US2834255A - Recoilless firearm and ammunition therefor - Google Patents

Description

May 13, 1958 c w. MUSSER '2,334,255

REcoILLEss FIREARM AND AMMUNITION THEREFOR Filed Aug. 27, 1952 ATTORNEYS1 RECOILLESS FIREARM AND AIVIMUNITION TIEREFOR C Walton Musser, Philadelphia, Pa., assigner to the United States of America as represented by the Secretary of the Army Application August 27, 1952, Serial No. 306,743

1 Claim. (Cl. 89--1.7)

(Granted under Title 35, U. S. Code (1952), sec. 265) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

yMy invention relates to recoilless firearms `(i. e., rearms in which the recoil forces incident to tiring are neutralized by substantially simultaneously occurring counterforces derived from gas pressures `also incident to firing) and to ammunition especially associated and cofunctioning therewith.

In speaking of recoil forces incident to firing, I make reference to the rearwardly acting recoil forces, of such strength as to warrant counteraction, exerting their inuence, largely, along the axis of the rearms barrel and causing the barrel to kick back (i. e., move in a direction opposite that taken by the projectile); and I make reference, also, to the rotationally acting recoil forces, of such strength as to warrant ccunteraction, exerting their influence, largely, as a torque on the firearms barrel and tending to cause the barrel to rotate about its axis in a direction opposite that of the spinning projectile.

Those skilled in the art knowithat yrearwardly acting recoil forces of suflicient magnitude to lwarrant counteraction are found in both smooth and ried bore iirearms of large caliber, and that the rotationally acting recoil forces of sufficient magnitude to `warrant counteraction are found in rifled bore firearms of large caliber.

Therefore, with reference to smooth bore firearms, my invention pertains to the neutralization of the rearwardly acting recoil forces incident to firing by means of a forwardly acting counterforce derived from the gas pressures also incident to firing and occurring .substantially simultaneously therewith; and, with reference to ried bore firearms, my invention pertains to the neutralization of both the rearwardly acting and the rotationally acting recoil forces incident to vfiring by means of forwardly acting and contra-rotationally acting counterforces, respectively, derived from gas pressures also incident to firing 'and occurring `substantially simultaneously therewith.

An inspection of the prior art will disclose many various ways which have been devised to neutralize undesirable recoil forces. That information is well known to those skilled in the art and, therefore, need not be discussed at length here. Although many of the means heretofore provided have been more or less successful, no one has sought to neutralize recoil forces in the manner I am about to disclose. Therefore, the many later to be mentioned benefits and advantages attending the manufacture and use of my invention previously have neither been known nor enjoyed.

Essentially, my novel recoilless firearm is distinguishable from analogous prior art devices by my combination of an ammunition round having an imperforate cartridge case, a plurality of openings in the gun barrels wall, and an axially extending, annular venturi passage surrounding the rear portion of the rearms barrel. The ammunition round is distinguishable from prior art ammunition rounds A2,334,255 Patented May 13, 1958 by the means I have provided for securing the ammunition round in the firearm.

In practicing -my invention, I provide a gun tube having a slender, relatively thin-walled, forward barrel portion which blends into a somewhat larger diametered, relatively thicker-walled, concentric rear chamber portion. This chamber portion is adapted to accommodate the cartridge case of the ammunition round, while the barrel portion accommodates the rounds projectile.

Secured -coaxially to the barrels rear portion, just ahead of its coniuence with the chambers forward portion, is a recoil neutralizing'sleeve. This sleeve is provided, interiorly, with an axially extending conical opening which tapers outwardly from front to rear. At the forward or smaller end of this opening there also is axially extending a concentric, but somewhat larger diametered recess conveniently shaped for maximum operating eiiiciency.

It will be noted that the interior surface of the sleeves conical opening and the recess adjacent the openings smaller end, in conjunction with the exterior surfaces of the chamber and barrel, form an axially extending, annular venturi passage completely surrounding the chamber. The smaller diametered end of the sleeves conical opening substantially radially opposes the junction of the barrel and chamber to form the venturis throat, or constricted portion. The sleeves shaped recess adjacent the conical openings smaller diametered end and part of the barrel form the input portion of the venturi (i. e., in front of the throat); and the sleeves conical opening and the outer surface of the chamber form the output portion of the venturi (i. e., to the rear of the throat). Because of the way in which the recoil neutralizing sleeve and the barrel are joined, the venturis input portion is closed to the atmosphere, but its output portion is open to the atmosphere.

