U.S. patent application number 10/489514 was filed with the patent office on 2004-12-09 for frangible bullet.
Invention is credited to Jopson, Bill.
Application Number | 20040244629 10/489514 |
Document ID | / |
Family ID | 33490771 |
Filed Date | 2004-12-09 |
United States Patent
Application |
20040244629 |
Kind Code |
A1 |
Jopson, Bill |
December 9, 2004 |
Frangible bullet
Abstract
A frangible hollow point bullet is disclosed. The bullet (or
slug) is formed from a frangible material such as sintered copper
to provide a bullet-shaped body. A plurality of coaxial,
substantially cylindrical cavities having progressively decreasing
bore diameters are formed in the nose of the bullet-shaped body,
extending rearwardly therefrom, to provide a bullet that both
expands and fragments in a semicontrolled fashion upon impact with
a target. In a preferred embodiment, at least one of the coaxial
cavities is multiply scored to provide a substantially symmetric
fragmentation pattern and a controlled and uniform fragment size.
Controlling the aggregate depth of the coaxial cavities enables the
retention of a recoverable base or shank that is suitable for
ballistic investigation following bullet impact. Bullets and slugs,
made in accordance with the present invention, have standard
calibers and, when incorporated into conventional cartridges and
shotgun shell casings respectively, may be fired at subsonic, sonic
or supersonic velocities by conventional weapons.
Inventors: |
Jopson, Bill; (Goleta,
CA) |
Correspondence
Address: |
Michael G Petiti
PO Box 91929
Santa Barbara
CA
93190-1929
US
|
Family ID: |
33490771 |
Appl. No.: |
10/489514 |
Filed: |
July 1, 2004 |
PCT Filed: |
September 25, 2002 |
PCT NO: |
PCT/US02/30600 |
Current U.S.
Class: |
102/508 |
Current CPC
Class: |
F42B 12/367 20130101;
F42B 12/34 20130101 |
Class at
Publication: |
102/508 |
International
Class: |
F42B 030/00 |
Claims
What we claim is:
1. A substantially bullet-shaped projectile comprising a body
having a leading end, a trailing end and a frangible body portion
therebetween, and a plurality of cavities having cylindrical walls
extending rearwardly into said body portion from said leading end,
the diameter of said cylindrical walls of each cavity comprising
said plurality of cavities being progressively smaller in a
direction rearward of said leading end.
2. The projectile in accordance with claim 1 further comprising a
plurality of grooves on said cylindrical wall of at least one of
said plurality of cavities.
3. The projectile of claim 1 wherein said projectile is a
bullet.
4. The projectile of claim 2 wherein said projectile is a
bullet.
5. The projectile in accordance with claim 1 further comprising a
plurality of grooves on said cylindrical wall of each cavity
comprising said plurality of cavities.
6. The projectile of claim 5 wherein said projectile is a
bullet.
7. A projectile in accordance with claim 1 wherein said body
portion has a smooth outer surface.
8. A projectile in accordance with claim 2 wherein said body
portion has a smooth outer surface.
9. A substantially bullet-shaped projectile having a leading end, a
trailing end and a frangible body portion therebetween, and a
hollow cavity in said leading end of said body portion, said hollow
cavity comprising a plurality of coaxial cylindrical cavities
extending rearwardly into said body portion from said leading end,
the diameter of each cylindrical cavity comprising said plurality
of cavities decreasing stepwise in discrete increments in a
direction rearward of said leading end.
10. A projectile in accordance with claim 9 wherein at least one
said cylindrical cavity comprising said hollow cavity has a cavity
wall bearing stress risers thereon.
11. A cartridge comprising a projectile in accordance with claim
9.
12. A cartridge comprising a projectile in accordance with claim
10.
13. A substantially bullet-shaped projectile having a leading end,
a trailing end and a frangible body portion therebetween, and a
hollow cavity in said leading end of said body portion, said hollow
cavity comprising a plurality of coaxial conical cavities extending
rearwardly into said body portion from said leading end, the
diameter of each conical cavity comprising said plurality of
cavities decreasing stepwise in discrete increments in a direction
rearward of said leading end.
14. A projectile in accordance with claim 13 wherein at least one
said conical cavity comprising said hollow cavity has a cavity wall
bearing stress risers thereon.
