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Publication numberUS2453121 A
Publication typeGrant
Publication dateNov 9, 1948
Filing dateApr 20, 1945
Priority dateApr 20, 1945
Publication numberUS 2453121 A, US 2453121A, US-A-2453121, US2453121 A, US2453121A
InventorsCutts Richard M
Original AssigneeDorothea Lane Cutts
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Gas porting device for shotguns
US 2453121 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Nov. l9, 1948. R. M. CUTTS GAS, Pomme DEvIcEFoR soTGuNs i 5 Sheets-*Sheet 1 Filed April 2o, 1945' R. M. cuTTS GAS PORTING DEVICE FOR SHOTGUNS Nov. 9, 1948.

Filed April 20, 1945 s shets-sheez 2 I Cuffs Mentor Nov. 9, 1948. R. M. CUTTS 2,453,121

` @As Po'RTING DEVICE FOR sHoTeuNs Filed Ap'ril 2o, 1945 :s sheets-sheet 5 Patented Nov. 9, 1948 UNITED STATES Patent oFFlcE Richard M. Cutts, The Plains, Va., assignor of onehalf to Dorothea Lane Cutts, rllhe Plains, Va.

Application April 20, 1945, Serial No. 589,315

. 1 1 This invention relates to gas porting devices for ordnance, having for its object to produce a construction simple in parts, no more costly to manufacture, and more efficient-in use, than those heretofore proposed.

With `these and other Lobjects in view the invention resides in the novel details of construction and combinations of parts as will be disclosed` more fullyghereinafter and particularly pointed out in the claims.

Referring to the accompanying drawings forming a part ofgthis speciiication and in which like numerals designate like parts in all the views,

Figfl is a longitudinal sectional view of a device made in accordance with this invention;

Fig. 2 is a transverse sectional view of said devicefsaid view taken as on the line 2 2 of Fig. 1 and looking in the directionof the arrows;

Fig. 3 is a view similar to Fig. 2 but showing a modication of construction;

. Fig. 4 is a view similar to Fig. 1 but showing a further modication of construction;

AFig. `4a, is a fragmentary view in section of a modication of the gas porting arrangement shown in Fig. 4;

A Fig. 5 is a longitudinal sectional view of a modified form of the construction;

Figs. 6 and '7 are enlarged detail sectional views of modified forms `of ribs which may be employed in the device;

Fig. 8 -is a detail view in section of a modiiied form of choke tube; and

Figs.r9 to 13 inclusive are longitudinal sectional views of still further modifications of the invention.

This invention constitutes an improvement of the device disclosed in U. S. Letters Patent No. 1,773,260 dated August 19, 1930, granted to Richard M. Cutts and which` is directed to a compensating device for the muzzle end of a shotgun. The disclosure in that patent relative the vibrations given to the gun barrel, upon ringthe gun, and establishing what are known as bend and swing errors resulting in bullet impacts on the target whichareabove, below, or to one side of, the desired point of impact, such errors varying with the powder charge and other known conditions, is equally true and applicable to the instant invention. Also true and applicable are the statements in that patent relative the action of the leakage gas and its pressure in the interstices of the projected shot column resulting in the lateral expansion of the gas in said column and thereby imparting lateral velocities to the shot pellets in saidwcolumn (expanding said column), and the 4 claims. (ci. 89.44)

2 action of the powder wads upon the projected shot column to pan-cake the base of said co1- umn. repeat here the explanation of these actions which are 4set forth in detail in said patent, since the device of the present invention is so generally similar to that of said patent.

