US2333091A - Expanding projectile - Google Patents

Description

Nov. 2, 1943. v. N. CRASNOFF EXPANDING PROJECTILE Filed March 29, 1940 INVENTOR vncroa N. CRASNOFF BY 5". W

ATTORNEY Patented Nov. 2, 1943 Cartridge Company, East Alton,'lll.. a corporation of Delaware Application Maren 29, 1940, Serial Nemesis.

12 Claims. This invenion relates to projectiles of the ex panding or-mushroomtype and in particular to projectiles adapted for use in high power rifles.

Expanding or mushroom projectiles are generally constructed with a core of lead, or other soft metal, and are designed to deform by spreading out or flattening in the forward portion when they encounter the resistanceoffered by the objective, thus increasing'the effective-"area and destructive action of the projectile. Projectiles of this type are most effective when such deformation occurs within the objective itself,

since less effective wounds generally result when the expansion occurs immediately upon impact, causing a superficial injury, or when the projectile passes through the objective without expanding. I v

Such projectiles are usually known as point, when the rear portion of the soft metal core is covered by a hard metal jacket andthe soft metal forming the nose of-the projectile'is left exposed, or as hollow point, when the nose of the projectile is hollow, slit, or similarly weakened. In order to prevent deformation of the exposed soft core metal in the handling incident to manufacture and use, some expanding projectiles have been provided with tip jackets; Such tip jackets have been so constructed as to avoid any delay in the mushrooming action of the increased resistance to deformation, brought about by such expedients as providing soft poin bullets with only a small exposure of the soft metal in the nose, or "hollow point bullets with only a small opening in the nose, or pro-- viding soft-cored projectiles with non-expandible tip jackets, belts, and the like, orlby increasing the hardness of the core material.

However, bullets of such prior construction all have in common the disadvantage that for each given construction, the range of effective impact velocities is rather small, and consequently, the

range of effective shooting distances is likewise small, Since the impact velocity varies with the shooting distance.

This is indeed a serious disadvantage since it is now possible with high velocity ammunitionand improved sighting equipment, to shoot acsoft curately with the high 'power rifles over a range: of distances much greater than the range in which such-projectiles are effective. A given projectile of such prior construction, designedto expand at certainimpact velocities will pass through the objective without expanding at appreciably lower impact velocities, thus expending only a small portion of the stored-up energy within the'ob jective itself,- or at appreciably higherimpa'c-t velocities the projectile will expand too quickly, thus expending a greater part of the stored-up en'ergyin the formation of a superficial wound" without penetrating into the Vitals of the ob J'ective. T

A further disadvantage'with projectiles of such prior construction is that when the projectile strikes atwig, small tree branch, or similar accidental minorl resistance in its trajectory,it ex pands or disintegrates and, as a res'ultgfails. either to reach or penetrate the target. Conse} quently, 'the shooter is very much handicapped in shooting throughbrush, thickets, or'the like.

One of'the objects of this'invention, therefore,

is to provide an expanding or mushroom projectile so constructed as to be effective over the entire range of distances in which it is possible to's'hoo't accurately with the modern rifle; Another object of' this invention istoprovide an expanding or mushroom projectile so constructed as to temporarily delay the spreading or expanding action at'the time of impact with. the objective. ff

' Another object is toprovide such apr'ojectile having a doubl jacket constructed and arranged tofa'cilitate' the rapid expansion of the forward portion or the point of the projectile'after the complete entry of the proj ectileinto the objective. Another object is to provide such a projectile efiectiveover a wide range of impact-velocities, that is, effective overa wide range of shooting t "j T'j Another object -is'to provide such a projectile which, although having a soft core, is provided with a tip that is resistant to defo-rmatiofi when subjected to the usual handling incident {to inanufactureand use, or when striking an accidental minor obstruction in its fiightto the-target} Further objects will-appear from thede'scrip' tion,taken in connection with i drawing, in 'which 'Figures' 1, 2, and 3 aresidewiews partly in section of certain'projectilesembodying th'i'sin vention;

Figure 4 isa side view partly in section-show ing" the form taken-by the projjectileafter impact.

the wer e.