15. A cartridge comprising a projectile in accordance with claim
13.
16. A cartridge comprising a projectile in accordance with claim
14.
17. A shotgun shell comprising a plurality of pellets wherein each
pellet comprising said plurality of pellets has an exterior surface
with a plurality of cavities thereon.
18. A shotgun shell comprising a plurality of pellets embedded
within a foam or a gel.
19. A shotgun shell comprising a projectile having a leading end
and a trailing end wherein said trailing end has a plurality of
fins attached thereto.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to ammunition and
more particularly to hollow point bullets or slugs and pellets
comprising a cartridge or similar projectile propulsion device.
[0003] 2. Description of the Prior Art
[0004] Recent events, particularly the hijacking of airplanes by
terrorists and the subsequent loss of life in the United States of
America, most notably in New York, Pennsylvania and Virginia, have
generated a need for new ideas for preventing airplane hijacking.
For example, it has been proposed that one or more armed air
marshals accompany scheduled airline flights to intervene in the
event of an attempted hijacking. Another proposed solution is to
arm pilots with weapons capable of selectively and accurately
dispensing lethal force against a hijacker. A disadvantage with
discharging a conventional weapon on an airplane wherein prior art
bullets are the projectile is the danger posed by the bullet
passing through the hijacker and striking another person or causing
damage to the avionics.
[0005] The nose portion of a hollow point bullet expands upon
impact with a target media thereby increasing the energy transfer
capabilities of the bullet. Typically, this expansion results in a
number of petals of metal being formed as the nose portion folds
back upon itself, thereby increasing the effective diameter of the
bullet. This expansion and resultant petal formation is referred to
as "mushrooming." A hollow point bullet may be solid or jacketed. A
solid bullet typically comprises a solid piece of metal, such as
lead or copper. A jacketed bullet typically comprises a lead core
surrounded by a harder metal, such as brass. The jacket is
relatively hard and slick, compared to the lead of the core, so the
bullet is more resistant to mechanical deformation by the action of
the gun as compared to the solid bullet.
[0006] Swank, in U.S. Pat. No. 5,943,749, discloses a bullet
comprising a slug of generally solid material having an outer
surface and a leading end portion having a cavity therein. A
plurality of grooves are formed on the outer surface of the end
portion. The end portion of the slug is contoured so that the
bullet has a predetermined shape. A plurality of slits may be
formed through at least a portion of each of the plurality of
grooves. Preferably, the plurality of grooves and slits are formed
substantially simultaneously. The slits are formed around a
peripheral edge of the leading end portion of the slug. A plurality
of projections, may be formed which extend into the cavity adjacent
to the slits. Each of the slits may be formed at an angle with
respect to a longitudinal axis of the slug to form each of the
projections. The cavity in the leading end portion has a truncated
cone geometry. Hollow Point (HP) projectiles can expand too
quickly, resulting in poor penetration, or can only partially
expand, leading to over penetration of a target and reduced energy
transfer to the target. In addition, hollow point bullets can fail
to expand, leading to severe over penetration or pass through.
[0007] Benini, in U.S. Pat. No. 6,263,798, discloses a frangible
bullet and a method for making it. The frangible bullet is formed
from a mixture of metal particles and metal or metalloid binder
material which is compacted into the desired shape and heated to a
target temperature. The target temperature is selected such that it
is above the temperature required to form at least one
intermetallic compound (but below the temperature of joining of the
metal particles by sintering), and below the temperature of
formation of substantial amounts of a ductile alloy of the metal of
the particles and the metal or metalloid binder material. The
bullet is then cooled. When such articles are formed into bullets
and fired at a target possessed of substantial mass, they have
sufficient strength to maintain their integrity during firing but
disintegrate into powder on impact. In addition, the bullet may
comprise a variety of metals other than lead.
[0008] Huffman, in U.S. Pat. No. 6,115,894, discloses an
armor-piercing frangible bullet, and provides a historic summary of
bullet development as well as a summary of test data obtained for
commercially available small arms ammunition. In particular
applications, it may be desirable to provide a hollow point,
frangible bullet that can be subjected to ballistic inspection
following impact with a target. Ballistic testing of a bullet
requires that a substantial portion adjacent the base of a bullet
(i.e., a shank) remain intact when presented for testing. Thus, it
is desirable to provide a bullet that may be designed to possess
attributes of both hollow point and frangible bullets and which,
upon impact with a target, retains a recoverable shank of
predetermined size that is suitable for ballistic characterization
and identification.
