US 3851590 A
A one-piece flechette projectile is disclosed, having a long thin shank with a tapered nose and a finned rear section, the nose section and finned section being softer than the central shank section to afford curling and tumbling on impact.
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Description (OCR text may contain errors)
United States Patent [191 LaCosta Dec. 3, 1974 MULTIPLE HARDNESS POINTED F INNED PROJECTILE  Inventor: Nicholas Joseph LaCosta, Phoenix,
 Assignee: AAI Corporation, Cockeysville, Md.  Filed: Dec. 30, 1966  App]. No.: 606,454
 US. Cl. 102/92J, 102/D1G. 7  Int. Cl. F42b 13/00  Field of Search 102/38, 42, 52, 53, 67, 102/91, 92.], 92.4, 92.7; 244/324; 273/106,
 References Cited UNITED STATES PATENTS 1,276,892 I 3/1913 Fender 244/327 3,072,054 1/1963 Ashbrook 102/38 X Primary Examiner-Verlin R. Pendegrass Attorney, Agent, or FirmReginald F. Pippin, Jr.
 ABSTRACT A one-piece flechette projectile is disclosed, having a long thin shank with a tapered nose and a finned rear section, the nose section and finned section being softer than the central shank section to afford curling and tumbling on impact.
10 Claims, 6 Drawing Figures PATENTE'U BEE 3i974 Fig.2
m ||3 xi g E X Fig.3
N lCHOLAS J. LOCOSTA INVENTOR Fi g. 6 g Mi ATTORNE;
MULTIFLE HARDNIESS lPflllN'lflElD lFllNNElD PROJEC'HIILE This invention relates to fin-stabilized projectiles and is particularly applicable to small needle-like finned projectiles commonly referred to as flechettes or flechette projectiles.
Flechette projectiles such as shown in US. Pat. No. 2,939,395 are highly advantageous in their ability to travel long distances at high velocities, with good accuracy. For maximum effectiveness as an anti-personnel weapon it is desirable that these flechettes curl and/or tumble upon impact with a target. It has been found that this curling and/or tumbling action can be effected with a included angle pointed end, particularly in the case of a projectile made of 1065 steel and approxi mately 0.070 inches shank diameter; however, in the handling of projectiles with this sharp point, the point tends to get bent very easily, with substantial reduction in downrange velocity during flight. In an attempt to remedy this difficulty, a finned projectile has been formed with this 10 included angle tapered forward end, but with a tapered forward nose end of approximately one-tenth to one-fifth of the diameter of the shank or main body of the projectile, in order to minimize the danger of deformation of the point during handling, as in assembly of the projectile. However, this flat or blunt-nosed projectile has been unsatisfactory in effecting the desired curling and/or tumbling action upon impact. It is accordingly a major feature of the present invention to provide an improved projectile in the form of a flechette which is capable of reasonable accuracy in flight, will curl and/or tumble in the desired manner after impact and during passage through a rela tively soft, dense target, such as an animal, and is capable of reasonable handling in assembly without deformation of the point.
Still other objects, features and attendant advantages will become apparent to those skilled in the art from a reading of the following detailed description of a single embodiment constructed in accordance with the invention, taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a perspective view of a flechette according to the invention,
FIG. 2 is a side elevation view of the flechette of FIG.
FIG. 3 is a side elevation view of a modified flechette according to the invention,
FIG. 4 is a schematic illustration of a flechette according to FIG. 2, impact, and particularly in a typical deformed condition that it may assume during tumbling after impact,
FIGS. 5 and 6 are schematic illustrations similar to that of FIG. 4 and illustrating various deformed configurations assumed by the modification of FIG. 3 after impact.
Referring now in detail to the Figures of the drawings, a flechette projectile 11 is provided, having a smooth walled cylindrical main body section or shank 13, with a tail section 15 having stabilized fins 15a formed thereon as by swaging of the metal from the cylindrical body section into the configuration as indicated in FIG. 1. The forward end of the projectile has a tapered nose section 17, terminating in a flat nose end 170. A projectile formed of this configuration and being of equal hardness along its length will normally not effectively curl or tumble upon impact to any substantial degree, but will proceed into the target in a generally straight linear fashion. I have found, however, that by providing selected different heat treatments of the projectile along its length desired curling and/or tumbling action will result upon impact of the projectile with a target. In the embodiment of FIG. 2 the forward section A of the projectile, which is approximately 25 35 percent of the projectile length, is heat treated to a softer condition than the remaining rear section B, including the main cylindrical body portion of the shank 13, and the rearmost finned zone 15. In one preferred physical embodiment, in which the flechette has a length of 1.6 1.7 inches, a shank diameter of 0.070 inches, a point taper included angle of 10, and a flat nose end 17a of 0.005 0.015 inches, and which is particularly adapted for employment in cartridges of 0.22 caliber ammunition, the softer zone A extends over a length of approximately 0.5 inches, and the hardness of the forward end section A is annealed to R 20, while the rear section was treated to a hard ness value of RAM) to 50.