According to the present invention, there is provided a device equally, if not more, capable oi' reducing and/or correcting the undesirable features above referred to. aspect of the invention, approximately six inches or' the muzzle end of the gun barrel may be cut off and then the device is threaded on the short-l overall length and velocities as before without( destroying the balance of the gun. Hence, the shot charge reaches the expansion chamber without distortion of the shot pellets, and the extremely high temperature gases of explosion are permitted quick lateral exhaustion, with relation to the axis of the bore. through the ports of said chamber. The rear or powder` wads are practically consumed and/or torn to pieces by the time they leave the device due to the effect thereon of the hot gas turbulence in said chamber, and the leading or shot wad is given a rapid or increased forward acceleration due to the pressure of the gas in `theshot column while passing through the choke tube, which permits said shot wad after;

leaving the choke tube to move laterally of the axis of shot projection and hence prevents said wad from fdrifting back into and disrupting the projected shot column. In traversing the expan-g sioncharnber, the shot column elongates slightly and in this condition, and without the presence therein of the white hot leakage gas and friction heat, reaches and readily passes through the choke tube` without loss of velocity and` without the undue disturbance to the shot pellets which has heretofore resulted in pellet damage and/or deformation.

The single expansion ychamber of said patent, according to this invention, is provided with in ternal annular` ribs spaced from each other and disposed between the gas discharge openings whereby such expansion chamber is divided into a plurality ci' successive, independent, and unconnected chambers gradually and diminishingly 'exhaustingthe total of the gases of explosion while, at the same time, reducing appreciably the forward travel of such gases in the device, thereby increasing the reduction of recoil of the gun.

During the short period of time the shot column Therefore, it is believed unnecessary toV According to oneA is traversing the expansion chamber of this device, the Vibrations are being reduced and have substantially no effect upon the shot, but the damage due chiefly to the gas effect has been done. This improved device receives the column of shot, under the urge of expansion by the intei-nal gas pressure as well as the vibration, but the internal diameter of the ribs and/or the chamber proper may be made such as to materially prevent such expansion, and may cause recompression and reaiignment of any laterally dispersed shot pellets to any degree desired.

More specically, and referring vto Fig. l the shoegun barrel, which is indicated by the numeral 3, has threaded engagement Vas at i with one end of the cylindrical casing 5 defining the expansion chamber generally identified by the numeral 6, whereby said casing has rotatable adjustability, so that the exhaust ports, later to be described may be positioned top and bottom. The other'end of said casing may be in threaded engagement as at 'i with a removable choke tube 8 provided with any suitable means, such as an outwardly extending flange serving as a stop against' the end of the casing 5 as well as a means bywhich the tube member t may be screwed to said casing. The device comprising this invention has primarily to do with the expansion chamber to the end that various choking arrangements' andv forms may be employed or the gun may be fired without the removable end member, while maintaining the desired effects of gas control and shot column pattern resulting from the construction of this device.

The tube member 3 may be axially bored to 'i provide a conical surface lil extending from the extreme inner end A of said member to a point B, as well -as a second conical surface il joining saidv surface Ill and extending forwardly from the point B to a, point C, the slope of the surface Il being different from the slope of the surface I'; and said member may be provided with a third internal surface I2 which may be conical, cylindricahor of other generated formation, according to the desired shot pattern after the shot havefleft the device, said surface l2 extending from-the point C to the outer or forward end D ofsaid member. In Fig. l these slopes have been exaggerated so as to be readily visible or apparent. (Dnl'thel'oth'er'hand, the surfaces Wand il may be-made 'other than conical, e. g. they may be curved or arcuate and merge with each other and/or merge with the surface I2 as indicated in Fig. 4 tothe end that a continuous substantially smooth and unbroken inner surface may extend from the innermost end or point A of 'the tube member 8 to the outermost end point D thereof.

The conical surface i0, or its equivalent area ofthe continuous inner arcuate surface of the tubemember t, creates between the points A and B a compression chamber; the conical surface lil, or'its equivalent area of the continuous inner arcuate surface of said tube member 8, creates between the points B and C a recompression chamber for the laterally dispersed shot pellets; andthe' surface or area l2 creates between the points C and D a control (choke or otherwise) for the shot pellets with regard to the pattern desired when said pellets leave the gun. The internaldiameter at the muzzle of a choke tube determines the degree of choke obtained, wherefo'retiie choke tubes are provided with different muzzle diameters and are made interchangeable in orderv to obtain a shot pattern of any desired degree.l `In any choke tube, the sizeand shape of the sloped or curved area B-C will be suflicient to coactively engage the shot pellets without detrimental effects thereon, and to direct said pellets fairly smoothly into the choke represented by the area C-D, in accordance with the powder charge and size of shot used, all as brought out in detailed explanation in said patent.