Eiecting communication between the barrels bore and the forward, input portion of the venturi are a plurality of openings. These openings are located in the Wall of the barrel immediately in front of its junction with the chamber. With the ammunition round in place within the chamber, these openings are commencing substantially on a line `with or just slightly forward of the cartridge cases neck end so that all gases issuing from the case upon ignition of the powder therein `will `exit therethrough and rearwardly substantially simultaneously 4with the forward movement of the projectile.

Although it is possible, by the addition of a breech block, to adapt the barrel of my recoilless firearm to accommodate ammunition rounds having imperforate cartridge cases of conventional design, I find that the merits of my recoilless firearm can be further enhanced by the use therewith of the ammunition round l have'especially provided.

In this novel ammunition round, the cartridge case is provided with a plurality of radially projecting lugs which are intended to engage a corresponding number of :similarly shaped and spaced lugs located inside the firearms barrel. The ammunition round is secured in the barrel by inserting the round, then turning it so that the ycartridge cases lugs and the barrels lugs interlock to prevent the Acartridge cases rearward axial displacement relative tothe gun when the round is fired. After firing, the cartridge case remaining in the barrel is removed by reversing the process.

Relative to a smooth bore firearm, when the ammunition round is fired the force generated by the exploded propellent, in addition to ejecting the projectile, causes a rearwardly acting recoil force tending to displace' the barrel in a rearward direction. However, with my invenf munition roundris fired, the force generated by the exploded'fpropellent," inaddition to ejecting. the projectile,

causesfa rearwardly acting recoil force as before, and

theprojectile in'traversing the lengthrof the ried bore induces a rotationally'acting recoil force. Both recoil forces; however; are eifectively neutralized throughthe operation'of'my invention. Y

Because ofthe' ininitesimally small time interval between `theA actionA of the recoil force, or forces, as the casemay be, andthe action of the recoil neutralizingv counterforce or'V counterforces, respectively, those two actions can be considered as action and reaction, respectively; occurring simultaneously in direct opposition. By properly balancing, the existing recoil (or action) and the required counteraction (or reaction), the'netresult is zero recoil in either direction.

One object of my invention is to simplify the design, construction, and operation of recoil-free guns.

Another object is to provide a recoilless rie using an imperforate cartridge case.

Afurther object is to provide a recoilless rifle wherein more eicient burning of the ammunition rounds propellent powder is accomplished.

A still further object is to provide a recoilless rifle in which the amount and temperature of the rearwardfow of 'gases used to neutralize recoil-l are reduced.

, Fig; 1' gun. showing further4 details of my invention; and

An additional object is to provide a recoilless rifle in which the projectile, after being red, acts as a valve influencing the action of the propellent powders gases on the venturi.

Theforegoing and other objects and advantages of Fig. 3'is'a cross section taken along Vline Y3 3 offFig, 1 showingother4 details of the presentinvention.

, the barrels wall.

. 41 l 17"tliat^terminates at'a flange 18l which is also locatedton the barrel. This ange, it will be shown later, serves asa seat for recoil neutralizing sleeve 11 when that sleeve is joined to thefbarrel.

Formed in the wall of the barrels rearmost portion, between its confluence with chamber 13 and ange 18, are a plurality of openings 19 (see Figs. 1 to 3). These openings, which may be of any convenient size and shape, depending upon various parameters, ,prefrablyfare spaced at equal angular intervals relative to the barrels axis and are dimensionedto .present a. certaintotalarea` of opening.

Fig. 3 shows openings 19'as extending radiallythrough This has been done because, in the illustrated embodiment, only a rearwardly actingirecoil force is of such magnitude as to require counteraction. As earlier mentioned, my invention also contemplates the neutralization of a rotationally acting recoilforceg: ifit should be'of such magnitude as to warrant counteraction, as is Vthe case with rifled guns. In the lattercase, openings 19, instead of b eingformed on imaginary radial lines, as.v indicated inFig. 3, would be formed on imaginary chordal. lines (not shownywhose direction would beV opposedjto thatv ofthe riings in the gun barrel, so as to enable the gases flowingtherethrough to induce a torsional force on barrel 10 to neutralize rotational recoil.

Internally, chamber 13 is provided with the convenient-` ly shaped and dimensioned ammunition recess 21.wh'icl1 matingly accommodates cartridge case of ammunition roundi12. Issuing from Vthe forward end of the ammuni.y tion recess and extending through the barrelsforward portion 14 to the muzzle (not shown) is the bore 22 (seeA Fig. 2). This bore is represented ashaving riing com-v prising the lands 24- and the grooves 25. However whether or not the bore is rifled is of no critical im, portance to my invention. The ried boreis shown only because the projectile 26 forming part of ammunition.

