DK165523B - PROJECTILE AND SABOT AT GREAT SPEED - Google Patents

Abstract

A high velocity ammunition sabot (16) of brittle material which has sufficient strength to withstand the forces of being launched from a rifled gun barrel but which fragments almost immediately upon exit from the barrel due to centrifugal forces. A polyetherimide material is preferred, although materials of equivalent properties could be used.

Description

DK 165523B

BACKGROUND OF THE INVENTION The present invention relates to small-caliber rifle ammunition consisting of a projectile mounted in a disintegrating plastic sabotage which stabilizes the projectile upon its firing through the rifle but which disintegrates as it exits the mouth of the barrel so that only the projectile proceeds to the target.

"Small caliber" in the present application is used in the sense of a caliber of 0.50 inch (about 12.7 mm) or less. Virtually no development has taken place in the field of small-caliber sabotages in plastic following the development of the hunting-ammunition plastic sabotage disclosed in U.S. Patent No. 3,164,092 to the well-known "Accelerator" hunting cartridge from Remington, using a lead projectile in a polycarbonate sabot. Similarly, 15 built-up sabotas are disclosed in U.S. Patent No. 3,311,061.

There is still a desire to be able to increase the speed, hardness and density of sub-calibrated lightweight rifle projectiles so that they can penetrate harder and thicker targets. However, how this should be done in conjunction with known rifles has been unknown because of the denser projectile material required for this and the inability of known sabotages, such as disclosed in the above-mentioned U.S. Patent No. 3,164. .092, to withstand the forces transmitted by such broadcasts. In general, such sabots are designed to be torn away from the projectile by the launch as a single unit, and experience has gone against the use of brittle materials in the construction of a sabot, breaking such material instead of being torn away.

The problem is solved by a projectile and a sabot of the type mentioned at the outset, which are characteristic of being designed as set forth in claim 1 and 1, respectively. The characteristic part of claim 10.

In the present invention, there is provided a small-caliber projectile which consists of a sabot sufficiently strong to be carried out of a rifled barrel.

DK 165523B

2 one piece at maximum chamber pressure of more than 70,000 "copper crusher" printing units (CUP), but which is then immediately disrupted so that it does not subsequently reduce the projectile speed or render the projectile inaccurate. Compared to those of US Patent Nos. 3,164,092 and Nos.

3,311,061 said sabots distinguish the sabot provided by the present invention by being made of a relatively brittle material which is broken by the projectile's firing rather than being torn away.

The present invention provides a small caliber projectile (12.7 mm or less) which consists of a sub-calibrated, hard, armor piercing metal core located axially in a plastic sabot, which sabot frees from the core almost immediately. when the projectile for-15 leaves the rifle barrel after firing. The sabot consists of a sleeve which is closed at one end and open at the other for insertion of the core, the closed end of the sabot being formed with a solid bottom located at the rear of the core and the sabot being constructed of a plastic material having sufficient tensile strength, shear strength and compressive strength to withstand the explosive emission of the projectile from the barrel of an rifle with an intact sabot before releasing it from the projectile while the sabot is made up of a relatively brittle plastic material which cannot overcome the centrifugal force and the aerodynamic forces affecting the sabot as the projectile exits the rifle, as these forces cause the sabot to disintegrate almost immediately after the projectile has left the barrel, thus releasing the core that it can continue in its lane unhindered.

Further, the invention provides a sabot for use in such a projectile, which sabot consists of a sleeve which is closed at one end and open at the other end for insertion of the core, the closed end of the sabot being formed with a solid base located 35 at the rear of the core, and the sabot is constructed of a plastic material of sufficient tensile strength, shear strength and 3

DK 165523 B

compressive strength to withstand the explosive emission of the projectile from the barrel of an rifle with an intact sabot before releasing it from the projectile while the sabot is made up of relatively brittle plastic material of insufficient strength to withstand the centrifugal force and the aerodynamic forces which affects the sabot as the projectile exits the rifle barrel, these forces causing the sabot to disintegrate virtually immediately after the projectile has left the barrel, thereby releasing the core so that it can continue in its trajectory unhindered.