[0009] Most ammunition projectiles, particularly the newer non-lead
frangible projectiles, perform poorly in the sub-sonic range. Many
ammunition manufacturers use high velocities to enhance the
frangibility (break up) of the bullet upon impact. Prior art
frangible projectiles can fail to fragment if the chemical process
used to make the bullet is not carefully controlled. In addition,
such frangible bullets operate best when fired at very high
velocities, and are loaded by ammunition manufacturers at high
pressures. Further, the fragmentation pattern is random and
generally forms asymmetric clusters with respect to the direction
of the primary wound channel.
[0010] While both frangible bullets and mushrooming hollow point
bullets are known in the art, and wherein each has unique
attributes that recommend it for specific situations, there
continues to be a present and urgent need for improved bullets that
can be fired by conventional weapons such as pistols and will
minimize the danger of collateral damage in the event of a
hijacking or similar situation wherein shoot-through injuries to
innocent non-target people is probable.
SUMMARY OF THE INVENTION
[0011] It is a primary object of the present invention to provide a
frangible hollow point bullet adapted to be used in conventional
small arms cartridges.
[0012] It is another object of the invention to provide a bullet
meeting the primary objective, set forth above, wherein a shank
portion of the bullet that is suitable for ballistic analysis is
recoverable after impact of the bullet with a target.
[0013] It is a further object of the invention to provide a
frangible hollow point bullet that fragments on impact with a
target and wherein the size of the fragments is substantially
controllable and uniform.
[0014] It is yet a further object of the invention to provide a
frangible bullet that fragments upon impact with a target and
wherein the spatial distribution of bullet fragments is
substantially symmetric through a solid angle centered on the
trajectory of the bullet prior to impact with the target.
[0015] The above objectives of the invention are met by a
substantially bullet-shaped projectile having a leading end, a
trailing end and a frangible body portion therebetween. The
projectile has a hollow cavity opening onto the leading end of the
body portion and extending rearwardly therefrom into the body
portion. In a first preferred embodiment, the hollow cavity
comprises a plurality of coaxial cylindrical cavities, wherein the
diameter of each rearwardly adjacent cylindrical cavity comprising
the hollow cavity decreases stepwise, in discrete increments, in a
direction rearward of said leading end. In the first preferred
embodiment of the projectile, at least one of the cylindrical
cavities has a cavity wall bearing stress risers thereon. In a most
preferred embodiment of the projectile, all of the cylindrical
cavities comprising the hollow cavity have a pattern of stress
risers on the wall thereof. Examples of suitable patterns of stress
risers include a diamond-shaped pattern of grooves, a plurality of
parallel grooves, a plurality of horizontal and or vertical grooves
and so forth. The depth of the hollow cavity relative to the axial
length of the projectile can be varied to control the fragmentation
pattern and the size of the intact, recoverable base or shank. The
inclusion of stress risers within the hollow cavity provides means
for controlling fragment size upon impact. In a second preferred
embodiment of the projectiles, the cavity in the leading end of the
projectile comprises a plurality of concentric conical cavities
having decreasing diameter in the direction of the trailing end of
the projectile. Preferred projectiles include bullets and shotgun
slugs and pellets. In an embodiment of a shotgun slug having a
hollow cavity in the rearward trailing end thereof, the wall of the
hollow cavity includes stress risers thereon. The outer lateral
surface of the projectile is preferably smooth but may be scored to
bear a pattern. In all embodiments, the leading end of the hollow
cavity may be conically flared outwardly.
[0016] The features of the invention believed to be novel are set
forth with particularity in the appended claims. However the
invention itself, both as to organization and method of operation,
together with further objects and advantages thereof may be best
understood by reference to the following description taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a side elevational view of a cartridge comprising
a bullet in accordance with a first embodiment of the present
invention.
[0018] FIG. 2 is a cross-sectional view of the cartridge of FIG. 1
taken along section line 2-2 wherein the cartridge is center
firing.
[0019] FIG. 3 is a cross-sectional view of the cartridge of FIG. 1
taken along section line 2-2 wherein the cartridge is rim
firing.