. round`12 is provided with a rotating band 27 Whichopf- The basicY structural components of the illustrative I embodiment of` my invention are the barrel 10, the

chamber 13, the recoil neutralizing sleeve 11, andV the'r ammunition roundA 12. The essential details of these components will now be described.

Barrel and chamber from ignition of the ammunition rounds propellent. Actually, however, it is possible to make the chamberl and barrel in two separate Vparts, skillfully designingV their juncture so as to accomplish the same ready gas flow.

Infthe illustrated embodiment, chamber 13, for practical reasons, is .represented as having atapering diameter which increases from its forward end 15 to` its; rear end 16.. However, it isnot to be construed that this condition,

althoughpreferable, is mandatory. Actually, chamber 13r co uld,.y if desired, be of cylindrical or-other'geometric shape.

The, rearmost portion. of barrel 10 is.provided,' nea l its confluence with chamber 13, with an external thread tionally may be pre-engraved, as shown, or plain (not shown).

rotating band, bore 22 normally would bey smooth.

Formed in the rear end of ammunition recess 21, and;

concentric therewith, is a somewhat larger diametered re= 'Y cessvhaving a thread,30 whose root diameter (i. e., the diameter near Vtheammunition recesss axis) is somewhat'l larger than Vthe ammunition 'rounds recess. As will later be shown, this thread forms a convenient means for secur.- e ingcartridgecase 45 of the ammunition round incharnber. 13. In order. to facilitate and to hasten thisprocessras:v well as. the removal of a cartridge case remainingi'infthef barrel afterring, thread 30 maybe interrupted byja plu? rality ofaxially extending paths, preferablyV equally spacedY and of equal angular expanse relative tothe lbarrels axis.

Recoil neutralizing sleeve Recoil neutralizingv sleeve 11, as shown inFigs. 1 ax1d2,. comprises a rear portion 33' and a forward, neckpor.- tion'34. Y

Rear portion 33 is provided with a conical openingmb whosef smaller diametered end36 is toward the barrels openings 19,- and whose largerdiametered end'37"is to, wardthechambers rear end 16. Y

Forward VneckY portion 34V is provided- With a recess- A38'which is-adjacent to, but somewhat lar-gerin diameter; than, .theconicalopenings' smaller end`36.-` Asbest shown' Should theprojectile not be equipped with a in Figs. 1 and 2, recess 33 has a particular shape relative to conical opening 35.' As with the blending between chamber 13 and barrel 1G, the shape of recess 38 is for the purpose of permitting optimum operation of gases produced yby ignition of the ammunitions propellent. Adjacent this recess, and also in the recoil neutralizing sleeves forward portion 34, is the threaded opening 39 by means of which the recoil neutralizing sleeve is later assembled to gun barrel 1G.

On the exterior of the recoil neutralizing sleeve is the electrical terminal block 4f) having the quick connect-disconnect contact 41 (see Fig. 1). This contact is connected by the electricity-conducting wire 42 to one side of a convenient source of electricity (not shown). The other side of the source of electricity is connected to barrel by means of the electricity-conducting wire 43 (see Fig. 1).

The recoil neutralizing sleeve is assembled to barrel 10 by passing the barrels forward portion 14 through the sleeves forward, neck portion 34, and then engaging the sleeves thread 39 with the barrels thread 17 until the inside of the neck portion is sealingly seated against the barrels flange 18 (see Figs. l and 2). The barrel therefore, completely closes the forward end of the sleeves neck portion 34.

When properly assembled, the sleeves recess 38 lies spacedly opposed to the barrels openings 19; the smaller diametered, forward end 36 of the sleeves conical opening is toward the barrels flange 18, and that openings larger diametered, rear end 37 is toward the chambers rear end (see Fig. l). In addition, the interior surface of conical opening 35 and adjacent recess 38, in conjunction with the concentric external surface of barrel 10, define an uninterrupted annular venturi passage surrounding the chamber (see Figs. l to 3). As shown in those figures, smaller diametered end 36 of the sleeves conical opening 35 substantially opposes the confluence of barrel 10 and charnber 13 to form the venturis throat (i. e., the constricted portion); the sleeves recess 3S adjacent the conical openings smaller diametered end 36 and part of the barrel which contains openings 19 form the forward or input portion of the venturi (i. e., in front of the throat); and the sleeves conical opening 35 and the chamber form the output portion of the venturi (i. e., to the rear of the throat).

