US2112831A - Compensator for ordnance - Google Patents

Description

April 5, 1938. R. M. cUT'rs, JR 2,112,831

GOMPENSATOR FOR ORDNANCE Filed Dec. 7, 1955 2 Sheelzs-Sheecl l FIG. El.

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RM. E u TTBM April 5, 1938. R. MQ cUT'rs. JR 2,112,831

CoMPENsAToRVFoR ORDNANCE Filed Dec. '7, 1955 2 Sheets-Sheet 2 RMEUTTSJ dwg Patented Apr. 5, 1938 uNlTED STATES PATENT OFFICE 15 Claims.

This invention relates to compensators for ordnance and has for its object to provide a construction more eilicient in use and less costly to manufacture than those heretofore proposed.

With these and other objects in view the invention consists .in the novel details of construction and combinations of parts as will be more fully hereinafter disclosed and particularly pointed out in the claims.

Referring to the accompanying drawings forming a part of this specification in which like numerals designate like parts in al1 the views,-

Fig. 1 is a diagram illustrating in substantial vertical cross section the construction of a compensator employing the principles of this invention;

Fig. 2 is a view similar to Fig. 1 but in which there is provided a series of compensator chambers disposed within an enclosing supplemental compensating chamber;

Fig. 3 is a view similar to Figs. 1 and 2 but illustrating a modification of the construction shown in Fig. 2;

Fig. 4 is a substantial vertical cross sectional view illustrating a modication of the construction shown in Figs. 2, 3, 8, 9 and 10;

Figs. 5, 6 and 7 are substantial vertical cross sectional views illustrating modifications of the constructions shown in Figs. 3, 8, 9 and 10;

Figs. 8, 9 and 10 are substantial vertical cross sectional views illustrating modifications of the construction shown in Fig. 3; and

Figs. 11 and 12 are respectively vertical sections taken longitudinally and transversely of a further compensator modification wherein all of the compensator chambers are substantially coaxial Within their lengths, Fig. 12 being a view taken as on the broken line I2-I2 of Fig. 11 and looking in the direction of the arrows.

According to Fig. 1 there is provided an outer chamber I threaded or otherwise secured to an integral portion 2 of the gun which may be the muzzle end of the jacket of a machine gun. The forward end of this chamber is shown tapered as at 3 to provide an orifice l of a diameter suicient to permit the projectile from the gun barrel 5 to pass therethrough. Within this outer chamber is a second chamber 6 secured at one end to the gun barrel, which may or may not be reciprocatory, and having its other end forwardly tapered as shown at 1 providing an orifice 8 also adapted to permit passage therethrough of the projectile from the barrel. The chambers I and 6 may conveniently be made similar to those disclosed in prior known constructions and generally consist of a metallic wall in which are formed a plurality of narrow slots or apertures for egress of the gases of explosion accompanying the projectile.

These slots are substantially parallel to each other and formed as indicated at 9 in the portion of the wall of chamber I above the horizontal axial plane thereof, said slots extending in spaced relation rearwardly of thev chamber to a point slightly back of the middle thereof. There may also be provided a plurality oi similar slots I0 in the forward tapered portion 3 of this chamber. Slots II and I2 are formed in the inner chamber wall 6 similar to the slots 9 and I0, except that the slots II and I2 are preferably disposed on the sides of said chamber leav- 15 ing the extreme top and bottom wall portions of said chamber imperforate. Also, the slots II and I2 are preferably disposed in transverse planes of the inner compensator chamber, intermediate similar planes passing through the slots 9 of the outer compensator chamber, so that 20 the gases leaving the combined compensator structure will not have a straight path to the outside atmosphere, but in passing from the slots II and I2 said gases will impinge upon imperforate wall portions of the outer compensator chamber and then have to travel longitudinally of the device to reach and pass through the slots 9. In forming the slots 9, I Il, II and I2, the cutting tool may be actuated in a plane forming with the axis of the compensator chambers, or it may be actuated in a plane making a different angle to said axis, according to whether the particular gun to be tted with the compensator would have its action improved 35 by a rectilinear or oblique emission of gases through the slots. It will be understood, of course, that the two compensator chambers I and 6 will be coaxially mounted and that the diameters thereof will be sufficient to create a material space between the walls of said chambers.

In the form of the invention illustrated in Fig. 2, there is provided the same integral gun portion 2 and barrel 5 as described above, but the outer compensator is made of an increased length over that shown in Fig. 1 to accommodate a plurality of serially connected inner compensator chambers. That is to say, the outer compensator I5 has its rear end rigidly attached to the sleeve or other gun mounting 2 and has its forward end provided with substantially the same forward tapered portion 3 as above described except that the orifice 4 heretofore described is in Fig. 2 shown internally threaded to receive the forward end of an imperforate tube I6 whose rear end is adapted to have a somewhat tight but sliding fit upon a forwardly extending tubular neck I1 of an intermediate inner compensator I8 whose opposite or rear wall threadingly receives the forward end of the tapered portion 1 of the rear inner compensator I9. The rearmost end of this compensator I9 is adapted to have a somewhat tight but sliding iit over the extreme end of the muzzle of the barrel 5, and when the parts are assembled as shown in Fig. 2 it will be seen that the outer compensator I5 is of a length sufficient to cover the serially connected parts I6, I8 and I9 with the rear end of the member I9 jammed against the end of the gun mounting 2, it being understood that the inner compensators I8 and I9 as well as the tube I6 are uniaxial with respect to each other and coaxial with respect to the outer compensator I5. The two inner compensators I8 and I9 are provided with respective slots 20 and 2| similar to each other and likewise similar as to placement to the slots II shown in Fig. 1, and the tapered portion 1 of the rear inner compensator I9 is likewise provided with slots 22 similar to the slots I2 of said Fig. 1.