In the operation of the embodiment of FIG. 2, as illustrated schematically in FIG. 4, the soft forward end section A will begin curling upon impact, and the projectile will commence tumbling during passage through the soft, dense target material, somewhat in the general direction as indicated by the arrow in FIG. 4. The projectile may thereafter continue its curling action past the soft zone A and into a substantial portion of the heat treated harder zone B, and the tail section 15 and adjoining portion of the shank 113 will generally remain somewhat straight, or generally straighter than the forward curved portion, as indicated schematically in FIG.
It will be readily apparent that increased effectiveness is obtained with this projectile in a soft, dense type target, such as an animal, due to the tumbling and enlarged effective projected peripheral area of the projectile in the tumbling curled configuration of FIG. 4 as compared to the small piercing configuration of the projectile if it should pass into or through the target in a straight linear fashion.
In the modification of FIG. 3, the forward section A is annealed to a softer hardness as in the embodiment of FIG. 2, the section B is heat treated to a harder value, but is of less length than the similar harder section B in the embodiment of FIG. 2 and extends along the mid-section of the projectile, whereas the rearmost tail fin section C is also annealed to a softer hardness value generally corresponding to that of the forward section A. The relative length of the sections A, B and C in one illustrative and operationally effective example of this embodiment are respectively approximately 0.5 inch, 0.65 inch, and 0.5 inch (it being appreciated that approximate figures are given as there is a short zone of hardness transition between sections A, B and C), the remaining overall dimensions of the projectile being the same as in the preceding described embodiment.
In operation of this modified embodiment the projectile will commence curling and/or tumbling in the same manner as with the projectile of FIG. 2; however, in this embodiment the rearmost section C will also deform more easily than the harder rearmost section of the first embodiment, resulting in some tendency for a more tightly curved rear section in the curled configuration, as indicated in FIG. 5. In addition, this tendency of the rear section to bend relatively easily compared to the center section B will increase the tendency of the projectile to initiate tumbling and curling action, as the projectile tends to bend from both ends during passage through the target although the initial and major curling action will normally be effected along the impact end section A. In either embodiment but particularly in this second embodiment, the stabilizing fins a may sometimes be sheared from the adjoining section 15 of the projectile upon impact, or the tail section 15 may be entirely broken away from the remaining body portion, as indicated schematically in FIG. 6.
While the invention has been illustrated and described with respect to several illustrative physical embodiments constructed in accordance therewith, it will be apparent to those skilled in the art that various modications may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited by the particular illustrative embodiments, but only by the scope of the appended claims.
That which is claimed is:
l. A one-piece projectile adapted to curl and tumble on impact with a target, comprising:
a long slim shank section,
a rear stabilizing fin section integral with said shank section, and
a tapered front section integral with said shank section,
said shank, fin section, and front section being integral and of the same material,
the material of said projectile being substantially softer at its forward end zone than along a zone thereof rearward of its forward end.
2. A projectile according to claim 1, said softer forward end zone being annealed, and said rearward zone being heat treated to a substantially harder state than said forward end.
3. A projectile according to claim 1, said forward end zone hardness being of a value less than R25, and said harder rearward zone being of a value greater than R 35.
4. A projectile according to claim 3, said rearward zone hardness lying between R 40 and R50.
5. A projectile according to claim 4, said forward end zone hardness being R 20.
6. A projectile according to claim 1, said softer forward end zone extending along approximately 25 35 percent of the projectile length.
7. A projectile according to claim 1, the material of said rear stabilizing fin section being substantially softer than the material of the interconnecting intermediate said zone rearward of said forward end zone.
8. A projectile according to claim 6, said softer forward end zone and said softer rear finned section being of substantially similar hardness.
9. A projectile according to claim 1, said shank section being cylindrical and said tapered front section having a frusto-conical configuration with a substantially flat tip end, said softer forward end zone extending rearwardly beyond said frusto-conical configuration and along a substantial interconnecting portion of said cylindrical shank section.
10. A flechette projectile according to claim 9, said projectile having a length of approximately 1.6 1.7 inches, a one shank diameter of 0.065 0.075 inches, a forward end taper of 10, a flat tip end diameter of 0.005 0.015 inches, and said softer forward zone extending approximately 30 percent of the projectile length.