The shot,l on emerging from tne gun barrel 3 intoJ the` cylindrical casing; 5',.tend Ito/expand laterally to a known extent" aShereinbeOrestated. The shot column then traverses the expansion chamber B and may enterthe compression chamber .fl- BY and thereafter the recompression chamber B-C. The internal diameter of the large end of this recompression chamber is at all times greater than the bore of the gun barrel. In Fig. l of the patent the shot column was shown as greatly expanded when entering the choke tube, but such showing was for demonstration only; in actual practice such is not the case and therefore such showing is an exaggerationi. In practice: it isdeiinitely proven that the shoticoliumn impingeson the surface area Il` at alpoint.l which is so far forward as to be substantially'at the point of entrance to the choke slopelorfarea;a

i2, or practically at point C as'illustratedinLFig." 1 ofthis instant application. Thus, the slopesrli and ii, which are one continuoussmooth` curve= in actual manufacture, arel mainly effective' in:

checking and counteracting thev force ofthe for--` wardly moving gas, and thus counteractrecoil of the gun. By the time the shot columnen'ierges1 from. the choke at point D, the vibration'sihere'- inbefore rnentioned'have been so dampened. that the swing and bend 'errors are negligible and the internal gas pressure'has been reduced,-witl'i1the result that the shot pellets true tothe target. l

In Fig. l the shot wad l5 of theired load is shown well within thechoke chamber C-D -and ahead of the shot column, the shot are shown substantially unexpan'ded within the compression chamber A-B, andthe recompression chamber B'-C is shown functioning to contract4 into alignment and compacted position all of theeX-panded'f shot pellets in the fore portion of theshot column. The usual wad i6, used to separate the'shotfrom the powder charge in the shell, is sh'owny following the shot but, for purposes of illustration' only; it is shown in its original shape and sizeyas herer 1` inbefore stated; its form is greatly changed while traversing the device and actually itileaves thechoke tube at D` in a decidedly broken-up or fragmental-y condition; as has been proved by' spark photographs. The internal diameters of the" choke chamber C-D are such that the-shot' wad l5 will forma substantially mechanical seal or plugin said chamber. While not denitely 'known` just where the greatest damage is doneto' the' powder wad i6, yet it is believed truethat there is a definite mass of the Wad material whichl reaches and enters the choke chamber C-D, which mass' is of sufficient formation to closely contact the walls of said chamber and thus provide an effective seal, so-that the following'gas, still' under relatively tremendous pressure, will.' strike thev sloped'o-r curved surfaces I()A and lli' which, being tapered or curved forwardly' and inwardly, will cause eddyings of said" gas' into whirls creating myriad vortices which constitute'. in effect a gas seal substantially preventing forward travel of further gases into and through the choke tube.

Therefore, the gases are permitted tol escapev laterally fromtliis device through a Vplurality of'v will fly substantiallyI antena;`

, posing all. of these ports above the `horizontal center of the expansion chamber 6, a combinative eiect'of overcoming recoil and preventing climb of themuzzle is obtained. In some instances `it may be desired vto balance such ports as indicated in Fig. l by forming aw substantial duplication thereof, as indicated at I8, in the bottom chamber wall, all of saidports being substantially diametrii cally opposed to each other with reference to an axial `plane of said chamber, and disposed either in the t'op andbottom, or in the sides, of said chamber, as desired. In other instances it may be desired to form such ports as circular holes I9 substantially equally spaced entirely around the chamber wall as indicated in Figs. 3 and 5. still other instances it may be desired to balance only some ofsuch ports Il (or IS) with substantiallyl diametrically opposed ports I8 (or I9), leaving an imperforate section 2U (see Fig. 4) in the wall-of s'aidichamber opposite the unbalanced ports Il (o'r'IS), such imperforate wall section their inner surfaces 26 lie substantially in a cylindrical plane coaxial with the barrel bore, as a result oflwhich the wads l5 and IB form substantial seals successively with such surfaces after leaving the barrel.