In accordance with this invention, projectiles having the desired characteristics of expanding properly to mushroom shape at high impact velocity and likewise over a wide range of impact velocities, are secured by enclosing a soft metal core in a novel type of double jacket. An envelope or tip jacket of suitably hard resilient metal covers the forward portion of, the core, whilea second jacket, which is relatively strong,v covers the base of the projectile, extends over the envelope and covers all but the forward portion or, nose of the projectile.

The function of the tip jacket is to provide a decreased rate of, or temporary delayin, thev expansion of the-core on impact with theobf jective. This is accomplished" by virtue of'the strength and resilience of the envelope and by the fact that the two jackets are so'joiried -or.

interlocked as to prevent a separation of the, tip jacket from the base jacket upon impact with theobjective. Although thepoint of the projec tile isgradually deformed or bulged out inpenetratingthe objective, the jackets do not separate. upon impact, and actual mushrooming, doesnot occur until sufficient pressure has been built upv in the underlying core, due to the resistanceem,

countered, to rupture the tipjacket on the no sea ofthe projectile. Thereupomthe core material. rapidlyspreads out to give the desired mushroom shape.

Satisfactory mushrooming action is accomplished atboth high and lowimpact velocity, since a period of penetration is :provided during; which sufficient pressure builds up in the;1 cO1.'e to rupture thetip jacket and after the tip jacket is ruptured, a large portion of the soft core is exposed so that the projectile is mushroomed even at relatively low impact velocity. Th base jacket, because of its relative rigidity, limits the degree to which the projectile expands. However, in the process of mushrooming, the front end of the base jacket is rolled backinto a curl toform a supporting shoulder for the expanded soft core metaL- Referring to the accompanying drawingand, more particularly to Figures 1, 2,'and .3, aprojectile embodying this invention is adapted for: usein high power rifles and, accordinglygmay have any desired suitable profile or shape, :such asconoidal, ogivaLblunt, round, pointed, orsemi pointed, but has the construction hereinafter de-' scribed. I p

The core 6, preferably having a narrowed; or tapered-forward portion, may be formed o fgany suitable material, such as lead, lead a1 loy, or material capable ofsdeformation in a imilar manner., ,The tip jacket 1 covers the forward portion of the core ,6 and extendsfrom the point 9 toward and preferably to within less than a caliber of the base [0, or, if desired, it may exten dpontothe base H), or may even completely cover the, core. This tip jacket is formed of material harderthan the core, such as drawn copper, copper alloy, or othermaterial having suitable resilience and, hardness, and is of sufiicient strengthto delay expansion upon impact with the objective, even though the core, being of lead or like-ma terial, is soft and malleable.

The base jacket 8 covers the base IE]v andrearportion of the projectile, overlaps the tip jacket, 1 and extends forward preferably to the narrowed portion of the tip jacket, a large'portion of the tip jacket remaining exposed. The base jacket? isformed of copper, copper alloy, or other. suitable. hard ,resilientinaterial; The; ba jacket 5+ preferably extended only just past the point where "the projectile starts to narrow in the forward ."portion, so. that a relatively large portion of the tip, jacket is left exposed. '.-jacketj,shoul d".bethick and hard enough and shouldIextend'sufiiciently forward to prevent the However, the base exposed 'tip jacket from engaging, or coming in contact withIthe rifling of the gun bar-rel.

,l'norderto obtain the desired delay in expansion and" to prevent the projectile from mushrooming too1quickly. as ,a :result; of a, separation ofltheptwo; jackets ,upon impactqat high lvelocity,

thetip 'jacketis extended underthehbase jacket almost to theebase of the core -and;,uas;stated above, may even overlap the base or, ,:completely, cover the-core. -How.ever;a somewhatshorter tip jacketgmay-be .used if some equivalentmeans of joining;or interlocking the tipjacketto the base jacket, for instance bys soldering, Welding, and

the like, is employed-to prevent :them from separating upon impact.