The outer compensator I5 may be said to have slots similar to the slots 9 and I0 of Fig. 1 in that they are similarly formed and spaced, but they do not extend rearwardly beyond the intermediate inner compensator I8, thereby leaving a material portion of the wall of the outer compensator imperforate all around against which the gases emerging from the rear inner compensator may impinge. 'I'he slots 20 of the intermediate compensator may be in registry or not with the slots 9 of the outer compensator, it being shown in the drawings that the middle slot 20 is in registry whereas the other two slots have staggered relation with the slots 9 of the outer compensator.

'Ihe inner diameters of the rear and intermediate inner compensators are made substantially equal whereby it will readily be seen that the cylindrical portion of the rear inner compensator constitutes an expansion chamber for the gases of explosion as they emerge from the muzzle of the barrel 5 since said compensator nts over the exterior surface of the barrel and hence must have an inner diameter greater than the bore of the barrel. It will also be readily apparent that these expanded gases will be compressed in passing over the slopes of the tapered portion 1 of the said compensator and when the gases enter the intermediate inner compensator I8 they will be permitted another expansion to fill the interior space thereof, but upon leaving the compensator I8 the gases will be restricted in passing through the reduced or neck portion I1 at the forward end thereof which neck has an internal diameter substantially equal to the internal diameter of the passage between the compensators I8 and I9, and that upon emerging from the neck I1 the gases will be permitted slight expansion inthe forward tube I6.

In Fig. 3 there is also disclosed a plurality of serially connected compensator chambers, with an outer compensator enclosing a portion of one and all of another of the serially connected compensators. In other words, similar reference numerals have been given to parts similar to those hereinbefore described, but the intermediate inner compensator 25 differs from the intermediate inner compensator I 8 shown in Fig. 2 in that its cylindrical portion is extended rearwardly, ending as at 2B in close proximity to the foremost position of the reciprocable barrel 5 of a machine gun, for example, and when the structure of Fig. 3 is used in connection with guns without a reciprocable barrel, the space between the muzzle of the barrel and the end 2B of the compensator 25 will be relatively small so that the majority of the gases of explosion may enter the compensator 25 under substantially full velocity. The shoulders formed at the forward end of this compensator will, however, impede the forward drive of these gases and build up a pressure in the compensator suflicient to augment somewhat the lateral dispersion from the axis of the device through the space just referred to and cause such dispersed gas to enter the rearmost compensator generally identified by the numeral 21. This rearmost compensator 21 is threaded to the gun mount 2 and has a cylindrical portion extending forwardly to approximately the foremost throw or movement of the gun barrel if the latter is reciprocable, and it then tapers inwardly and forwardly as shown at 28 with its foremost end screw threaded externally on the intermediate compensator 25.

A plurality of apertures 29 are provided on the tapered portion of the rearmost compensator to permit the gases therefrom to enter the space between the intermediate compensator 25 and the foremost outer compensator 30 which latter has its rear end threaded externally on the rearmost compensator 21 and is similar in other respects to the compensator I5 shown in Fig. 2. Here again the slots 20 of compensator 25 may or may not be in registry with one or more of the slots 9 of the outer forward compensator 30, and it will be clearly observed that the compensator 30 encloses all of the intermediate compensator 25 and the tube I6, as well as the tapered apertured portion 28 of the rearmost compensator 21, with all compensators arranged coaxial with respect to themselves and the axis of the gun barrel.

In Fig. 4 is shown a modification of the construction shown in Figs. 2 and 3 and according to this modication the outermost forward compensator instead of being forwardly and inwardly tapered, is of the same cylindrical formation as indicated at 35 as the main body portion. To provide a restricted forward end of this compensator chamber, the tube I6 is, in this modification, provided with a divergent forward taper indicated at 36 with its outermost end screw threaded to the outer end of the compensator wall 35, the tapered portion 36 being provided with a plurality of apertures 31 to permit passage of gases therethrough as well as relief of pressure from the chamber of the outermost compensator. 'I'hus it will be seen that this construction is substantially a reversal of that shown at the end of the device illustrated in Fig. 2.

The construction according to Fig. 5 is a modification of that shown in Fig. 3, for example, wherein the intermediate compensator 25 and the tube I6 of the latter have been combined in an elongated cylindrical inner compensator 38. Also the slots 9 of the hereinbefore mentioned outer compensator have been omitted from the similar counterpart 39 constituting the outermost compensator of this modification, and the forward taper of this compensator is herein provided with a plurality of apertures 40 for egress of the gases in place of the slots I0 of the form hereinbefore described. On the other hand, the imperforate tube I6 is in this modification supplanted by an extension of the intermediate compensator, with slots 4I provided in its side portions. Substantially the only other principal difference resides in the provisionl of tapered shoulders 42 at the forward end oi' this modified intermediate compensator 88, ending in an oriilce 48 oi' reduced diameter and somewhat similar to the portion I1 of the corresponding compensator 25 shown in Fig. 3. The shoulder 42 has somewhat the same effect upon the forwardly moving gases as the shoulders shown in Fig. 3 on the compensator chamber 25. In conclusion it might be observed that the rear end of the forward outer compensator 39 is not threaded to the rear compensator 21 but when the Darts are screwed together this joint will be substantially gas tight, and the slots 20 are disposed in the intermediate compensator 88 to permit gases to pass therethrough into the conilnes of the compensator 21.

'I'he modication according to Fig. 6 shows a construction similar to both Figs. 3 and 5 and similar reference numerals represent similar parts. 'Ihat is to say, the diierences are that the walls of the compensator.39 of Fig. 5 are apertured in accordance with the showing in Fig. 3, and the slots 4| of the compensator 88 shown in Fig. 5 have been omitted.

