresponding male area of the barrel scratches.

 In one embodiment, the ratio between the cross-sectional area in a plane perpendicular to the median longitudinal axis, of the core and of the guide housing is of the order of 0.85 to 0.95, and in particular of the order 0.937.

 For example, the absorption means have an area in section in a plane perpendicular to the median longitudinal axis, of the order of 5% to 10% of the area of the core, and in particular of the order of 6, 6%.

 According to yet another characteristic, the substantially complementary means for fitting the core, comprise a frustoconical finger, provided on the side of its small rear base, with a conical internal cavity, opening at the rear of the finger and intended to receive a heel .

 According to another characteristic, a warhead or front point of the perforating core is of shape substantially symmetrical to that of a frustoconical finger of this core, with respect to a plane perpendicular to the transverse median axis.

 According to one embodiment, the front tip is topped by a bell-shaped front body.

 According to yet another characteristic, the assembled projectile comprises from its front end to its rear end, a substantially continuous external profile, devoid of groove or shoulder.

 For example, a curved front part is connected by a soft junction to a straight rear part.

 In one embodiment, the joining part of the profile is substantially frustoconical and / or curved inwards.

 Another object of the invention is a munition such as a cartridge, of the type comprising a case enclosing an explosive charge and a primer, the cartridge comprising a projectile as mentioned, on which is crimped, at the rear guide, the case.

 According to one characteristic, the case is crimped at the rear guide, near a portion projecting longitudinally from the fitted core.

 According to one characteristic, the ammunition is of small caliber, for example a caliber 7.62 or the like.

 Other characteristics and advantages of the invention appear from the following description of embodiments given by way of example, and which refers to the accompanying drawings.

Figure 1 is a schematic exploded perspective view of an ammunition or cartridge according to an embodiment of the invention, on which a core and separated from a projectile guide, the latter being rigidly secured to a cartridge case
Figure 2 is a schematic half-sectional view of a projectile according to the invention, along a radial plane of longitudinal elevation
Figure 3 is a schematic sectional view along line III-III of Figure 2
Figure 4 is an enlarged partial schematic view of detail IV in dotted lines in Figure 3
Figure 5 is a schematic exploded perspective view of a second embodiment of the projectile of the invention, with a rear concavity core for the introduction of a heel of the projectile
Figure 6 is a schematic elevational perspective view of a third embodiment of the piercing core according to the invention, with on its warhead, an attached bell and rear undoigt with curved end
Figure 7 is a sectional view perpendicular to a longitudinal axis, of a housing guide of hexagonal section
Figure 8 is a sectional view perpendicular to a longitudinal axis, of a core for the hexagonal housing guide of Figure 7; and
FIG. 9 is a view in section perpendicular to a longitudinal axis, of the core of FIG. 8, fitted in the guide with hexagonal housing of FIG. 7.

 The figures show mutually orthogonal directions X, Y and Z.

 The so-called longitudinal direction X corresponds to the main direction of movement of a projectile when it is fired.

 The directions Y and Z, respectively called transverse and lateral, are substantially radial to the longitudinal direction X.

 The invention is described here with reference to these directions X, Y and Z.

 The constituents of the invention are described in their current positions and orientations of use.

But it goes without saying that they can take various positions or orientations.

 This is particularly the case for displaceable directions, for example during a shot. Thus, the directions Y and Z rotate around the direction X during a rotation of a projectile fired with a striped cannon.

 Likewise, the storage positions and orientations of the constituents of the invention may be different.

 These positions and orientations are therefore indicated for explanatory purposes only.

 It is specified here that the terms "front" and "rear" are considered in the longitudinal direction X, respectively as indicating a location towards a warhead and towards a base of a projectile.

 While the terms "interior" or "internal" and "exterior" or "external" are considered in a radial direction such as Y or Z, respectively as indicating a location towards a median longitudinal axis and towards an external contour.

 Finally, the terms "longitudinally", "laterally" and "transversely" refer to the corresponding directions.

 In the figures, the reference 1 designates a projectile intended for ammunition 2 according to the invention.

 This ammunition 2 is intended to be fired with a rifled gun.

 The projectile 1 comprises a rear guide 3 and a front core 4.

 In the figures, the projectile 1 is of the piercing type.

 In this case, the material or materials of the core 4 are chosen as a function of their qualities of penetration into the target medium, and are of a higher hardness than that (s) of the guide 3.

 But this projectile 1 is also intended for other types of ammunition 2, in particular ordinary ammunition, incendiary perforators, perforating-tracers, perforating-incendiairestraçants, incendiaries, tracers, and explosives.