'The thicknessof the; two jacketsmaybe varied in which itis required that theprojectile beeffective, the weight of the projectile, the surfaceof tip jacketexposed, the profile of the projectile, andthe material from ,which the jackets are formed.- For instance; thinner tip jackets may be employed when operating over a .range of low impactyelocities, orgwhen atsmaller surfac jof the: tip jacket is exposed, ,ori when the noseof thetprojectile ,is more -pointed; Likewise,- as the weight. of the projecti -l eis increased ,and the, hardness and resilience? of thematerial from whichthe jackets ,are made glS decreased ,thicker jackets 'maybe employed.

,Some of these variables may be changed so as tohave a compensating-effect, thus not requiring, anychange-inthe thicknesspf the jackets; For

example, in practice, instead of increasing the thickness of the jackets, when the weight or velocity of the projectile is to be increased, the sameresult may usually be accomplished by changing the profile, since a thinner tip-jacket maybe employed ,witha-more" pointed profile.

Euiither, it isnot essential that'the jackets, be

of u ni form thickness. throughoutg- For instance, it may be desirablein some cases tohave the-tip jack t t k r o th a a d ort of. t e nos thanron the body of lthe-projectilegan dt thevbasetjacket maybe th-inner in the-forward QOl'tiQIlr than it islat th efbase of-itheprojectile:

. lnxl v l 35 thQ-wfi bl .5 4 11 13 2 .slil l ld i be thick enough andhavesufiicient strength and toughness to prevent splitting and: tearing ofthe tive.

proj ectilebefore the jacket itself is; split.

In order to illustrate a specificembojdiment of the inventiom following is a detailed description f a- 390 B :8 H Ma num 0 era ml t wh ch" s? been eu isito hav ntirel sat sf tory mushrooming characteristics. A rough lead 'slug formed-soffcopper or copper alloy; in' order to cast in a mold was swaged with a punch and die to the profile and weight desired to form the core. The tip jacket was formed by punching a cup from a metal sheet of copper alloy, composed of about 72% copper, 18% nickel, 9.25% zinc, and 0.75% manganese. The "cup was then drawn in several stages with suitable intermediate annealing to a sidewall thickness of about 0.0075 inch,

and a bottom thickness of about 0.020 inch. After the last drawing step, the cup was trimmed to the desired length so as to cover the core almost to the base and it was then annealed. to an average grain size of 0.02-0.04 mm. The swaged lead core was then assembled in the drawn tip jacket and the assembly pressed in a die to the desired shape.

The base jacket was formed by punching a cup from a metal sheet of copper alloy composed of about 90% copper, 9.25% zinc, and 0.75% tin, and the cup was then drawn in several stages, with suitable intermediate annealing, to a thickness of about 0.030 inch. In the last drawing step the cup was chamfered at the mouth and then trimmed. The assembled core and tip jacket were then inserted in the base jacket and the assembly was pressed in a die to impart the desired profile to the projectile.

The base jacket was then cannelured, thus providing the projectile with two separately spaced circumferential grooves extended into the thin jacket and core in that portion of the projectile in which the base jacket and tip jacket overlap. As a final operation, the projectile was then sized to insure uniformity of diameter by passing it through a die. The assembled projectile was approximately 1% inches long, the base jacket extending up the projectile for of an inch. The exposed portion of the tip jacket was a;- of an inch long, the tip being finished with a fiat portion about %6 of an inch in diameter.