According to Fig. 7 the construction of the compensators 27 and 30 shown in Fig. 3 have been duplicated but the tube i8 has been omitted and supplanted by an elongation of the intermediate inner compensator shown in said ngure. In other words, this said intermediate compensator 45 in this modication has been extended to the forward end of the outer compensator 30, is substantially cylindrical throughout its length and provided with a forwardly inclined or tapered shoulder 46 substantially identical with the similar shoulder 62 shown in Fig. 6 except that the shoulder t6 is spaced inwardly from the muzzle of the outer compensator quite an appreciable distance so that there is formed an irnperforate forward wall portion of the compensator 45 disposed opposite nearly all of the slots 9 and i0 of the outer compensator tu. The slots 20 of this innermost compensator are disposed substantially the same as the corresponding slots of the compensator 25 shown in Fig. 3, and the remainder of the construction is identical with said Fig. 3 except that the threaded joint shown in said gure between the compensators 2'! and 35 is replaced by the tight slip joint shown in Figs. 5 and 6. y

The construction shown in Fig. 8 diers from that shown in Fig. 3 in that the slots 28 of the latter are replaced by slots 41 disposed in the upper portion of the wail of the intermediate inner compensator 25, and the slots 9 and i8 oi' said Fig. 3 are replaced respectively by the slots 48 and 49 disposed in the sides o1' the outer compensator 30. Additionally it is to be particularly observed that according to this modiilcation there is always an imperforate wall section of one compensator opposed to any slot or other opening in another of the associated compensators.

According to Fig. 9 there is a slight departure from the construction shown in Fig. 8 and residing in the fact that the innermost compensator 25 is herein provided in both its top and bottom wall ysurfaces with slots 50 of the type shown at 41 in Fig. 8, and the rear outer compensator 21 is joined to the innermost compensator 25 by a tapered or conical wall 5I having a slope which is the reverse of the corresponding part 28 in Fig. 8, but otherwise provided with the similar apertures 29.

The modiiication according to Fig. 10 shows an inner intermediate compensator 25, substantially a duplicate of that shown in Fig. 3, as well as outer end compensator 30, also substantially identical with its counterpart shown in said iigure. However, the outer rear compensator 21 is formed similar to its corresponding compensator shown in Fig. 9 with the exception that the rearwardly and inwardly tapered wall 5I of the latter figure is replaced in this gure by an imperforate wall 52 whose innermost end is spaced slightly from intermediate compensator 25 as indicated at 53, thereby leaving a circumferential passage between 25 and 52.

Whereas in Figs. 2 to 10 inclusive there has been illustrated a'serially connected compensator structure, in Fig. 11 there is shown a combination of coaxial compensators based upon the principles ot theA construction shown in Fig. 1. with Fig. 12 representing a vertical sectional view taken at right angles to the axis of the device shown in Fig. 11. For convenience in illustration the compound compensators of this modification are shown attached directly to the muzzle end of the barrel 5 but it will be understood that they could as Well be attached to other portions of the barrel mount. According to this modification the innermost compensator 55 comprises a substantially cylindrical chamber threaded at the rear end to the barrel and having its forward end extended at a reduced diameter to provide a tube portion indicated at 5S and threaded externally at its outermost end to receive thereon a nut 5l or other suitable element for securing sealing material indicated at 58 for closing the 'joint between the innermost compensator and the outermost. The opposite side walls of the rear cylindrical portion of this innermost compensator are provided with spaced slots indicated at 59. Prefeiably threaded to the rear end of the innermost compensator is the rear end of the intermediate compensator d of substantial cylindrical formation whose forward end terminates in an inwardly directed shouldered closure Si adapted to slidingly nt the exterior surface of the tube portion 56 of the compensator 55, with the top and bottom wall portions of this intermediate compensator provided with a plurality of spaced slots 62 preferably disposed in staggered relation with the slots 55 of the compensator 55. The slots 82 may be in number suilicient to extend forwardly of the foremost slot 59 as clearly indicated and therefore it may be said that substantially the entire length of the intermediate compensator is thus provided with slots.

In a similar manner the outermost compensator 63 is threaded at its rear end to the rear end of the intermediate compensator, the former exltending forward to entirely enclose said intermediate compensator, with the extreme forward end 84 of rthe outermost compensator somewhat similarly formed to provide a shoulder and sliding fit upon the outer surface of the tubular portion 58 of the innermost compensator, the sealing material 58 being disposed between the end of the outermost compensator and the nut 51. Thus it will be seen that the three compensators 55, S0 and 63 are coaxial and have their substantially cylindrical walls disposed in concentric but spaced relation from each other, the side walls of the outermost compensator being provided with a plurality of slots 55 staggered with respect to vthe positioning of the slots 52 of the intermediate compensator, and each compensator provided at its forward end with a shouldered portion against which the force of the gases may impinge or be the outer surface of the t directed in an effort to counteract recoil, whereby the gases in emerging from the barrel will be caused to move first through the slots 59 of the innermost compensator, thence through the slots 62 of the intermediate compensator 60 and nally through the slots 65 of the outermost compensator to gain the atmosphere, this path being Atortuous and occasioned by the pressure and velocity of the gas and its temporarvconiinement by the sealing of the bullet in the tubular portion of the innermost compensator.