[0020] FIG. 4 is a cross-sectional view of a frangible hollow point
bullet having two coaxial cavities in accordance with a two-cavity
embodiment of the present invention.
[0021] FIG. 5 is a cross-secional view of a frangible hollow point
bullet having three coaxial cavities in accordance with a
three-cavity embodiment of the present invention.
[0022] FIG. 6 is a cross-sectional view of a three-cavity
embodiment of a frangible, hollow point bullet wherein the walls of
the cavities have been skived to provide a grooved, diamond-like
pattern thereon.
[0023] FIG. 7 is a cross-sectional view of a three-cavity
frangible, hollow point shotgun slug wherein the three cavities
have been skived by a tap to produce a plurality of parallel
slanting grooves on the cavity walls.
[0024] FIG. 8 is a cross-sectional view of a multicavity,
frangible, hollow point bullet illustrating a variety of stress
riser patterns skived on the respective cavity walls.
[0025] FIG. 9 is a cross-secional view of a frangible hollow point
bullet having three coaxial conical cavities in accordance with a
three-conical cavity embodiment of the present invention.
[0026] FIG. 10 is a cross-secional view of a frangible hollow point
bullet having three coaxial conical cavities in accordance with a
three-conical cavity embodiment of the present invention wherein
the walls of the conical cavities are skived.
[0027] FIG. 11 is a cross-sectional view of a frangible hollow
point bullet having three coaxial conical cavities in accordance
with a three-conical cavity embodiment of the present invention
wherein the walls of one or more of the respective conical cavities
are indented.
[0028] FIG. 12 is a cross-sectional view of a wad used to propel
one or more projectiles such as pellets from a shotgun shell
wherein the wad comprises a compressible trailing portion and a
cup-shaped leading portion that is slit.
[0029] FIG. 13 is a cross-sectional view of a wad used to propel
one or more projectiles such as pellets from a shotgun shell
similar to the wad shown in FIG. 12 wherein the wad comprises a
compressible trailing portion and a cup-shaped leading portion that
is only partially slit.
[0030] FIG. 14 is a cross-sectional view of a wad similar to the
wads shown in FIGS. 12 and 13 but wherein the wad comprises a
compressible trailing portion and a cup-shaped leading portion that
is unslit and contains a foam or a gel.
[0031] FIG. 15 is a cross-sectional view of a wad used to propel
one or more projectiles such as pellets from a shotgun shell
wherein the wad comprises a noncompressible trailing portion and a
cup-shaped leading portion that contains compacted particles.
[0032] FIG. 16 is a cross-sectional view of a wad used to propel
one or more projectiles such as pellets from a shotgun shell
wherein the wad comprises a noncompressible trailing portion and a
leading portion that contains a foam or a gel.
[0033] FIG. 17 is a cross-sectional view of a wad used to propel
one or more projectiles such as pellets from a shotgun shell
wherein the wad comprises a noncompressible trailing portion and a
noncompressible, unslit leading portion.
[0034] FIGS. 18-23 are illustrative of the manner in which the
surface morphology of shotgun shell pellets can be modified to
produce different effects prior to, during and after impact with a
target.
[0035] FIG. 24 is a cross-sectional view of a hollow point shotgun
shell projectile or slug wherein an insert within the trailing end
of the projectile comprises one or more straight fins to stabilize
the trajectory of the slug.
[0036] FIG. 25 is a cross-sectional view of a hollow point shotgun
shell projectile wherein an insert within the trailing end of the
projectile comprises one or more angled fins to rotate the
projectile and stabilize the trajectory of the slug.
[0037] FIG. 26 is a cross-sectional view of a hollow point shotgun
shell projectile wherein an insert within the trailing end of the
projectile comprises one or more curved fins to rotate the
projectile and stabilize the trajectory of the slug.
[0038] FIG. 27 is a cross-sectional view of a shotgun shell having
a compressible wad and a plurality of pellets with cavities therein
embedded within a gel or a foam.
[0039] FIG. 28 is a cross-sectional view of a shotgun shell
comprising a compressible wad and a helically finned, hollow point
projectile having a conical double cavity with indentations in a
leading end thereof.