Dueto thefact that said ribs are imperforate and relatively closely spaced from each other, these successive seals tend to prevent forward travel of any appreciable quantity of the gases of combustion, and also materially reduce through the exhaust ports the amount of gas pressure which otherwise would reach and become `active in the shot column as said column passes said ribs. Hence, with such minimization or internal gas pressure within the shot column, there is a material reduction in the tendency of the shot'pellets to lateral dispersion, and this reduction is such that the inner cylindricalfsurr`aces`2 ofthe ribs will constitute means for keeping such dispersed pellets from too great a lateral deviation from the axis of flight; this takes into consideration the close spacingof the ribs, the axial extent of their cylindrical surfaces, and the speed of projection of the shot column.

On the side of safety, the rear surface 21 of each rib may be sloped or curved forwardly and inwardly as will be observed from Figs.' l, 4 and '7,

being disposed in that portion of the chamber wall as `will effect the desired lateral movement of the muzzlethrough counteractionof the pressure ofthe gases escaping through the unbalanced ports I'I. The imperiorate wall section 2U may beat either end of the expansion chamber or at va position intermediate of said-ends, and of an extentaccording to the amount of lateral movement desired.` This unbalanced relationship between the total of the top porting and the total of the Kbottom porting may also be accomplished by making provision for more gas to be released through the top ports for example than through the bottom ports, and one way of doing this is to make one'or more of the ports of an area which isgreater than the areaof another port. This is illustrated in Fig. 4a wherein ports I'I and I8 are substantially equal in area and hence are in balanced opposition, but the top port 2l is of 'column when it is ready to leave the expansion chamber to produce the undesirable lateral shot velocities after` leaving the device,and at the same time relieve such an amount of the'pressure from behind the powder wads I6 that said wads will not catch up to and pan-cake the rear end of the shot column.

According to Figs. l, 2 and 3, the expansion chamber I is provided with a plurality of transversely disposed annular ribs 25 supported by the Wall of the casing 5 and extending inwardly of said chamber, said ribs being relatively parallel to each other with a rib disposed between two longitudinally adjacent ports I1, I8 or I9. Each rib has an internal diameter or bore which may be equal to or greater than the diameter of the shot column at such rib, and all of the ribs are 4Substantially similar in construction wherefore and/or may be merged smoothly into the cylindrical rib surface 2B, in order that said rear surface may receive thereagainst any materially laterally dispersed shot pellets, and to turn and direct such pellets inwardly toward the axis of the shot column so as to pass all of the ribs along with the other pellets of said column. Thus, the

ribs serve to maintain the relatively compact formation of the shot column, with concurrent control of the quantity and pressure of the forwardly moving gases, so as to give maximum ef-" feet to the forward drive o-r projection of said column. The ports successively exhaust portionsV of said gases during the travel of theshot column through the device, but the sizes andv shapes, and spacings of the ports in a device may be varied and the total area of all the ports will be kept within proper and desired operatinglimits, to the end that there is sufficient exhaustion of the gases' through the ports to prevent the buildingup of a back pressure in the barrel which might be detrimental upon the next opening of the breech of the gun. Should any pellets become dispersed` after passing the last or most forward rib, the' rear portions ofthe inner surface of. the desired` choke tube willvactthereon, as hereinbefore dis. closed with respect tothe surfaces l0 and II, to, return them tothe body of the shot column.

The construction shown in Fig. 5 is a modiiica-` tion wherein the casing 5 dening the expansion chamber `6 is of a lesser internal diameter, and is provided with a choke tube 8 the inner rearmost surface of which may be outwardly and rearwardly flared (conical or arcuate), or the inner surface of saidtube may comprise a, single conical slope as shown in Fig. 8. In other wor-ds said choke tube, havinga lesser internal diameter, may have a very much reduced compression and recompression chamber area.

The ribs may Lhave such cross-sectional shapes.

sectional shape asvshown in`Figs. land '7j This is evidnt'because when the shot column clearsth'e' anta-1er muzzle offthev `gun barrel it has 'af tendency to exipand laterally due to internal gasipressure; air

pressure or resistance ahead of the colummand because it is no longer'connedby the .barrel wall. When the rear face of the rib is in a plane substantially at right'angles to thedirection of shot projection, as illustrated in Fig. 6, and when the ribdiameterapproaches that of the barrel bore, itis evident that the outer pellets of the expanding. shot column will impingeV on the rear face of the rib adjacent its innermost edge, with consequent damage to such pellets.