In order that this invention may be better understood, attention is directed to U. S. Letters Patent No. 1,605,393, No. 1,636,357 and No. 1,773,260 granted respectively on November 2, 1926, July 19, 1927 and August 19, 1930 to Richard M. Cutts and Richard M. Cutts, Jr. and disclosing compensator devices adapted for attachment to the muzzle of guns of various calibers and powers for the purpose of overcoming climb and reducing recoil. However, in service and in actual operation of these devices certain minor factors appeared which were to a certain extent undesirable, and there were certain undesirable effects developed by the operation of these structures, and which were inherent to the use of these devices, and therefore this present applicationvcovers devicesv which will have increased efficiency over the structures of said patented devices and which additionally overcome the undesirable factors referred to above, this application covering a combination in fltting of devices, and application of the forces developed, to various parts of the gun h structure.

In other words, it was disclosed in said patents how the gases of explosion, as they emerged from the barrel muzzle, were permitted first to expand due to the increased internal diameter of the expansion chamber portion of the compensator, and then the pressure of said gases was increased when the forwardly moving gas column impinged upon the inner surface of the tapered portion of the compensator termed the compression chamber, the latter action resulting in the creation of a friction having the characteristic of a blow imparting a forward drive to the entire firearm overcoming an appreciable amount of the normal recoil. Further, it was disclosed how the apertures in the wall of the compensator were designed to permit the escape of most of the gas under its increased pressure, and that the imperforate wall opposite said apertures received the force of the expanding gases resulting in a transverse movement of the compensator in a direction opposite to the gas escape through said apertures. 'I'hese same functions and principles are likewise existent in the present invention and therefore the precise description and development of these actions will not be given in detail since the similarity of chamber construction to that disclosed in said patents is readily apparent.

It is desired to point out that the term "compensator" has now been accepted by the military branches of the U. S. Government, as well as by the purchasing public asV defining a device for attachment to a gun muzzle which is provided with one or more chambers adapted to receive the gases of explosion and to act upon said gases in manners to overcome the climb tendency as well as to reduce the recoil of the weapon. 'Iherefore, in the claims this word compensator will be understood to have this meaning.

Various arrangements and forms of slots are disclosed in the above mentioned patents, and therefore it is not desired to be limited to the types and arrangements of slots disclosed in the accompanying drawings. A change in this form and arrangement would be evident to anyone skilled in the art.

It will be understood that every gun has its own individual characteristics, every type and caliber of shoulder gun, automatic and semi-automatic rifles, machine guns, submachine guns, Shotguns, and major ordnance, requiring the flexible application of power of the devices covered in said patents, the present application covering the devices necessary to overcome undesirable factors developed in the application of compensators to any of these mentioned or other guns, under various load conditions, in addition to other matters set forth hereinafter.

In many machine guns, the recoil of a reciprocating barrel is used to operate the mechanism of the gun. In high power guns the recoil power of the reciprocating barrel is far greater than is necessary for operating the mechanism,v thereby creating strains and impact blows in the operating mechanism which are highly detrimental to its longevity, and positiveness of continued operation. As seen clearly in Fig. l an inner compensator 6 may be fitted to the reciprocatory barrel 5, this compensator to be of such graduated value in reduction of recoilas to permit enough recoil of the reciprocating barrel to insure operation of the gun mechanism, while negativing the remainder. Under these conditions the design of the inner compensator cannot be of such value as to apply its full powers of recoil reduction to the reciprocating barrel, for if it were then the gun would not operate successfully. By attaching an outer compensator l to the gun jacket or muzzle gland 2, that part of the possible recoil value in the inner compensator 6 winch must be sacrificed to insure the operation of the gun mechanism, is recovered and applied to the general recoil reduction of the entire gun, at the same time realizing and utilizing the increased values of the combined inner and other compensator construction.

This invention includes the principles disclosed in said patents, but adds to the novelty thereof in that the devices made in accordance with this invention will, more specifically (1) increase the recoil reduction over the devices of said patents; (2) reduce the undesirable concussion, or report, produced by the action of the said patented devices, under certain circumstances; (3) hide the normal muzzle flash of guns, even when the latter have unbalanced loads, as well as conceal the muzzle fiash which under certain circumstances is augmented by devices, designed according to said patents, when certain gunpowder and load conditions are present; and (4) permita new application of the power, developed by the devices, to separate parts of the gun structure.

In general the power of the muzzle blast of a gun lies in the velocity of the gas, and the pressure of that gas; the pressure of the gas is of but little use normally owing to the existing velocity, and the greater the velocity the less the availability of the pressure for use in any circumferential or radial direction. In the patented devices the two distinct power elements existing in the muzzle blast are reacted into one usable force. The velocity is checked and expended in a counterrecoil action; the reaction of the checking of the head of the column of gas resulting in a very great increase of usable pressure and the production of great heat at the point of impact of the gas column. Lateral expansion of a circumferential or radial nature is nullilled by the walls of the expansion and compression chambers of the device. The result is a building up of very high usable pressure in the expansion and compression chambers, and by porting the expansion and compression chambers as described in the aforementioned patents, this pressure may be used in direct or compound reactions to overcome or produce movements of the muzzle and an additional recoil reduction other than that caused by the arrestation of the forward velocity of the gas column.

It will be understood that the porting must always be of sufficient area and capacity to discharge the built-up, gas pressure in the desired directions before this pressure can materially raise the muzzle pressure of the gun and travel back into the bore. The pressures generated are quite high, owing to theifact that the impact of the gas is as the square of its velocity; gas being compressible, the rebound from this arrestation is directly against the velocity of the rest of the oncoming blast. Ballistically speaking the time element of the application of this power is considerable and affords ample time for its absorption and use. Actually, this is the same power development which causes a slight obstruction in a barrel to swell or burst the strongest gun, although the obstruction at no time causes but a slight arrestation of the forward velocity of the gas. The strength of the expansion and compression chambers must be sufficient, in coordination with the porting area, to resist rupture, and therefore the porting area is calculated to prevent an undue rise in pressure.