It should be noted that the tip jacket is rela tively thin having a wall thickness substantially less than 0.020 of an inch and that the base jacket having a thickness greater than 0.020 of an inch is substantially thicker than the tip jacket. Further, the base jacket overlaps the tip jacket, covering a large portion of the soft core with two jackets of relatively hard material while leaving a large portion of the tip jacket exposed. The projectile provided is of relatively simple construction and can be manufactured with little difificulty at low cost. r

The effect and performance of the projectile are outstanding indeed. Referring to Figure 4,

which shows a side viewpartly in section of the projectile of Figures 1, 2 and 3 after having been fired into a relatively soft objective, such as the flesh of an animal, at an impact velocity of 2500 feet per second, it will be seen that the rear portion of the projectile is substantially unchanged,

whereas, the forward portion of the'core 6 has. been spread out substantially without disintegration into the shape of a mushroom similar to that assumed by the usual soft nosed bullet when fired at low velocity.

Due to the effect of the double jacket there is a tendency for the base jacket 8 to rollback without'splitting from the open end 13 into a curl which forms a supporting shoulder for the xpanded core. Such rolling action, which is not obtained with the usual jacketed mushroom bullet, is facilitated by providing a chamfer at the open end 13 of the basejacket, or, for instance,

by annealing the jacket at this point,- if it is soften the metal.- JIn theusual mushrooming b'ullet the base jacket splits into strips whichare turn away from the "projectile, thus leading to excessive disintegration-of the bullet and making it less effective. Generally a smaller percentage .1 of the weight of theprojectile of thisjinvention. is lost after impactthan' is the case. with 'the usual soft point or mushrooming bullet in which thebase jacketsplits or is detached from the core upon impact with the objective. r

In'contrast to expanding projectiles of prior construction designed for 'use in high-i-velocity ammunition, in which the means employed for aiding penetration offers a more or less permanent resistance to expansion of the projectile, the projectile provided herein gives the desired penetration but the means employed forresisting ex: pansion is'only temporarily effective, the delay in expansion being terminated by the bursting of the tip jacket,.so that thereafter the projectile is rapidly deformed to mushroom shape.- 3

Thus, the projectile provides the advantages" of a soft point bullet having a large area of the soft core exposed, without the attending disadvantages. The delayed expansion orreduced rate of expansion depends on the retention of thesoft core material within the jacketsuntil the tip jacket is ruptured or split." When the projectile is fired into a relatively soft" objective, such'as' a game animal, the relatively thin tipi-jacket delays expansion until. the projectilebas -penetrated through the thick hide and muscle tissueg" Dur ingisuch penetration the internal pressure from the gradually compressed core causes the nose of the projectile to bulge out or swell. l-Ioweizerf. since such projectiles are usually narrowed, or:- tapered, in the forward portion, such bulging 'of th tip jacket does not appreciably increasethe original diameter of. the projectile andconsequently. the projectile. does not lose 'muchio'fJits. energy for about thefirs't two inches, or so,; of penetration. Howeveryias' the internal 'pressure' from the, compressed core material is increased, the tip jacket is ruptured, the soft core mate.- rial' rapidly spreads Iout and the projectile. assumes the desired mushroornf shape,. thereby greatly increasing its effective area. Thus, the greaterpart of the energy stored .up in the projectile is utilized while the projectile is in its expanded form inthe interior of. .the .objective... Asthe projectile expands, the pressure; transmitted to the base jacket causes the latter to curl back .at the rim,'thus forming a strong, supporting shoulder for the expanded portion of the; soft core materiahand greatlyinereasing the destructive action of the projectile. Theexposure of a large portion of the soft core, after the tip jacket has been ruptured, causes theforward portion to expand even at low velocity in a mannervery similar to that of the usual soft' nose bullet At'both high and low velocity, however, the degree of expansion is limited so that the, bullet is deformed to mushroom shape. For instance,the projectile described in the specific example above, when fired into a relatively soft objective, has been found to give eifective mushrooming action at impact velocities'ranging from This invention accordingly provides expanding I projectiles of simple and sturdy construction, so designed as to display effective mushrooming action, within thebody cavity, after penetration of the;present invention as shown-and ,describedarer 10 only illustrative; and that-thescope of theinventionz is' not to be limited therebyexcept insofar; asiis defined. in the-following claims.