Ammunition round Ammunition round 12, for the most part, resembles well known ammunition rounds in that it comprises a cartridge case 45, a primer 46, earlier-mentioned projectile 26, and propellent powder 47.

Primer 46, preferably electrically detonatable through the agency of the electricity-conducting wire 48, connected to a heating or spark element (not shown) within the primer, is accommodated in usual fashion in the head end 49 of the cartridge case.

Earlier-mentioned projectile 26 is accommodated in any convenient manner in the neck end 50 of the cartridge case and, optionally, is provided with the aforementioned rotating band 27. As mentioned above, if the gun barrel is not rifled, no rotating band need -be provided on the projectile. The presence or absence of the rotating band and rifling, however, has no serious influence on my invention.

Propellent powder 47, as is well known, occupies the space inside cartridge case 45 between primer 46 and projectile 26.

However, the illustrative ammunition round has a feature which inventively associates it with my novel recoilless rifle and distinguishes it from prior art ammunition rounds. Near its head end 49, the cartridge case is provided with a projecting circular -band upon whose circumference the thread 51 is formed (see Figs. 1 and 2). This thread, as shown in those figures, is engageable with the ammunition recesss thread 30 in order to hold the ammunition round in the barrel.

In order to facilitate and to hasten insertion of the ammunition round into the barrel and removal therefrom, the spaces 52 (one of which is shown in Fig. l) extending in an axial direction, are formed in the band. These spaces preferably are equally spaced 4from each other, and have the same expanse angularly relative to the ammunition rounds axis. Naturally, these spaces correspond in shape and number, although they are slightly larger in size, to the ammunition recesss threaded lugs 31.

in effect, spaces 52 divide the cartridge cases band into a plurality of lugs 53, four in the present instance. These lugs, preferably are equally spaced `from each other, and have the same expanse angularly relative to the ammunition rounds axis. As with spaces 52, the lugs correspond in shape and number, although they are slightly smaller in size, to the spaces (not shown) formed in the ammunition recess. j

The manner of positioning ammunition round 12 into barrel 10, therefore, resolves itself in merely inserting the round, projectile 26 foremost, into ammunition recess 21 as far as the round will go, making certain to align the barrels lugs 31 with the ammunition rounds spaces 52, then rotating the round by its head end 49, which remain outside the chambers rear end 16. In so doing, the rounds lugs 53 threadedly engage the barrels lugs. When no further rotation of the ammunition round is possible, the round is seated in ammunition recess 21 so that the cartridge cases lateral wall is firmly supported by the charnbers rear portion 16, the barrels openings 19 lie just forward of the cartridge cases neck end 5f), and pre-engraved rotating band27 is in alignment with, but not enga-ged to, the barrels rifiing. After the ammunition round is in barrel 10, electricity-conducting lead wire 48 is connected to quick connect-disconnect lcontact 41.

in order to remove the cartridge case remaining in the barrel after firing the ammunition round, electric lead wire 42 having been disengaged from contact 41 by the blast of gas issuing from the venturis output portion, head end 49 which projects from the rear end of the barrel is rotated to unlock lugs 53 and 31, and the cartridge case is pulled axially from the barrel.

Although Fig. 2 depicts the ammunition rounds rotating band 27 as being pre-engraved, it must be understood that this condition is not mandatory. In other words, a plain, unengraved rotating band could be used just as well. As a matter of fact, rotating band 26 could be dispensed with altogether, if desired.

From the foregoing explanation, it is apparent that the cartridge cases head 49 acts as a breech block Widely used in firearms generally. Since, with my invention, the need for such breech block has been eliminated, the construction of the guns rear end is greatly simplified with a consequent reduction in weight.

Operation To operate my novel weapon, ammunition round 12 rst is inserted into the barrels ammunition recess 21 in the manner earlier described, and electricity-conducting wire 48 is attached to the terminal blocks contact 41.

After aiming in any convenient manner, the circuit to primer 46 is closed by operation of a trigger switch (not shown) and the primer is detonated. Detonation of primer 46 explodes propellent 47. The force resulting from ignition of the propellent builds up within the cartridge case to the point where projectile 26 begins to move through the guns barrel to the muzzle end. As the projectile moves out of the cartridge case, some of the gas resulting from ignition of propellent 47 passes between the cartridge case and the rear end of projectile 26 and instantaneously escapes through the barrels openings 19 into the venturis input portion. From there it passes the venturis throat, moves rearwardly through the venturis output portion, then out the rear end of the firearm.