.f The cross-sectional shape of ribs shown in Figs...l and?, on the other hand, .provides a rear rib vfacewhich -will deflect the outermost and dispersed pellets back to the shot column Without inicting any serious damage .to saidoutermost pellets, the rear faces of all-the ribs thus performing.

the function of recompressing thev shot column, in successive steps, as the column passes thev ribs or,y in other words, performingv the function of slopes Ill and H of said patent.

In the said patent itis evident that the choking oli and control of the gas takes place at only one pointv viz., in the rearward portion of the choke tube, wherefore a certain amount of gas is bound to leak past the rearmost (or powder) wad and thus enter the shot column. According to the present invention, the series of ribs creates a plurality of relatively short subordinate expansion chambers in the main expansion chamber 6, to the end that a series of substantial gas seals are formed as the shot column and wa'ds pass theribs, and the gas, therefore, is successively valved off to the outside atmosphere through the ports beu tween the ribs, thereby materially reducing the amount of gas whichotherwise would enter the shot column before it enters the rearward portion ofthe choke tube. Each rib is imperforate so that there is no gas communication between such adjacent subordinate chambers.

Coming now to the modifications of this invention illustrated in Figs. 9 to 13 inclusive, it yis pointedout-that these constructions are exemplications of devices which might be more properly applicable to rines or other ordnance capable primarily of discharging a single shot or bullet, as contradistinguished from the devices illustrated inFigs. 1 to 8 and which have been hereinabove described as applicable to a shotgun where plural shot or shot pellets are discharged with one powder charge. However, it is to be distinctly undersoood that thel principles involved in all of the modifications herein illustrated, are substantially the same, particularly with respect to the treatment of the gases, and that. the speciicconstructions illustrated' as well as modications or variations thereof are equally applicable to all. types ofordnance. Therefore, the constructions. shown inFigs. 9 to 13 are vto be considered as improved modifications of those disclosed.. inU.l S.A

Letters Patent No. 1,605,393 granted November 2,v 1926, entitled Climb arrester, and No.. 1,636,357. granted'July 19, 1927, entitled Antilclimb device, bothissued to Richard M. Cutts, Jr.

In general, these modiiied constructions com prise a cylinder '5 creating a main expansion chamber 6, said cylinder disposed. at the muzzle end of' the `gun barrelso that said expansion chamber receives the projectile and the gases of combustion as they leave the barrel. The cylinderA is provided with transversely disposed annular ribs, ports for the escape of the gases'of combustion,'and' a constricted forward" end or projectile Aopening having' suchY an internal diameter as to L8 create a substantialvr gas.'y seali with the projectile when'. thev projectile` is' passing' therethrough.. HncaingeneraLthe statements given hereinbe.- fore with. respectr tothe constructions` shown; in'. Figs.. l to'. 8, .are applicable to the.. modifications. shown in Figs. 94 to` 13; however, the, following; additionalY statements `will be made. since. they.l arci deeme'dit'o berather'pertinent to saidlat`ter modi-t cations. f

According.' toFig., 9. individual or. separatem:- terna'lfannular ribssuch. as 4,.4.| and42 arepro.- Videdwithin the. cylinder 5, said. ribs. having ,thef cylindrical surfaces43., 44 and 45 respectively, but'. these surfaces. are. of diierent diameters,- the. rearmost ribv 4B having the 1argest,1the foremost rib 42 havingthe smallest,.andv the middle rib 4| having a diameter which is `intermediate the; others. In votherwords-the diameters ofthesarib' surfaces successively decrease in the-.directi'onofV` the path of the projectile (represented by thegar-A row)4 through the. cylinders, withthe diameter of the foremost rib. just slightlyv greater than. the bore of the barrel so that when thev projectileA passes-:through the foremost rib,v the projectile. and the cylindrical surface. -'of said rib WilltQg-f gethercreate a substantial gas seal.