 Then, the choice of the material or materials of the core 4 is determined according to the type of projectile.

 In embodiments, the guide is made of copper, brass, synthetic material such as polyurethane or PTFE.

 While the material or materials of the rear guide 3 are chosen in order to ensure optimal contact with the scratches of the barrel, and to allow that the latter can deform this guide 3 with the least possible constraints.

 In embodiments, the core is made of steel, alloyed or not, aluminum, zamak or charged or unloaded synthetic material.

 In FIG. 1, the ammunition 2 or cartridge, comprises a case 5 enclosing an explosive charge 6 of propulsion and a primer 7 for ignition.

 The cartridge 2 comprises a projectile 1, on which the case 5 is crimped, at its rear guide 3.

 In FIG. 1 or 2, the case 5 is crimped inwards at the level of a frustoconical region 8 of the guide 3, close to its external junction with the core 4.

This region is described below.

 For this crimping, a slight external groove can be made on the guide, but so that the latter can nevertheless be considered as externally substantially smooth.

 According to the embodiments illustrated, the ammunition 2 is of small caliber, for example a caliber 7.62 or the like.

 But other sizes are possible, larger for example up to 20mm, or smaller.

 Projectile 1 is described more precisely.

 The rear guide 3 and the core 4 are assembled by positive stress fitting.

 To this end, the rear guide 3 comprises an internal housing 9 generally extended along a median longitudinal axis 10 of the projectile 1.

 As can be seen from the figures, the median axis 10 is parallel to the longitudinal direction X, and substantially at the center of each section of the projectile 1, perpendicular to this direction X.

 The housing 9 opens out towards the front of the projectile 1, at a front end of the region 8 of the guide 3.

 This end defines a front abutment surface 11, substantially perpendicular to the axis 10.

 A stop shoulder 12 provided at the rear on the core 4 is provided to come against the surface 11 of the guide 3.

 Thus, the relative position of the guide 3 and the core 4 in the direction X is defined during their assembly.

 It is noted that for this purpose, a free space 13 or clearance is provided between a rear end 14 of the core 4, and a bottom 15 of the housing 9 of the guide 3.

 In FIGS. 1, 2 and 5, the rear end 14 is in the general shape of a plane substantially perpendicular to the axis 10.

 In FIG. 6, this end 14 is of convex shape, with its convexity turned towards the rear of the core 4, that is to say towards the bottom 15 when the projectile 1 is assembled.

 To ensure a conical fitting, the main generator 16 of the housing 9 is substantially inclined relative to the longitudinal axis 10.

 More precisely, it is inclined from the inside to the outside, from the rear to the front of the guide 3.

 In FIG. 5, the generator 16 is substantially inclined relative to the longitudinal axis 10, by an angle 17 of the order of 10 to 50, and in particular of the order of 3.

 Therefore, the housing 9 has a flared shape from rear to front, so that the section perpendicular to the axis 10 of its bottom 15 is less in area than that which is delimited internally by the abutment surface 11.

 In FIGS. 1, 4, 5 and 7, it can be seen that an outer wall 18 of the guide 3 is smooth.

 In the case where a crimping groove of the case 5 is provided on the outside of the guide 3, the latter is then substantially smooth, due to the shallow radial depth of the groove, without significant influence on the ballistics of the projectile 1.

 While an internal wall 19, which is somewhat peripheral to the housing 9, has at least three faces 20.

 Each face 20 is substantially flat and extended perpendicular to a radial direction, for example Y or Z, orthogonal to the median longitudinal axis 10.

 These planar radial faces 20 form means 24 for absorbing masses of material from the guide 3, deformed under the effect of scratches from the barrel when fired.

 Thus, not only are the stresses involved when taking scratches are limited, but also the increase in stress during this taking are made progressive, by increasing the contact surface between the guide 3 and the core 4.

 The increase in thickness of the guide induced by the conical angle 17 of the housing 9 and, as seen below, of the core 4 is thus used optimally.

 According to the examples of FIGS. 1, 2 and 5, each of the faces 20 is extended substantially from the bottom 15, to the transverse end defined by the surface 15 of the housing 9.

 In this way, the absorption means 24 formed by the faces 20 open out at the front.

 The faces 20 of a guide 3 intended for the core 4 of the example of FIG. 6, may not be extended rearward to the bottom 15, due to the convex shape of the end 14 of this core 4.

 In the figures, each face 20 is extended so as to define two edges 21, substantially parallel in radial projection, to the median longitudinal axis 10.

 In FIGS. 7 and 9, the housing 9 has contiguous planar faces 20, so that the section transverse to the median longitudinal axis 10 of the housing 9 is hexagonal.