Having; thus describedl the-inventionwhat: tisclaimedds:

'1. expanding projectile comprising a; coreof so,ft metal; a-thin hardzmetaltipwjacketicovering; the :forward end ofsaid: core :and; extended thereon toward the-base of thegprojectile, said:

tip jacket having its entire-inner surface ;in:c,on-;- 2g;

tact with said coreand adapted,;to*-delay3 ex pansion of said corecuntil:thexprojectileihaapenetra-ted theobjective, and a hard-:metalbaseyjacket thicker than the, tip acket .coveringithe' i'basernf:

the; projectile; and overlapping onrsaid' tips-jacket, 257

and extended over a major :part but ,notathe whole length of the core, said jackets Tbeingyiniterlocked and adapted thereby vto preventz'the tip 1 jacket from separating from the'base 'jacketqupon impact.withzthe'objective.

2.An expanding projectileiicomprisingr-a core: of "soft metal, -'a thin chard metal ,tip 'jacketl cov ering said core, said :tip jacket :havingrits-entire inner surface in contact Withsaidzcore:andzadapte ed to delay expansion of 'said core iuntil :the: J

projectile has penetrated therobjective andia h'artl'; metal base jacket thicker ;than;;the tiprjacketz covering the base of the projectile andjovere lapping on said tip jacketand extended. overea: major :part'but not the whole :length ;of .therzore; said ijackets being interlocked and radaptedtthereiby to prevent thetip jacket from'separating;from* the base jacket uponiimpactxwith the objective;

'3. 'An expanding projectileacomprisingw core of soft metal, a thin hard metal tipijacket cover ing the forward "end :01 saidxcore and extended: thereon toward the base of the. :projectile; said; tip jacket being completely "filled 1byrsaid;-;core and adapted to delay expansion :of said .coreuntil the projectile has penetrated thezobjectiverand I: a hard metal base jacket'i thicker? thani'the tip" jacket .coveringthe baseaofi the iproj;ectilewandi overlapping on said .tipijacket and extenddinver: asmajorpart but not the 'wholel length' ofzthe core and provided with at'least one-circurnferen tial groove, said jackets 'being-interlocked and adapted thereby to prevent thetip jacket fromi separating from the base jacketfon impact with the-objective.

4; An expanding projectile comprising :a' core" of soft metahathin hard metal tip jacket"'cover.+'- ing the forward end ofsaid core and 'I'extended 1' thereon toward the'b'ase of th'e projectile, said? tip jacket having its entire inner-surfacein contact with said core and adapted to delay-expansion of said core until'the projectile has -pene trated the objective, and a 'hardmetaljfbase jacket thicker than the tip jacket 'covering the base of the projectile and overlapping on :said tip jacket and extended over a ;major,p art but. not the whole length of @the core, and.,proyided" with indentations extended intov the... tip ja,ck'e.t core, said jackets beingginterlocked ,and adapted. thereby-to prevent; .the tip jacket af -rpm separatingiiromai the:;base jacketi unonpimpact with the objective;

- 51.2 An; expanding; proj ectilezhaving 1ainarrowed forwardmortion: compriisng-ia .core ;of:'soft.-metal, a thinvhardnmetal tipijackettooveringthe forward .endaofjsaid core, and extended l thereon towardzthe-l base :of; the zprojectile, said tip, jacket beingzcompletelyxfilledabyrsaicl core and :adaptedto: delay iexpan'sio'n ,of isaidficore: :until; the :PIO-

j ec tile has. :penetratedu the; objective 'and'ia :hard: metaltzbase ajacket" thicker 'thanrcthetip r jacket covering the basecofzthe projectile and overlapping on ."said tip-jacket and extended on .1 to :the said J narrowed laportion .of .the p'rojectilewleaving a .;large portion 'of said tiptj acket: on" said core.

exposed: 'said- 'jackets being: interlocked. :and adapted thereby to preventztheatiprjacket:from separating from-(the base-jacket upon' impact .with the objective.