[0040] FIG. 29 is a cross-sectional view of a shotgun shell having
a compressible wad and a plurality of hollow point bullets, with or
without scoring, laterally enclosed in a sabot.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] A cartridge 10 comprising a frangible, three-cavity, hollow
point bullet 11 in accordance with a three-cavity embodiment of the
present invention is shown in side elevational view in FIG. 1. The
cartridge 10 includes a case 12 encasing explosive material for
expelling the bullet 11 from the case 12. The case 12 has a leading
end 13 which houses the bullet 11 and a trailing end 14 housing a
primer 21 (FIG. 2) that explodes upon mechanical impact.
[0042] Turning now to FIG. 2, the cartridge 10 of FIG. 1 is shown
in cross-sectional view, taken along section line 2-2. If the
cartridge 10 is center firing, the primer 21 is axially disposed on
the trailing end 14 of the case 12 as shown. Forward of the primer
is an explosive charge 22 such as gunpowder. A bullet 11 is
pressure fitted into the leading end 13 of the case 12. The bullet
11 has three cylindrical, coaxial cavities in the nose thereof: an
outer cavity 23, a middle cavity 24 and an inner cavity 25, the
respective cavities having progressively smaller diameters. A rim
fire cartridge 30 is shown in cross-sectional view in FIG. 3. The
construction of the cartridge 30 is similar to the cartridge 10 of
FIG. 1 except that primer 21 is incorporated into the trailing end
14 of the case.
[0043] A key feature of all embodiments of the frangible bullet of
the present invention is the presence of more than one coaxial
cavity in the nose of the bullet, such as illustrated, for example,
in FIGS. 4 and 5, and/or the presence of a scored pattern on the
wall of at least one cavity. Prior art hollow point bullets, such
as described earlier, have grooves on the outer surface of the nose
of the bullet to provide controlled mushrooming. The present
inventors have found that for hollow point frangible bullets, the
fragmentation pattern can be controlled by skiving the wall of one
or more of the cavities comprising the hollow point. The skived
pattern may take any of the forms shown in FIGS. 6-8. FIG. 6 shows
a three-cavity embodiment of a frangible, hollow point bullet
having a diamond-shaped pattern skived on the cavity walls. FIG. 7
shows a three-cavity embodiment of a frangible, hollow point slug
70 for a shotgun shell having a diagonal set of parallel grooves
skived on the cavity walls and a diagonal set of parallel grooves
in a rearward cavity 71. FIG. 8 illustrated a four-cavity
embodiment 80 of a frangible, hollow point bullet having a pattern
comprising a plurality of parallel diagonal grooves 81, a plurality
of vertical grooves 82, a plurality of horizontal grooves 83 and a
diamond-shaped pattern 84 skived on the respective cavity walls.
While particular skived patterns are illustrated on the cavity
wall, such patterns are provided for the purpose of example. It is
contemplated that other patterns may also be skived on the wall of
a cavity.
[0044] When drilling, molding, or otherwise creating the cavities
in a frangible bullet of the present invention wherein uniform
fragment size is an important consideration, and the (multiple)
cavities have different diameters and depths, the bore/depth ratio
of the cavity is limited. If the cavities are drilled too deep,
fragment size may be nonuniform, and the accuracy of the bullet is
reduced. The use of multiple cavities in the nose of a bullet, each
cavity having a moderate depth and bore diameter, provides a more
uniform fragment size. In addition, by increasing the number of
cavity sizes employed to create the hollow point, the greater the
effectiveness of the stress risers (i.e., the pattern of grooves on
the cavity walls) for controlling fragmentation of the bullet.
Bullet stability (accuracy) can be adversely affected by an
excessive number of cavities in order to minimize the size of the
residual base or shank. Reduction of the residual base (shank) to a
minimum mass (even to zero) can be achieved with multiple diameter
holes, however a loss of bullet accuracy may occur. The inclusion
of stress risers on the interior wall of the cavity(ies) of a
frangible bullet in accordance with the present invention, by
scoring, forming or skiving a pattern of grooves thereon, or
forming a pattern of indented "dimples" thereon greatly enhance the
uniformity of fragment size upon impact. The leading end of the
hollow cavity may be conically flared. A hollow point projectile
having a hollow, axially symetric cavity that comprises three
cylindrical cavities with decreasing bore diameters, that include
stress risers on the cavity walls, provides a controllable breakup
pattern as desired. Since the fragmentation of a frangible,
multicavity hollow point bullet in accordance with the present
invention will not substantially extend rearwardly of the axial
cavity, the residual mass of the base (shank) can be determined by
the total depth of the cavity.