Since all of the ribs are. of substantially the. same, thickness where they .loin the wall of the cylinder, and since each rib has atleast one side. surface orv face such as llfwhich is:oblique. to theaxis of the cylinder, it willbe seen that thewidths ofthe cylindrical surfaces 43, 44 and 45v are dif. ferent, decreasingv also in the direction of the path. oi the projectile. Preferably it is the, rearface such as 6G of. each. rib which is made oblique. (though the front face may be similarly formed), the Obliquity being conical or of other formation but inyany event pitched or directed forwardly and inwardly of the cylinder, whereby the for-v wardlyfmoving gases are not completely checkedI by such rear face. but are permitted easement into the chamber space ahead of the rib. However, at the foremost rib 42 the projectile createsa. substantial gas seal with the rib surface 45 when the projectile is passingthrough said. rib, and consequently practically all.. forwardf movement of" gas is stopped'here,A

The forward end o-f this device 'has its inner wall surface 41 forwardly and` inwardly directed. to terminate in the projectile opening 48 just slightly greater than the. diameter of the pron jectile to also create a substantial gas. seal` when. the projectile is passing therethrough. A rela! tively large port 49 isprovided in thev upper wall. portion of the cylinder'5 between the foremost. rib 42 and the projectile opening 48, and-a similar` port 5lis provided to the rear of and adjacent the rearmost rib 40. Between each two ribs therevis provided a port oi smaller areain'the upper wall of the cylinder as indicated at 5l, and

' the bottom Wall portion of the cylinder is imperforate.

AccordingY to Fig. l0 there is a somewhat similar construction, the chief difference being in the fact that two similar large rear po-rts. 55 .are provided instead of the single rear port 50 shown` inFig. 9, in order to permit the escape of a larger quantity of gas and so reduce the amount of gas to be val'veddown by the intermediate. ports 5|.

AccordingY toFig. 11 the single. rear. large. port 5U'i`s provided adjacent the rearmost rib 40, but a relatively small forward port 6U is provided in they placeof` the. largevforward port 49. shown. in Figs. 9`an'd' 10. Al1so,`the're are. but twvorribs pro,

.9 vided in this construction Yand between them there is provided a singlelarge port 6l of substantially the samearea as the rear port 50. Thus, 4the modifications shown in Figs. 10 land 11 are capable in different manners of eiecting the if:

release of substantially the same quantities of gas by the arrangement of port fvalving illustrated, clearly indicating the necessity of relatively Wide latitude in the protection of the principles of this invention.

The construction of Fig. 12 is similar tothat of Fig. 9 insofar as the ribs andports are concerned, but the forward end of the cylinder is provided witha cylindrical inner wall surface 55 instead of the forwardly and inwardly directed wall surface 4T shown in Fig. 9. The diameter of the cylindrical Surface 65 is just slightly greater than the diameter of the projectile, and the length thereof is substantially from the forward port 49 to the end of the device, the purpose of this cylindrical projectile tube or opening being to establish a'gas seal of longer time duration, when the projectile is passing therethrough, than was the case with the construction. shown in Fig. 9.

In Fig. 13 there is illustrated a modification utilizing a single annular rib flanked forwardly with a large upper port 49, and rearwardly with a smaller upper port 5l, this arrangement particularly lending itself to a condition of reduced powder charge, i. e., relatively `low gas pressures, the larger port being providedifor positively valving down the pressure to an amount incapable of ,cocking the projectile while passing through the opening 48.