Duringgthese actions the recoil neutralizing forces are createdi In essence, the rear end of projectile 26 acts as' a' valve and canbe shaped along its length toallow av desired opening betweenitself vand the neck of the cartridge case perlunit'distance of travel of projectile from the cartridge case- In'- addition, the combined area of the barrels openings can ybe made toany optimum amount. isconveniently possible'to regulate the amount of gases which How through the openings by Vappropriately designing the'size, shape and number of openings 19, as well as thefprojectile-cartridge case relationship.

From the foregoing, it will be apparent that I have simplified the design, construction, and operation of recoil-free'guns; that I have provided a recoilless'rifle using an imperforate cartridge case; that I have provided a recoillessrifle wherein more ecient burning of the ammunition: rounds propellent powder yis accomplished; that I have provided 'a recoilless'riflein*which the amount and temperature of the rearward ow of gases from'the rear endof the gun are reduced; and that I have provided' a recoilless rifle in which the projectile, especially during the initial movement from the cartridge case, acts as a valve influencingfthe action of the propellent powders gases on the venturi.

My invention is amenable to Various modifications and variations without departingfrom its originalspirit and scope.- For example, in order Yto have the outersurface of chamber 13 and the inner surface of recoil neutralizing sleeve `11 define an'annular venturi passage between'thernselves, my invention contemplates the combination of variously shaped barrels and recoil neutralizing sleeves;

Still other possible ways in which my inventionv can'be modi'ed and varied pertain to the ammunition round and to the ammunition round-barrel relationship. In order to have the rear end of projectile 26 actasv a valve to control the amount of gas flowing from the open'end of the cartridge case, the projectiles rear end can be vfluted or contoured in the region enclosed by the'cases neck end 50. Then, upon firing the ammunition round, the projectile need move only a predetermined amount before gas from the propellent begins to ow from the cartridge cases neck end along lthe fluted or contoured portion of the projectile and out through the barrels openings 19. If it is desired to have gas flow from the cartridge case even before the projectile'begins toV move therefrom, the cartridgel cases'neck end can'be closedY by some frangiblematerial used in conjunction with the proL jectiles rear end. With this type of arrangement, the frangible material would be fracturedY upon firing the round. Then, before the gas pressure inside the cartridge case would have an opportunity to build up sufficiently to Thus, it

. 3 begin moving thev projectile therefrom, any desired. amount ofgaswould bel allowed to passfrorn the car'- tridge-case; throughn the 'space previously occupied' by the frangible'material, into the venturi.'4

Still another modication contemplate is to make thev forward end of ammunition recess 21 somewhatlarger than the cartridge cases neck end 50; Then, upon firingv the ammunitionY round, the difference in size betweenA they are believed to be within the purview of the invention already disclosed. Because such variations and modifications are possible, Ido not wish to be limitedvin'patent coverage bythe limits of the foregoing description andV illustrative drawings, but rather only by the-rnetes and bounds of the'following claim.

I claim: A recoilless vfirearm including a gun tube having a cylindrical forward portion blending into a taperedrear,V

portion and having a plurality of openings forward yof` said rear portion, saidV rear portion being arranged to receive the cartridge case of an ammunitionround with the forward edge of said case in a plane substantially" coextensive with the rear edges of said openings and said forward portion being arranged to receive the roundsA projectile withits rotating band located between the front andrear edges of said openings, and a recoil neutralizing sleeve encircling said tube to form between it and said tube a venturi having its rear end open to the atmospherel and joined at its front end to said cylindrical portion at a point forward of said opening.

References Cited in the iile of this patent UNITED STATES PATENTS 625,440 Elliot May 23, 1899 1,434,044, Cooke O.ct.f31, 1922 1,933,694 Allen Nov. 7,` 1933 2,436,364 McDowell Feb. 17, 1948 2,478,958 Wheeler et al Aug. 16, 1949 2,529,504 Kroeger et al. Nov..14, 1950 2,537,063 Kroeger et al. Ian. 9, 1951 2,693,757 Brandt Nov. 9, 1954 2,701,984 Terce Feb. 15, 1955 Y FOREIGN PATENTS 139,773 Germany Apr. 3, 1903` 233,347 Great Britain Mar; 11, `192.6

494,910 Belgium Aug, l, 1950 673,431 Great Britain June 4, 1952 These modifications and'

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