It is preferred that the sabot be made of a plastic material having a tensile and shear strength (ASTM D 1708 and ASTM D 732, respectively) of at least 12,000 psi (82.74 MPa), a compressive strength of at least 15,000 psi (103.43 15 MPa) ) and an Izod notch impact test (ASTM D 256) under ca. 12 feet-pounds / inches (6.4 Nm / cm). The most preferred plastics materials are (a) thermoplastic, amorphous polyetherimide resin, (b) thermoplastic polycarbonate resin reinforced with 20 glass fibers.

(c) thermoplastic polyetherimide resin reinforced with glass fibers.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which: 1 is a sectional view taken along the axis through a sabot and projectile provided by the invention; FIG. 2 is an isometric view of the embodiment of FIG. 1, which is used in the projectile.

A projectile 10 is shown with a larger cylindrical 30 rear portion 12 which is guided in a centered bore 14 on a generally cylindrical shaped sabot 16 of plastic formed with a solid cylindrical rear base 18 and a tubular front portion 20. The front portion 20 includes a plurality of curved portions 22, which are joined by attenuated 35 pieces 24 extending axially on the front portion 20. The attenuated pieces 24 are formed with spaced apart ones.

DK 165523B

4 axial grooves or joints 26 on the inner surface of the front portion 20 and are tapered at the inner ends to concentrate fracture forces at these points so that the sabot's fracture lines are predetermined to some extent. The outer surface 28 of the sabot 16 is formed as an unbroken cylinder surface.

Between the bottom 30 of the bore 14 of the sabot 16 and the rear end 32 of the projectile 10 is placed a square disc 34 of metal and with rounded corners (also shown in Fig. 2), which disc is radially inward and outwardly relative to the inner surface of the center bore 14 so that the disk transmits the accelerating forces during the explosive of shooting sabot 16 and projectile 10 together through a rifled rifle barrel (not shown) and to prevent a rotational slip between sabot 16 and disk 34 during the rotational acceleration of the sabot 16 during such an extension. The disc 34 may be formed in another non-circular, symmetrical manner, in that it may be formed as a polygon (pentagon or hexagon, etc.), an ellipse or as a gear. The disc 34 is formed with rounded corners to reduce impact concentrations in the corners and to enable the use of larger area discs.

The outer surface 28 of the sabot 16 is formed with a substantially constant diameter from base portion 18 up to an axial point 36, located in front of the center of gravity 38 of the projectile 10 to reduce uncontrolled movements of the projectile 10 during its passage through a rifled rifle barrel. which could occur if the point 36 was located behind the center of gravity 38. In another embodiment, 30 shown contoured, a heavier projectile 10a is shown mounted in an identical sabot and with a center of gravity 38a which is also behind the point 36.

Sabot 16 is provided with a 7.62 mm caliber and carries a 52 grain (approx. 3.4 g) tungsten projectile 10 or a 57 grain (approximately 3.7 g) tungsten projectile 10a. Other calibers for sabot 16, such as 5.56 mm or 5

DK 165523 B

caliber 0.50 could also be used and other sizes, materials and designs of the projectiles 10 could be suitable if desired.

The plastic material for the sabot 16 is one such material, with sufficient tensile strength (at least 12,000 psi (82.74 MPa)), compressive strength (at least 15,000 psi (103.43 MPa)), shear strength (at least 12,000 psi (approx.

82,700 kp)) to withstand the shock of the explosive firing from a rifled rifle barrel with the projectile 10, but 10 with insufficient (less than 12 feet-pound / inch 6.4 Nm / cm) strength in the Izod notch impact test to withstand the centrifugal and aerosynamic forces following the launch so that the sabot 16 disintegrates immediately after (i.e., within a yard (about 90 cm) of leaving the runway 15, thereby immediately releasing the projectile 10 for unobstructed flight towards the target.

A suitable plastic material is the "ULTEM 1000", which is an unadjusted amorphous polyetherimide thermoplastic resin marketed by General Electric Company. Other plastics materials which are believed to be suitable are ULTEM 2200, a 20% glass reinforced polyether imide resin and LEXAN 3412, a 20% glass reinforced polycarbonate resin, both from General Electric Company and TORLON 4203L build-up resin from Amoco Chemicals Corporation. Other plastics materials having similar mechanical properties could be used if the mechanical properties of the plastics material are not chemically degraded when exposed to propellants of the kind with which it is to interact.