Therefore, from the constructions shown in Figs. 9 to 13 it will be seenthat the large rear port (or ports) such as 50 and/or 55 will valve `ofl or relieve the major gas pressure to 4prevent `the building-up of undesirable pressure in the gun barrel. The large forward port (or ports) such as 49 facilitate the release of gas not already exhausted by the other ports and, since the projectile (or projectiles such as shot pellets if and a shot-gun)` tends to seal the muzzle of the device when passing throughthe projectile opening, the gas is thus more readily-exhausted through a large port instead of going froward through the `muzzle `or projectile openingthereby resulting in increased efficiency of the device. The number and size, as well as the locations, of the ports may be varied for different installations including variance of powder charge. The determining factor is in the principle of valving-off substantially all of the gas without a build-up of back pressure in the barrel. The intermediate ports, either large or small, may be provided at any and all points where peak pressures occur. 'Ihe constructions of Figs. 9 and l0 are well adapted to handle usual pressures generated by the propellant gas and projectile for normal installations. However, it is known that certain other installations will require the release of the propellant gas at various points along the longitudinal extent of the device at the points where peak pressures occur. It is conceivable that there may be differences in ammunition for the same cali-ber gun, i. e. there may be a difference in the powder charge and the weight of the projectile, wherefore it is to be understood that this invention is flexible in order to cover generally such differences.

In low pressure guns a dead end expansion chamber, such as illustrated in Fig. 12, can be "1'0 used, and the gas is reacted out of the ports. However, in high pressure guns a dead-end alone would create such a terrific impact of forwardly moving gas that the Charpyblow would be materially increased, resulting in a greater strain to the metal of the device, and the report would be more unpleasant to the rer. Therefore, it becomes highly necessary and essential to provide fractional and positive valving ofthe gases by the ribs in conjunction with the ports. In gas porting devices for Shotguns, constructions similar to those shown in Figs. 9-to 13 may be utilized, but it is preferable in such usage -to place the ports in both the top and bottom wall sections of the cylinder. i

It is to be understood that the number, shape, and spacing of the ribs from each other, `as well as the number, shape, spacing, and area of-the ports associated with said ribs1 may be varied in order to so control the heavy gas pressure'as to prevent the said pressure from building-back undesirably or hazardously into the barrel and/,or breech of the gun. Therefore, the constructions shown in the drawings are by way of example only.

What is claimed is:

1. In combination with a shotgun barrel through which shot as well as powder and shot wads are projected by the gases of explosion `,of

a powder charge, a chamber mounted onA the muzzle of the barrel for receiving the gases'j of explosion as well as the projected shot,V said charnber comprising a hollow cylindrical casing having its axis concentric with the axis of the barrel, the inner diameter of said casing being greater than the bore of the barrel, said casingfthereby forming a chamber space toipermit expansion of the gases therein, the wall of said casing having longitudinally spaced apertures'toy release f-.a portion of the expanded gases of explosion laterally of the casing, said wall also provided: with a plurality of separated substantially similar annular, radially inwardly extending ribs providing a projectile opening in each rib, said ribs forming separate subdivisions of the expansion.' chamber, at least one rib disposedbetween two'. of said longitudinally spaced wall apertures', and the projectile opening through each rib formedfof a diameter such as to provide a substantial gas seal with the projected powder and :shot wadsas the wads pass the ribs, the rear face of each rib so sloped forwardly and inwardly to said projectile opening as to turn such stray shot, as may impinge thereagainst, inwardly toward the axis of the shot column, Y

2. A device for attachment to the forward end of a shotgun barrel for porting the gases of explosion received from the barrel and for receiving shot as well as powder and shot wads projected through the barrel by the gases of explosion of a powder charge, said device comprising a, hollow cylindrical member to be concentric with the axis of the barrel when attached thereto, the inner diameter of said member being greater than the bo-re of the barrel, said member thereby forming a chamber space to permit expansion of the explosion gases received therein, the member having wall portions so formed that when the member is attached to the shotgun barrel the side wall portions of said member will be imperforate and the top and bottom wall portions thereof will each have longitudinally spaced apertures for releasing a portion of the expanded gases of explosion laterally of the member, said member also provided with a plurality of separated annular,

fenenei nadiallyiinwartily extendlngiribs; each 'ribprovid- 'ingf; a,.'projectile fopening, said .ribs forming fseparateesubdiyisionsrol the :expansion ychamber, at :.least'v one :rib vdisposed between. two oft-said longitudinallly spacetifwall apertures,.andfthe :proje'cfho'l'low generallycylindrica'l ymember "having Aan 5:,