[0045] The embodiments of a frangible bullet described herein
allows consistent and controllable performance as to penetration,
frangibility, and fragment size and shape for hollow point bullets
comprised of various materials at sub-sonic, sonic, and super-sonic
velocities and in various ammunition types. The frangible
bullet/projectile in accordance with the present invention may
comprise, but is not limited to any sintered, unsintered, cold
compacted, cast, or cured bullets. Frangible, hollow point bullets
in accordance with the present invention have an axially symmetric
hollow cavity comprising a pattern of intersecting (diamond
pattern) and/or non-intersecting stress risers skived or otherwise
formed on the cavity wall. The shape of the nose cavity and pattern
of the stress risers can be used to pre-determine fragment size,
fragmentation pattern and action. In addition, the leading end of
the hollow cavity may be conically flared without departing from
the scope of the present invention.
[0046] With reference now to FIGS. 9-11, a bullet 11 having a
plurality of conical cavities in a leading end thereof is
illustrated in cross-sectional view. FIG. 9 illustrates a bullet 11
having two coaxial conical cavities 90 and 91 in the leading end
thereof. The innermost cavity 90 has a smaller outer diameter than
the outermost cavity 91 with a step 94 therebetween. The advantage
of hollow point bullets having conical recesses therein is that the
cavities 90 and 91, as well as the flared leading edge 92, can be
easily molded into the bullet during the manufacturing process. The
walls 93 of the cavities 90 and 91 are smooth in FIG. 9, skived 100
in FIG. 10, or may bear a pattern of indentations as shown at 110
in FIG. 11. The skiving 100 and indentations 110 can be formed in
the wall of cavities 90 and 91 by molding (the skived pattern) or
by forcing a conical scoring tool thereinto (indentations).
[0047] When constructing shotgun shells, a thickness of wadding
material is normally interposed between the projectile(s) and the
powder propellant. Some examples of a suitable wadding material in
accordance with a further aspect of the present invention are
illustrated in cross-sectional view at numeral 120 in FIGS. 12-17.
With reference to FIG. 12, a thickness of wadding 120 comprises a
compressible portion 121 housed within a substantially
noncompressible cup portion 122. The noncompressible cup portion,
usually plastic, may have at least one slit 123 therein to permit
the cup-shaped leading portion of the wad to open when it is
ejected from the shell, thereby increasing its cross-sectional area
and slowing it down to lag behind the projectile(s) (not shown in
FIGS. 12-17) housed therewithin after the wad leaves the barrel of
a shotgun. The depth of the slit 123 as well as the number of slits
may be varied in order to control the pattern of pellets propelled
from the shotgun shell. An example of a wadding 120 that comprises
a compressible portion 121 and a noncompressible cup portion 122
that has partial slit(s) 123 therein is illustrated in
cross-sectional view in FIG. 13, and a shotgun shell having an
unslit noncompressible cup portion filled with a foam or gel 163
and a compressible portion 121 is shown in FIG. 14.
[0048] The wad 120 may also comprise a noncompressible portion 151
and a noncompressible cup-shaped portion 122 as shown in FIGS.
15-17. The pellets 152 may be packed in the noncompressible
cup-shaped portion 122 with a particle buffer 153 or a foam or gel
buffer 163 therebetween as shown in FIG. 16, or with no buffer
therebetween as shown in FIG. 17. For clarity, the pellets are not
shown in FIGS. 12-17. As with the previous embodiments of a wad
shown in FIGS. 12-14, the cup portion 122 may be slit, partially
slit or unslit, depending on the application.
[0049] Examples of frangible pellets that are suitable for use as
projectiles that can be housed within the noncompressible cup
portion 122 of a shotgun shell are shown in plan view in FIGS.
18-23. A pellet having a plurality of dimples 180 in the surface
thereof is shown in FIG. 18. FIG. 19 shows a pellet having three
orthogonal bores 190 drilled therethrough. FIG. 20 shows a pellet
having a plurality of conical cavities 200 in the surface thereof.