As may be deduced from the above, and is conrmed by many spark photographs, the greatest pressure in the patented devices exists at the forward end of the device, the pressure decreasing rapidly toward the rear of the device as it approaches the gun muzzle. With powder producing some smoke, gas at a very high velocity can be seen in said photographs as issuing from the ports, as would be expected, resulting from. the building up of pressure by the reactions. Such photographs show a high velocity of this gas as measured in distance travelled in comparison with the known velocity of the projectile which appears on the same negative, and in said photographs with guns of high power, the emission of the gas particularly from the front end ports of the patented devices, carries a heavy compression wave in the opposing air which, when the gas velocity is reduced by air resistance to the speed of sound, becomes a sound wave; this sound wave is proportional in intensity to the blow delivered by the speed of the gas discharge, such discharge by the 'ports being in a more or less lateral or radial direction to the axis of the gun bore, wherefore this sound wave reaches the gun rer in high intensity, and is highly disagreeable except in guns of low power.

(l) Increase in recoil reduction-It has been found that the gas, issuing from the ports of the patented devices, has more power and velocity than is necessary in medium and high power guns to overcome climb, and it has been found necessary to so direct and position these ports that their full value is not used, for otherwise an unwanted down drive of the muzzle will occur; this excess power can not, with the patented designs in question, be used in further reduction of recoil; the excess power therefore passes out into the air and is wasted. y

In the devices covered by this\application, a gas blast of suiiicient veocity and power is emitted in the desired direc ion to overcome the climb of the gun,y and the extra power is retained in the device and used in further reduction of recoil. Particularly in Figs. 2 to ll inclusive it will be seen how this is accomplished, for the gas leaving the barrel isdirected into the rst inner compensator chamber in prolongation of the barrel, and from this chamber it passes into the intermediate or next compensator such as those indicated by the numerals I8, 25, 38 and 45. However, it will be observed that these intermediate chambers just mentioned have their forwards ends formed with a reduction in diameter at the outlet thereof, which outlets are identied by the numerals l1, and 43, and also the tube 56 shown in Fig. 1l; therefore the forward directional drive of the gas blast impinges directly upon the shouldered portions associated with these outlets, resulting in what might be termed a forward blow, and this is in addition to the forward counterrecoil action resulting from the initial impact of the gas column on the tapered slopes of the first compensator chamber into which the gas passes, such slopes being indicated by the numerals 1, 28, 5I and 52. With particular reference to Fig. 11, the initial impact of the moving gas column upon leaving the muzzle is directed upon the shouldered and reduced end portion of the innermost chamber 55,

but because the tubular portion 56 has comparative length, the bullet passing therethrough will establish a seal for a longer time than was possible in the case of the patented constructions referred to, and therefore the effect of the forward drive, initiated by the impact of the gas column, is prolonged. It will be understood that whereas the various apertures are herein shown as substantially formed at right angles to the axis of the barrel, they may be formed obliquely thereto as shown in the patents referred to, in order to augment the counterrecoil action.

(2) Reduction of report-Owing to the building up of high pressure in the patented devices the gas is discharged directly into the air at quite high velocities, the gas carrying a heavy compression and sound wave which is objectionable as stated. On the other hand, as will be seen from the drawings, in the devices covered by this application, the gas is not discharged directly into the air but is made to travel through one or more chambers, finally being ported from the outer compensator chamber at comparatively low velocities and pressure, the counterrecoil action absorbing some of the excess power, and the'expansion and cooling of the gas while passing through the serial chambers being responsible for further reduction in velocity and pressure. Sufficient power only is used with the lower pressure emissions to overcome the climb, the compression wave and sound wave therefore being much reduced in power, and this reduced wave is delivered in a generally radial direction from the axis of the gun bore, decreasing the intensity of the report delivered by the patented devices. All of the figures of drawings clearly show this effect of the escapement of the gas through the various compensator chambers before reaching the atmosphere, and therefore the above action can be fully appreciated.

(3) Hiding of normal muzzle flash-The amount of muzzle ash of guns is dependent upon the amount and type of powder used in relation to the volumetric capacity and cooling eifect of the barrel, as well as the length of the barrel. The muzzle flash oi' a gun with a normal well balanced powder load may be slight; if the barrel is shortened with the same powder load, the flash will be increased; and if the barrel is lengthened suiciently the flash will decrease to complete disappearance. The factors of quick and slow burning powders in the same gun have denite eects on muzzle ash, as well as the time taken by the bullet to traverse the barrel. With the normal gun barrel the flame of burning gases is immediately projected into the air, and immediate and rapid expansion and cooling takes place lowering the temperature below the combustion point in an exceedingly short time. The greater the volume of burning gases, the greater the muzzle ash in consequence. With one of the patented devices secured to the muzzle, the burning gases at the gun muzzle do not meet the same conditions for rapid expansion and reduction of pressure, owing to the interposition of the expansion and recompression chambers of the device and a definite increase in pressure and heat in the forward end of the devices as before explained, in consequence of which the muzzle ash of burning gases is not sufficiently and immediately cooled below the combustion point, and may extend into and issue from the ports of the patented devices. rendering the discharge of the gun quite visible at night, particularly with a load not well balanced. In the devices covered by the present application, such ame is emitted into the second chamber where expansion and cooling take place very rapidly, and the gas is below the combustion point when it emerges from the ports of the farthest chamber, with no flame showing at these ports.