 In embodiments, the section of the housing 9 is polygonal with four, five, seven or nine sides.

 In FIGS. 1 to 5, the section of the housing 9 comprises substantially planar absorption faces 20, on only part of the periphery of the internal housing 9.

 The means 24 are therefore here in the form of wide grooves, spaced apart by bearing surfaces 22 in the form of a conical cylinder section.

 FIG. 3 shows a projectile 1 with faces 20, regularly distributed along the periphery of the housing 9, and spaced apart by ranges 22.

 The angular difference, in a plane perpendicular to the median longitudinal axis 10, between two edges 21 either spaced by a surface 22, or by a face 20, is substantially equal on the periphery of the housing 9.

 In the example of FIGS. 7 to 9, the edges 21 define substantially identical angular spaces over the entire internal periphery of the housing 9.

 In FIG. 9, the ratio between the cross-sectional area in a plane perpendicular to the longitudinal axis 10, of the core 4 and of the housing 9 is of the order of 0.937.

 Therefore, the absorption means 24 have an area in section in this plane, of the order of 6.68 of the area of the core 4.

 More generally, the area of the absorption means 24 or vacuum remaining after assembly of the guide 4 and the core 3, is determined so that it is more extensive than the corresponding male area of the barrel scratches with which the projectile 1 is planned to be fired.

 We thus obtain that these scratches print without harmful alteration, in projectile 1, when fired.

 The core 4 obviously comprises at the rear, additional fixing means 23 for fitting into the housing.

 By complementary, it is meant here that these means 23 allow a positive fitting in the housing 9, by leaving the voids formed by the means 24 for mass evacuation.

 In the figures, these means 23 consist of a finger 25 generally frustoconical.

 In FIG. 5, the finger 24 is provided on the side of its small base, at the end 14, with a conical internal cavity 26, emerging at the rear of the core 4.

 In the figures, the finger 25 is of section perpendicular to the median axis 10, as seen in FIG. 3 or 8.

 This cavity 26 is intended to receive a heel 27 of the projectile 1.

 In FIG. 6, a nose cone or front point 28 of the perforating core 4 is of shape substantially symmetrical to that of the frustoconical finger 25 with rounded end 14, with respect to a plane perpendicular to the axis 10.

 This front point 28 is capped by a front body 29 in the shape of a bell.

 The bell 29 is here in a hard material chosen for its perforation qualities.

 While the material of the finger 25 and the front tip 28 are chosen in particular for their fitting qualities in the housing 9, in particular.

 In general, the projectile 1 comprises from a front end 30, that is to say the point of a warhead 28 or of the bell 29, to its rear end 31 opposite in the direction X, an external profile substantially continuous, without throat or shoulder.

 In FIG. 1, this external profile comprises a curved front part 32 connected by a soft junction 33 to a rear part 34 straight and parallel to the direction X.

 In Figures 1 and 2, the junction portion 33 of the profile is substantially frustoconical and / or curved inward.

 More specifically in FIG. 1 or 5, the front part 32 is curved and the junction part 33 is substantially frustoconical and slightly curved.

 In FIG. 2, the joining part 33, both on the core 4 and on the guide 3, has a similar shape and in continuity, while its front part 32 is curved.

 The front end 30 of the core 4 is substantially planar.

 It is understood that the invention allows the masses of the deformed material to be absorbed by the means 24 of the internal wall of the rear guide 3.

 The friction of the projectile 1 with the barrel is thus limited, while retaining good cooperation between the scratches of the barrel and this projectile 1.

 In addition, when the projectile 1 penetrates into a medium comprising fibers, its substantially smooth outer wall prevents the fibers from finding a point of attachment and thus limiting the speed of perforation of the projectile 1.

Claims (19)