Claims (11)

A small calibrated (12.7 mm or less) projectile consisting of a sub-calibrated, hard, armor-piercing metallic core (10) located axially in a plastic sabot 5 (16), which sabotages itself from the core almost immediately divisible by the projectile's exit from the rifle barrel after firing, the sabot (16) consisting of a sleeve (20) closed at one end (18) and open at the other end for insertion of the core, and the closed end (18) of The sabot 10 is formed with a solid base located at the rear of the core (10), and the sabot is constructed of a plastic material of sufficient tensile, shear, and compressive strength to withstand the explosive emission of the projectile from an rifle barrel with an intact sabot. before it is released from the projectile, characterized in that the sabot is made up of a relatively brittle plastic material which cannot overcome the centrifugal force and the aerodynamic forces which affect the sabot when the projectile leaving the rifle barrel, these forces causing the sa-bot to disintegrate virtually immediately after the projectile has left the rifle barrel, thereby releasing the core so that it can continue its trajectory unhindered. Projectile according to claim 1, characterized in that the sabot is made of a plastic material having tensile strength and shear strength (ASTM D 1,708 and ASTM D 732, respectively) of at least 12,000 psi (82.74 MPa), a compressive strength of at least 15,000 psi (103.43 MPa) and an Izod notch impact test (ASTM D 256) below approx. 12 feet-pounds / inches (6.4 Nm / cm). Projectile according to claim 1 or 2, characterized in that the plastic material is (a) thermoplastic, amorphous polyetherimide resin, (b) thermoplastic polycarbonate resin reinforced with glass fibers, (c) thermoplastic polyetherimide resin reinforced with glass fibers. DK 165523 B Projectile according to claims 1-3, characterized in that the sabot includes a cylindrical body (16) with a rear base part (18) and an open front part (20) with a centered bore 5 (14) surrounding and occupies the rear portion (12) of the core (10). Projectile according to claim 4, characterized in that the front part (20) of the sabot is provided with 10 spaced axial grooves (26) which divide the front part (20) of the sabot. a plurality of curved segments (22) interconnected by attenuated pieces (24), said segments (22) and pieces (24) forming a smooth, unbroken cylinder surface on the sabot (16). Projectile according to claim 5, characterized in that the grooves (26) extend axially, but only on part of the piece from the open front end of the sabot towards the base part (18), and are tapered at their inner ends, impact transmitted to the sabot when leaving the rifle is concentrated at a number of points spaced apart on the sabot so that the sabot's disintegration is guided along relatively predictable paths. Projectile according to claim 6, characterized in that the front end of the sabot is provided with a reduced diameter back to a point in front of the center of gravity of the projectile, thus further weakening the front part of the sabot to promote separation. of the segments (22) during rupture, while still providing a sufficient sealing surface to minimize uncontrolled movement of the projectile during the firing. Projectile according to claims 1-7, characterized by including a symmetrical, non-circular, centrally pierced flat metal plate (34) located in the sabot (16) between the base part (18) of the sabot (16) and the rear end (32) of the core DK 165523 B (10). Projectile according to claim 8, characterized in that the plate (34) is square with rounded corners. The small-caliber sabot (12.7 mm or less) projectile as claimed in claim 1, said sabot (16) consisting of a sleeve (20) closed at one end (18) and open at the other end for inserting the core, the closed end (18) of the sabot being formed with a solid bottom located at the rear of the core (10), and the sabot being constructed of a plastic material of sufficient tensile, shear and compressive strength to able to withstand the explosive emission of the projectile from the barrel of an intact sabot rifle before releasing it from the projectile, characterized in that the sabot is made up of a relatively brittle plastic material which cannot overcome the centrifugal force and the aerodynamic forces; which affects the sabot as the projectile exits the rifle barrel, these forces causing the sabot to disintegrate virtually immediately after the projectile has left the rifle barrel, thereby releasing the core so that it can continue tea in its lane unhindered. The sabot according to claim 10 with the features of claims 2-7.