A gun usually contains more powder than is capable of being burned in the bore during the time that the projectile is passing therethrough, particularly with the progressive burning powders now so generally in use. In consequence partially consumed and at times unburned grains of powder are ejected into the atmosphere at the gun muzzle, and since these powder particles have a high velocity, they are extinguished when driven through the atmosphere, and therefore they do not completely burn. 'I'his effect is clearly demonstratable and proved through the use of spark photography. The amount of this unburned powder in small arms is not great, but it is variable. On the other hand, it is a matter of common knowledge that after big gun practice on a battleship the decks contain considerable drifts, sometimes several inches deep,

of partially consumed powder grains that have been extinguished and blown back upon the deck.

In a gun tted with one of the patented de# vices referred to, these unburned powder particles traverse the expansion chamber but are checked in the recompression chamber in the same manner as the forward velocity of the gas is checked, and at this point the reaction of the checking of the velocity of the head of the gas column against the oncoming gas raises the pressure and creates heat, thereby restoring conditions which permit the powder to burn. Thus there is generated within such a device, heat, pressure and gas, the flame of which would appear and be discharged through the forward ports of such devices. In the devices covered by the present application, this discharge is into the space enclosed by the outer compensator chamber wall, where suiiicient expansion and cooling take place to obviate ame discharge from the ports in said outer wall.

In connection with this hiding of the flash, it is desired to point out that the present invention embodies a. design of construction permitting more oxygen to be present during the combustion of the gases within the device than with the patented devices. It is understood that powder generally speaking has the necessary oxygen within the powder mixture to support combustion, but this is not entirely true inasmuch as that, with present day machine guns when firing rapidly, an explosive mixture or powder dust is emitted from the muzzle of the gun and hangs in the air. This mixture is ignited occasionally by burning gases, causing what is known as a iash bomb. 'Ihis is particularly true with large caliber anti-aircraft machine guns.

By increasing the volumetric capacity of the compensators as shown in the accompanying drawings, there is more oxygen present in the compensator chambers during the final combustion of the gases at the true muzzle of the gun. This in conjunction with the valving down of the gases from one compensator chamber to 'the other, through multiple ports, gives reduced flash. Moreover the reworking of the gas through the multiple compensator chambers gives increased eiiciency.

(4) New application of poulet-The slots or ports according to this invention may be arranged either according to thoseshown in the above metioned patents or otherwise, as exigencies may demand. It will be understood that the arrangements of the ports determines the down drive effect which varies with every type of gun tted. In some cases it is quite possible owing to line of mount recoil resistance in relation to line of recoil action, that no down drive will be desired since the reduction in recoil will in itself be sufficient to reduce or eliminate any upward climb of the gun. In such cases the porting arrangement will be as shown in Figs. 5, 9 and 11 or some simple modication thereof. The modifying factor under these circumstances is that the ports are arranged diametrically opposite each other in equal numbers, so that the release of the gas is equalized. It is understood that if the release of gas is not equalized, a positive motion is given to the compensator and by means thereof to the gun in a direction away from the point of greatest gas release. From the above it will be understood that the actual arrangements of the ports will vary depending upon the particular gun to be fitted and the exigencias which have to be met, and in view thereof it is not desired to limit this invention to any exact disposition of the ports, since it has been found from practice that their location is a variable factor.

It is conceivable that the form of compensator shown in the above mentioned patents may be used in conjunction with a flash hider to cover the flash. 'I'he present form of hider consists merely of an imperforate tube secured around the muzzle of a gun and extending forwardly therefrom, the tube tending to cover the pencil of ame as it emerges from the muzzle. However, due to practical reasons, such a tube cannot be made sufficiently long to fulfill the purpose -for which it is intended, with the result that in present practice the flash extends for some distance beyond the end of the tube.

The ash hlder in and of itself has no function in regard to reducing the recoil of the gun. A combination of a iiash hider with one of the compensators shown in the patents referred to but fitted therein, would give the recoil reduction advantage oi one compensator plus a partial ash concealment. On the other hand, by the present invention additional recoil reduction is accomplished, and complete concealment of the iiash is eiected,-by the use of the multiple compensator chamber arrangements shown in the various modifications of the drawings when properly fitted to gun conditions.

The present invention relates to an increasein eiiiciency in compensators by the use of multiple chambers. The gas when released from the compensator chamber which first receives it, 'is still at high pressure, and it then enters successively the other compensator chambers, performing work therein, so that when it reaches the atmosphere, it is at a materially lower pressure than would have been the case were it released from the initial compensator chamber directly to the atmosphere. This action constitutes a valving down of the gas pressure, and it will be understood further that this same valving also eifeets a material diminution or elimination of flash.

Volumetric capacities are such that the combustion is more or less complete before the nal emission of the gas to the atmosphere since this capacity determines the amount of oxygen present. Moreover, the tortuous path which the gas must traverse slows its forward movement before it reaches the atmosphere, thus lengthening the time for complete combustion as Well as affording additional time for the absorption of the powers delivered. From actual tests by the U. S.' Army on patented compensators it has been found that the forward velocity of the gas at the muzzle of a gun has been reduced from 3500 down to 800 feet per second with the use of only one compensator chamber as disclosed in the aforementioned patents.

The present invention is directed to the use of one compensator chamber within another, either interconnected or not as desired, and in conjunction therewith there is a muzzle tube as shown in Figs. 2, 3, and 7 to 11; a modified tube is shown in Figs. 5 and 6. This tube in and of itself is an increase of efficiency since the gas is practically sealed within the compensator from the time that the nose of the bullet enters the rear end of the tube, to the time that the base of the bullet clears the front end of said tube. The length of time that the gas is worked determines the amount of energy that may be extracted, and therefore the use of the tube represents an additional gain in efhciency. This is a matter of record from tests conducted with the use of .45 caliber bullets as well as 9 mm. projectiles.

It is obvious that those skilled in the art may vary the details of construction as well as arrangements of parts without departing from the spirit of the invention, and therefore it is not desired to be limited to the foregoing except as may be required by the claims.