:6; Anrexpandingzprojzectile comprisingjia ,core substantially oi lead;,;a; think? copper alloy tip jacket. covering .thE'ifOIWEHfdLEIId10f said 1 core; and:extended "thereon towardtl'ieibase of the projectile, sai'dttipijacket.having its entire'inner' surface, in contact "withi said :;core andtadapted to delay expansion flofzisaid .core 'unti1;.thewprojectile has penetrated :theiobjective' and' a' copper alloy base jacket thickerfithan the "tip jacket covering the'base ofiithe projectileend overlapping on saiclfitipxjacket"and extended'. over a,

major part but notithe cwholelengthrof the 'core, said jackets: being interlocked and' adapted thereby to prevent 'thextip jacket from separating from thebase jacketlupon impact .With the objective.

expanding projectile 'comprising' a core of soft metal;a coppertalloytip jackethavingia thickness less than 0.02 inch covering-the -for:

ward "end of said core "and extended :thereon tosaid core'and adapted to delay expansion' ofisaid core until the v projectile has penetrated rithe 1 objective, and ahard metal base jacket covering the base of'the projectile and-overlapping.on said,

tip jacket 'and extended-over. a major part but not'the whole length of the core, said jacketsbei-ng interlocked-and adapted thereby to -prevent thetip jacketirom separating from the base j acketupon' impactrw'ith" the objective;

8. An expanding-projectile comprising acore substantially of l'ea'd; a tip jacket'substantially of copper having a thickness 0f-1ess than:0.02inch coveringthe forward end of-saidcoreand extendedthereon towards the base'of the projectile,

said tipjacket beingcompletely filled by said core andradapted to delay expansion of said' core until the projectile has penetrated the 1 objective, and "a base j acket substantially I of copper having athickness'greater than '0;02-inch covering the base of "the-projectile and overlapping on-said tip jacket and extended over -a "major part but 'not the whole length of 'thecore; said 'jack'etsbeing 1 interlocked'andadapted to prevent-the-tip jacket from separating "from "the base :jacket uponimhaving: itsentire, inner surface in pcontact "with said core; and adapted .to delay expansion .of said core ,=unt1l 1 the fproj ectile+has penetrated the lob-- ing'thereon toward the base of the core and adapted to delay expansion of said core and a1 copper alloy, base jacket having a thickness greater than 0.02 inch overlapping onsaid-tip; jacketvthe front end of the base jacket being- I provided with a, cha'mfer and terminated to ex 7 pose a portion of saidtip jacket on said core.

jective and a hard metal base jacket havingva thickness greater than 0.02 inch coveringthe base of the projectile and overlappinglon said tip jacket and extended over a major part but ing interlocked and adapted thereby to prevent] not the whole length ofthe core, said Jackets bethe tip jacket from separating from the base jacket upon impact with the objective.

10. An expanding projectile havinga narrowed it a forward portion comprising a soft metal core, a hard metal-tip jacket having a thickness of less than 0.02 inch filled by said core and extending,

thereon to at least within a caliber of the base of the core and a hard metalbase jackethaving a thickness greater than 0.02 inch overlapping on said tip jacket and extending forward onto a the narrowed portion of said tip jacket leaving jacket on said core a large portion of said tip exposed. V I

11. An expanding projectile comprising avcore substantially of lead, a copper alloy tip jacket;

having a thickness less than 0.02 inch extend-.

12, An, expanding projectilecapable of delayed i expansion over a wide rangeofiimpact velocities comprising a soft metal'{core,- a copper alloy tip jacket having athickness less;'than; 0.02,inchv, filled by said .core and adapted 'to delay expans sion thereof and a hard inetalbase jacket cover ing the base of the projectile and overlapping; 1 on saidtipfjacket andadapted tolimit thejde-j gree of said expansion off'said core and engage; the riflingof 'thegun barrel said jackets being; interlocked to prevent thetip jacket from separating from the base jacket upon impact with the objective. v o

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