 1. Projectile (1) for rifled barrel firearm, comprising a rear guide (3) and a core (4), assembled by positive stress fitting; the rear guide (3) comprising an internal housing (9) generally extended along a median longitudinal axis (10) of the projectile (1), and opening out towards the front and whose generator (16) is substantially inclined relative to the longitudinal axis (10), from the inside to the outside from the rear to the front of the guide (3); while the core (4) comprises at the rear, means (25) for complementary fitting of fitting in the housing (9);  characterized in that the outer wall of the rear guide (3) is smooth, while the inner wall of the housing (9) has at least three faces (20) substantially planar and extended perpendicular to a radial direction orthogonal to the axis (10 ) median longitudinal, for example lateral or transverse  these faces (20) forming means (24) for absorbing masses of material from the guide (3), deformed under the effect of the barrel scratches during firing.  2. Projectile (1) according to claim 1, characterized in that the generator (16) is substantially inclined relative to the longitudinal axis (10), from the inside to the outside from the rear to the front of the guide (3), of an angle (17) of the order of 10 to 50, and in particular of the order of 30.  3. Projectile (1) according to claim 1 or 2, characterized in that, projectile (1) being perforating, the hardness of at least one front part of the core (4) such as point, ogive (28) or bell ( 29), is greater than that of the guide (3).  4. Projectile (1) according to one of claims 1 to 3, characterized in that at least one face (20) is extended substantially from a bottom (15) to a transverse end (11) of the housing (9 ) forming a stop for the core (4), so that the corresponding absorption means (24) are through, for example all the faces (20) of the housing (9) are extended substantially from the bottom to the end (11) forming stop.  5. Projectile (1) according to one of claims 1 to 4, characterized in that at least one face (20) is extended so as to define two edges (21) substantially parallel in radial projection, to the axis ( 10) median longitudinal.  6. Projectile (1) according to one of claims 1 to 5, characterized in that the housing (9) has at least two contiguous faces (20), for example, all the faces (20) are contiguous so that the section transverse to the median longitudinal axis (10) of the housing (9) is polygonal with four, five, seven or nine sides.  7. Projectile (1) according to claim 6, characterized in that the polygonal section of the housing (9) has six faces (20) and its cross section to the longitudinal axis (10) is therefore hexagonal.  8. projectile (1) according to claim 6, characterized in that the polygonal section of the housing (9) has eight faces (20) and its cross section to the longitudinal axis (10) is therefore octagonal.  9. Projectile (1) according to claim 6, characterized in that it (1) comprises faces (20) absorption means (24) on only part of the housing (9) internal of the guide (3) rear , in the form of wide grooves, for example the projectile (1) comprises from eight to sixteen faces (20), and in particular twelve faces (20), for example regularly distributed along the periphery of the housing (9).  10. Projectile (1) according to one of claims 1 to 9, characterized in that the angular deviation in a plane perpendicular to the median longitudinal axis (10), between two edges (21) spaced apart by a face (20 ) and / or between two faces (20), is substantially equal for at least two spacings and / or faces (20), for example the edges (21) define substantially identical angular spaces over the entire internal periphery of the housing (9) .  11. Projectile (1) according to one of claims 1 to 10, characterized in that the area of the absorption means (24) or vacuum remaining after assembly of the guide (3) and the core (4) is determined for that they (24) are more extensive than the corresponding male area of the stripes of the destination gun.  12. Projectile (1) according to one of claims 1 to 11, characterized in that the ratio between the area in section in a plane perpendicular to the median longitudinal axis (10), of the core (4) and of the housing (9) of guide (3) is of the order of 0.85 to 0.95, and in particular of the order of 0.937, for example, the absorption means (24) have an area in section in a plane perpendicular to the median longitudinal axis (10), of the order of 5% to 10% of the area of the core (4), and in particular of the order of 6.68.  13. Projectile (1) according to one of claims 1 to 12, characterized in that the substantially complementary means for fitting the core (4), comprise a tapered finger (25), provided on the side of its small rear base, an internal conical cavity (26), emerging at the rear of the finger (25) and intended to receive a heel (27).  14. Projectile (1) according to one of claims 1 to 13, characterized in that a warhead or point (28) before the perforating core (4) is of shape substantially symmetrical to that of a tapered finger (25) of this core (4), relative to a plane perpendicular to the transverse median axis (10).  15. Projectile (1) according to one of claims 1 to 14, characterized in that a point (28) before or ogive of the core (4) is topped by a front body (29) in the shape of a bell.  16. Projectile (1) according to one of claims 1 to 15, characterized in that it (1) comprises from its front end (30) to its rear end (31), a substantially continuous external profile, devoid of groove or shoulder, for example a curved front part (32) is connected by a soft junction (33) to a straight rear part (34).  17. Projectile (1) according to claim 16, carcatized in that the junction part (33) of the profile is substantially frustoconical and / or curved inwards.  18. Ammunition (2) such as cartridge, of the type comprising a case (5) enclosing an explosive charge (6) and a primer (7), and a projectile (1) according to one of claims 1 to 17, on which (1) is crimped the case (5), at the level of the rear guide (3);  characterized in that the case (5) is crimped at the rear guide (3), near a longitudinally projecting part of the fitted core (4).  19. Ammunition (2) according to claim 1S, characterized in that it (2) is of small caliber, for example a caliber 7.62 or the like.