What is claimed isry 1. An attachment for the muzzle of Vfirearms having a movable barrel comprising a cylindrical casing adapted to'be attached to said barrel and constituting an expansion chamber for the gases of explosion 'as they leave the barrel, the Walls of said casing being conically formed at the forward end to provide a compression chamber for increasing the pressure of the forwardly moving gases, the walls of the expansion and compression chambers provided with apertures for releasing a portion of the gases under pressure, the remainder of the gases passing through a projectile opening disposed at the apex oi the compression chamber, said apertures tormed in diametrical portions of said walls whereby the gases in escaping therethrough tend to counteract recoil of the firearm; and a second casing iitted to a stationary part of the rearm and disposed in spaced relation about the first named casing, the walls of the second casing similarly forming a, cylindrical chamber and a forward conical chamber in prolongation thereof for receiving the gases Vfrom the rst named casing and similarly treating the same, the walls of the second casing provided with gas exits disposed to one side of a plane passing substantially through the axis of the second casing thereby leaving imperforate the wall portion on the other side of said plane whereby the gases in escaping through said exits will exert a pressure against the imperforate portion of the casing wall to produce a movement of the muzzle in the direction of said pressure.

2. A compensator for attachment tothe muzzle of firearms and comprising walls forming an expansion chamber having a projectile opening at its forward end, said opening establishing a gas seal with the projectile when the projectile is in said opening, said chamber being cylindrical throughout a substantial portion of its length and receiving the gases of explosion as they emerge from the muzzle; means to gradually increase the pressure of the expanded gases, said means comprising portions of the chamber walls conically tapered from the cylindrical portion to said opening to direct the forwardly moving expanded gases to and through said opening; a second walled chamber to receive the gases from said expansion chamber; and means to release the expanded gases under pressure to produce movement of the muzzle in a predetermined direction, said means including gas conducting passages between said chambers, and generally opposite imperforate wall portions thereof.

3. An attachment for the muzzle of firearms4 having a barrel movable with respect to the rest of the firearm, said attachment comprising a pair of substantially cylindrical chambers connected serially for gas communication, the rearmost chamber fitted at one end upon the movable barrel for slidable relation therewith, the other end of said chamber having its walls forwardly converged, the forward chamber fitted at one end upon the reduced end portion of the rearmost chamber and having its other end fitted with a projectile tube, the internal diameters of the main b ody portions of said pair of chamsaid third chamber secured at its rear end to a stationary portion of the firearm and having its walls forwardly converged at its front end and supporting said projectile tube, and gas ports in the walls of all of said chambers, the ports of g tion thereof opposite the ports of said rearmost chamber. Y 4. An attachment for the chambers, a rearmost chamber 4secured kto the firearm mount in substantially coaxial relation with the barrel of the weapon `and having the walls at its front end forwardly' .converged and supporting an intermediatechamber, the walls of said intermediate chamber extending both forwardly and rearwardly vof its pointw'of Vsupport whereby a portion of the intermediate chamber lies within the rearmost chamber, thexwallsr of the forward end of the inteririediatei'chamber` being inwardly directed" and terminating in a projectile passageY having a` projectile -K tube extending forwardly therefrom,l a third chamber secured to the 4rear/most chamber and having its walls in prolongation'bf the walls of the" main body portion of vsaid rearmost chamber, said third chamber encompassing a portion of said rearmost chamberv and substantiallyall of said intermediate chamber, the walls of the front end of said third chamber being forwardly'converged and supporting said projectile tube, gas ports in the converged walls of said rearmost chamber for conducting expanded gases of explosion directly into the third chamber, said ports opposed to an Vimperforate wall portion of said third chamber, and gas ports in the forward portions of said intermediate and third chambers.

5. AV compensating device for attachment to the muzzle of firearms and to receive the gases of explosion issuing therefrom, said device cornprising a pair of serially connected and coaxial chambers as well as a third chamber encompassing portions of the pair of chambers, all of said chambers being substantially cylindrical and having a projectile opening at an end thereof, said chambers also having gas conducting passages therebetween, the walls at the forward end of the encompassing chamber as well as the forward wall portion of one of the chambers of the pair of chambers having a conical interior surface extending from the cylindrical portion forwardly and inwardly to said opening to increase the pressure of the forwardly moving gases.

6. An attachment for the muzzle of'ilrearms comprising a pair of substantially coaxial charnbers one in advance of theother, one of said chambers receiving the gases of explosion from the barrel, a third chamber encompassing portions of the pair of chambers, all of said chambers having gas conducting passages therebetween, the gases of explosion passing unobstructedly from the gas-receiving chamber through its apertures into an imperforated portion of the encompassing chamber and .then passing unobstructedly through the apertures of the encompassing chamber directly into the atmosphere, the walls at the forward end of the encompassing chamber as well as the forward wall portion of the gas-receiving chamber having a forwardly and inwardly directed conical interior surface to receive the blow of the forwardly moving gases and thereby counteract the recoil of the rearm, the apertures of the encompassing chamber disposed in a substantial lengthwise portion of its wall as well as in substantially one-half of the circumferential wall portion thereof leaving the remaining wall portion opposite said apertures imperforate whereby the gases in escaping through these apertures v muzzle' of firearms comprising three substantially cylindrical coaxial willexert a pressure against the imperforate wall portion tending to produce a movement of the muzzle in the direction of said pressure.