The wall of the cavities 200 may be smooth, skived or bear
indentations thereon. A pellet having two orthogonal
circumferential grooves 210 on the surface thereof is illustrated
in FIG. 21. FIG. 22 shows a pellet having an outer surface bearing
a pattern such as polygons 220 or similar geometric patterns. A
pellet having a plurality of cylindrical cavities 230 in the
surface thereof is illustrated in FIG. 23. Again, as with the
pellet shown in FIG. 20, the wall of the cavities can be smooth,
skived or bear indentations thereon. Such modifications of the
pellet surface as, for example, shown in FIGS. 18-23, can be used
to alter the aerodynamic behavior of the pellet(s) and/or serve as
stress risers to establish a predetermined pattern of
disintegration of the pellet(s) upon impact with a target.
[0050] The aerodynamic behavior of hollow point projectiles such as
the shotgun slug 240 illustrated in FIG. 24, or the solid-nosed
shotgun slugs 250 illustrated in cross-sectional view in FIGS. 25
and 26, may be modified by the addition of fins to the trailing end
thereof. With reference now to FIG. 24, a hollow point shotgun slug
240 has a pair of conical cavities 91 and 90 coaxially disposed on
a leading end of a body 245 and an insert 241 affixed to a cavity
242 in a trailing end of the body 245 by means of an adhesive 243.
The trailing end of the insert 241 has a plurality of fins 244
projecting rearwardly therefrom that serve to stabilize the
trajectory of the slug 240 through the air. A solid-point slug is
indicated at 250 in FIG. 25 having an insert 241 that screws into
the cavity 242, a thread 251 providing means for attaching the
insert 241 to the body 245 of the slug 250. The insert 241 has a
plurality of tilted fins projecting rearwardly therefrom to impart
rotary motion to the slug 250. FIG. 26 shows a slug similar to the
slug illustrated in FIG. 25 but wherein the fins 262 are helical
and project rearwardly from the slug to impart rotary motion
thereto when propelled through the air. The insert is attached to
the body 245 by means of a "C-ring" or hog ring 261 that fits
within an annular groove 260 in the body 245. It will be understood
and appreciated by the artisan that finned inserts can be used with
either hollow point or solid point bullets and that various methods
may be used to attach the fins to the body of the slug.
[0051] An example of a shotgun shell 270 comprising a plurality of
pellets such as plain spherical pellets or the novel pellets
illustrated in FIGS. 18-23 is shown in cross-sectional view in FIG.
27. The shotgun shell 270 comprises a case 271 having a base 272
that supports an impact-ignitable primer 273. A charge of explosive
274 is disposed between the primer 273 and a compressible wad 275.
A plurality of pellets 276 embedded in a foam or a gel 277 is
disposed between the wad 275 and the leading end of the case 271. A
further example of a shotgun shell in accordance with the present
invention is indicated at numeral 280 in FIG. 28. As with the
shotgun shell 270, discussed above, the shotgun shell 280 comprises
a case 271 having a trailing end 272 that supports a primer 273,
and houses an explosive charge 274 and a wad 275. A hollow point
slug having double conical cavities 90 and 91 in a leading end
thereof is disposed between the wad 275 and the open leading end of
the case. The slug 281 has a finned insert 241 affixed via threads
to a cavity in the trailing end of the slug. The helical fins 262
cause the slug 281 to spin when fired.
[0052] A further application of the frangible, hollow point
projectiles of the present invention is illustrated in FIG. 29.
FIG. 29 is a cross-sectional view of a shotgun shell 290 having a
wad 120 comprising a compressible portion 121, a noncompressible
cylindrical sabot 293 and a plurality of hollow point slugs 294 and
295 bounded laterally by the sabot 293 within the shell 290. The
sabot 293 is a tubular sleeve, usually plastic, having a slit 297
coextensive with the length thereof and an axial bore 296 equal to
the outer diameter of the slugs or bullets 294 and 295. The sabot
enables small diameter projectiles to be fired from a gun having a
larger bore.
[0053] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. For example, the lateral outer surface of any of the
frangible, hollow point projectiles disclosed herein may be scored
or otherwise patterned. It is therefore intended to cover in the
appended claims all such changes and modifications that are within
the scope of this invention.
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