internal fdiameter greater than the bore 'f the 'gunSybarre'lto thereby provide a chamber -space to "permit fthe expansion of the explosion `fgases =recived therein, the memberhavingwallportions so formed that when the member is attached lto -Y .the shotgun barrel the side Wallfportions'ofsaid lfmerriberwill'be imperforate'andthe top and botltom wall portions thereof-will -eaclfiihave a -plureality-'ef :apertures ffor releasing abortion of the u"expanded A'gases of yexplosion Ilaterally of said imeniber, ratleast two `of said apertures beingv 'clis- 'posed fon :opposite lsides y.of a 1longitudinal faxial @lane of Ysai-'cl 1 member :and being intercepted :by #a 'common transverse f plane-at right fangles f to the 'axisfdf saidvmember, said wallfa'lso Aprovidedinteiriorlyithereof withsanfannular, radially extending erbxformlng separate subdivisions of vthefexpansion 'dirarnber,:said rib disposed .between .twofoffsaid :apertures and fthe fzopening 'through said rib formed fof :a :diameter such Izas fto provide .a sub- .rstantial :seal with the .rproiected powder and asmtmadsaasfthewads Vpass fsaidtrib, .the Yrearface cof isaid :rib :so fsloped :forwardly :and inwardly :to theneroiec'tile opening as .to f turnzsuch -stray f shot, innay --irrrpinge drhere'against, inwardly 4toward ithe axis yinf thefs'mtcolumn.

54. Q'Afdeviceforiattachment .to :the forward end fofafr'shotgun barrelfor porting ,the gasesiofcexplofsion .deceived (from the barrel and ffor `.receiving .sshohaswwell fas lpowder "and eshot wad/s projected i2 through the barrel by f the' ygases of explosion -of -ia-fpowder'chargevsaid device-comprising a hollow lgenerally cylindrical member to be concentric -withithe'faxisof Athe barrel'fwhenattached thereto, `the vinner '.iiameterfof said member being-greater r`.than-theajourefof the barrel, said member thereby Yforminga chamber space tcpermit expansion'of theexplosiongases received therein, the member having'wall `portions so formed 'that when the member is attached to the shotgun barrel thezside wall portions fof A.said .member will be -imperfcrate end the top'andsbottom -wallportionsthereof will each have longitudinally spaced vapertures -for rel-easing ai portion of `the'expanded gases'of'ex- .pl-osion laterallyy ofzt-he member, said 'memberialso ,provided 'with an annular, radially inwardly v.ex- .tendinggrib providing la projectile vopening, said Yrib forming-separatesubdivisions of .the'expansion .chamben ',saidrib -`disposed between vtwo of Said longitudinally spaced'wall aperturesand the gproiectile openingkthrouggh said rib formed -ofa .diameter isuchsas to provide aisubstantiahgas seal with :the .projected `powder rand shot wads :as the fwads pass tt'herib. i


@REFERENCES fCITED The lfollowing vreferences are Aof record vin 'the le of vthis patent:

UNITEDST-ATES PATENTS vNumber lName y Date "785;'975 Mc'Clean `Ma,r. Y28, 1905 317,134 Smith Apr. :3, 1906 981,584 Miller Jari. '10, 1911 :1,427,802 Goodwin sept. l'5,v 1922 A-1,T 9`8360 Pavek .'Aug. 31, 1926 Lfll'l fSte'inegger i 'Nov.2,"1926 1;773260 lCutts 'Aug. 19,1930 1,801,258 '-BaT-ker A131121, 1931 1,939,700 "Hoifstettel Dec. 19,-'1933 vv'2,'15615511557 'Cutts July'l-l, 1939 C22-,3131569 Raising 'Mar/9, '1943 "2322,370 Lance June 252, 1943 `2,34'8;1-I4 Dow -May 2, 11'944 52153982298 :Finlay Apri-9,1946

FOREIGN PATENTS Number Country yDate v293;'553 :Germany -Feb. 15, y1917

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U.S. Classification89/14.3, 42/79
International ClassificationF41A21/40, F41A21/00, F41A21/36
Cooperative ClassificationF41A21/36, F41A21/40
European ClassificationF41A21/36, F41A21/40