7. An attachment for the muzzle of rearms having a barrel movable with respect to the rest of the firearm and comprising two substantially coaxial chambers, one of said chambers attached tov said barrel to move therewith and receiving the gases of explosion thereform, said chamber having gas outlets in its walls adapted to counteract recoil of the firearm when the gas passes therethrough, the other chamber attached to a stationary portion of the rearm and free of contact with the movable chamber and receiving vthe gases of explosion from the movable chamber, said other chamber having gas exits in its Walls as well as an appreciable imperforate wall portion opposite thereto adapted to produce a predetermined movement of the muzzle of the firearm when the gas passes through said exits.

8. An attachment for the muzzle of a flrearm provided with a barrel, comprising two substantially concentric chambers secured to portions of the firearm and adapted to have relative movement one to the other, the walls of said chambers free of `contact with each other, one of said chambers receiving the gases of explosion from the barrel, said chamber having gas outlets adapted to counteract recoil of the rearm when the gas passes therethrough, the other chamber receiving the gases of explosion from the flrst mentioned chamber, said other chamber having gas exits as well as an appreciable imperforate wall portion opposite thereto adapted to produce a predetermined movement of the muzzle of the firearm when the gas passes through said exits.

9. An attachment for the muzzle of firearms and for receiving the gases of explosion after leaving the muzzle, comprising two coaxial chambers one within the other, each chamber termiv nating in a projectile opening, the walls of said chambers provided with gas exits so disposed that the gases within the inner chamber after passing through its gas exits must traverse the space between the walls of the two chambers in order to pass through the exits of the outer chamber, said chambers mounted for relative movement one to the other upon firing of the weapon, the gas exits of one of said chambers so formed that the pressure of the gases passing therethrough will counteract recoil, the other chamber provided with a substantial imperforate wall portion opposite its gas exits whereby the gases in escaping through the latter will exert a pressure against said imperforate wall portion tending to move the muzzle in the direction of said pressure. I

10. A compensating device for attachment to the muzzle of firearms to receive the gases of explosion issuing therefrom, said device comprising a plurality of coaxial chambers, each chamber being generally cylindrical, the forward end of each chamber having its Walls inwardly directed toward the axis of the chamber and terminating in a projectile opening, the projectile openings of said chambers spaced from each other longitudinally of the device and connected by a projectile receiving tube, the walls of each chamber provided with slots for gas escape, each slot of a chamber disposed opposite an imperforate wall portion of another chamber, the slots of the outermost chamber disposed substantially above its horizontal axial plane.

11. A compensating device for attachment to the muzzle of rearms to receive the gases of explosion issuing therefrom, said device comprising a plurality of coaxial chambers, one chamber attached to a stationary portion of the firearm and another chamber attached to the barrel to have relative movement with respect to the first named chamber, each chamber. being generally cylindrical, the forward end of each chamber having its walls inwardly directed toward the axis of the chamber and terminating in a projectile opening, the projectile openings of said chambers spaced from each other longitudinally of the device, the walls of each chamber provided with slots for gas escape, each slot of a chamber disposed oppositev an imperforate wall portion of another chamber, the slots of the outermost chamber disposedsubstantially above its horizontal axial plane. l

12. A compensating device for attachment to the muzzle of firearms provided with a slidable barrel and adapted to receive the gases of explosion issuing therefrom, said device comprising a pluralityof coaxial chambers, one chamber at- 251 tached to a stationary portion of the firearm and another chamber attached at one end to said ilrst named chamber but slidably supported at its other end on the barrel, each chamber being generally cylindrical, the forward end of each chamber having its walls inwardly directed towardthe axis of the chamber and terminating in a projectile opening, the projectile openings of said chambers spaced from each other longitu.

dinally of the device, the walls of each chamber provided with slots for gas escape, each slot of a chamber disposed opposite an imperforate wall portion of another chamber, the slots of the outermost chamber disposed substantially above its horizontal axial plane.

13. A compensating device for attachment to the muzzle of firearms to receive the gases of explosion issuing therefrom, said device comprising a plurality of coaxial chambers, one chamber within another chamber, the inner chamber attached at its opposite ends to the outer chamber with an appreciable gas receiving area between the walls.ot bothchambers, each chamberbeing generally cylindrical, the forward end of each chamber having its walls inwardly directed toward the axis of the chamber and terminating in a projectile opening, the projectile openings of said chambers spaced from each other longitudinally of the device and connected by a projectile receiving tube constituting one of the attachments for the inner chamber, the walls of each chamber provided with slots for gas escape, each slot of a chamber disposedopposite an imperforate wall portion of another chamber, the slots of the outermost chamber disposed substantially above its horizontal axial plane.

14. A compensating device for attachment to the muzzle of rearms and to receive the gases of explosion as they emerge from the barrel, said device comprising a plurality of coaxial chambers, each chamber bounded by walls forming an enclosure within which the received gases may expand, the entire interior surface at the forward end of at least two of said chambers being forwardly and inwardly directed to receive and resist the impact of the gases moving forwardly therein whereby to increase the pressure of the expanded gases in each chamber, and

ports in the walls of each chamber for the passage of the gases therethrough, the ports of said chambers being disposed generally opposite imperforate wall portions of another chamber.

15. An attachment for the muzzle of rearms having a barrel movable with respect to the rest of the firearm, said attachment comprising a plurality of substantially coaxial walled chambers, the forward end of at least two of said chambers having their walls-terminating in an opening establishing a gas seal with the projectile when the projectile is in the opening, one of said chambers having its rearmost wall portion fitted directly upon said barrel, said 'chamber receiving the gases of vexplosion from said barrel, said chamber having gas outlets in its wall adapted to counteract recoil of the firearm when the gas passes therethrough, and an outer chamber having walls attached to a stationary portion of the firearm and receiving the gases of explosion from an inner chamber, said outer chamber having gas exits in its wall adapted to produce a predetermined movement of the muzzle of the iirearm when the gas passes through said exits.

RICHARD M. CU'I'IS, JR.

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