US2447205A

US2447205A - Shotgun muzzle device

Info

Publication number: US2447205A
Application number: US593881A
Authority: US
Inventors: Powell Edward Baden
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-05-15
Filing date: 1945-05-15
Publication date: 1948-08-17
Anticipated expiration: 1965-08-17

Description

Patented Aug. 17, 1948 NITED STATE P This invention has reference to devices of the type known as compensator-type chokes for shotguns: the general purpose and object of the in- }vention is to provide better control of shot pattern than has heretofore been achieved, to attain higher shot velocities than have been practicable with known compensator-type chokes, to minimize recoil and to control or reduce muzzle jump and muzzle blast of the gun. These and other objects, together with the corresponding accomplishments of the invention will appear in the following.

Shot-gun compensator-type chokes commonly in present use embody a cylindric perforated cage which projects forwardly from a-shortened gun barrel, with a choke tube mounted in the forward end of the cage and projecting forwardly from it.

The cage is of larger diameter than the barrel and is of such length that the rear'or pickup" end of the choke tube is commonly located several inches forward of the barrel muzzle. The gap between the barrel muzzle and the choke tube is considerably longer than the total length of the shot charge and the following wad; so that the wad leaves the gun muzzle before the shot charge enters the rear or pick-up end of the choke tube. The high pressure gases which are released when the wad leaves the muzzle may thus flow forwardly through the cage around the shot charge and, travelling at higher velocity than that charge, enter the choke tube ahead of the charge. In that action the high velocity gases tend to disturb the solid mass arrangement of the shot. Also the shot charge tends to expand laterally as soon as it leaves the muzzle and must be gathered together, or laterally recompressed by the pick-up end of the choke tube.

The general result is that, although a considshot gun chokes of the types now in use (cages with longitudinal or circumferential slots distributed around the cage wall, or with an even distribution of perforations around the wall) may be used with my inside type choke tubes. However I prefer to provide a cage of a design here- 2 inafter described for the purpose of minimizing recoil and muzzle jump.

The choke tube of my choke device is mounted in the forward end of the cage but extends rearwardly from that forward end toward the gun muzzle, leaving only a short annular gap between the gun muzzle and the rear end of the choke tube. This short annular gap provides an escape port for a controllably limited amount of the high pressure, high velocity; ases, which then flow forwardly around the choke tube and find ultimate exit through the opening or openings in the cage wall, in the manner which will be described. The gap between gun muzzle and choke tube may be varied in its axial dimension, but in every case it is always much shorter than the total axial length dimension of the shot charge and wad. Infact, this gap dimension will not ordinarily be much if any longer than the axial dimension of the wad. In any event, the shot charge always enters the choke tube a substantial distance, if not for the whole length of the shot charge, before the wad leaves the muzzle. The wad thus effectively holds back the high velocity gases which would otherwise tend to by-pass the charge if the charge had not en: tered the choke tube by the time the wad leaves the muzzle; the charge is thus kept in a compact mass and the high velocity gases which are not laterally relieved follow the shot charge and wad through the choke tube. This followin action, together with the fact that with my relatively short choke device the gun barrel itself may be longer than is commonly the casewith the pres ent long choke devices, gives the shot charge a materially higher muzzle velocity than is at present achieved with chokes. Also, the shortness of the gap afiords the shot charge very little opportunity to spread laterally, and consequently, the shot charge does not have to be recompressed laterally, with attendant disturbances of the mass and deformation of pellets, upon entering the.

' choke tube.

The invention will be more fully understood from the following detailed description or a preferred embodiment shown in the accompanying drawings in which Fig. 1 is a longitudinal central section showing my present preferred form of choke mounted upon the end of a shot gun barrel, this figure showing the charge in a position entering the choke tube;

Fig. 2 is a similar view showing the charge and wad in the choke tube, and

Fig. 3 is a cross-section on line 3-3 of Fig. i.

. in the drawings the muzzle end portion of a shot gun is shown at it, the extreme muzzle end being designated by the numeral H. The muzzle end is provided externally with screw-threads l2, or any other suitable attaching means by which the tubular cage i5 is mounted upon the muzzle end of the barrel to project forwardly therefrom in the manner shown. The case as here shown has a cylindric wall l6 with an opening I! at one side only. The purpose of. this single opening through one side only of the wall will be explained later. But, as I have said, wall I 6 of the cage may be equipped with final outlet openings of any suitable type, character, and

pattern. As here shown, outlet I! is of elongated rectangular form.

The outer end of cage i5 is internally screwthread'ed at til, or otherwise formed for the convenient mounting of the choke tube which is generally designated by the numeral 2|. As here shown, the choke tube is provided, at or near its outer end, with threads matching the threads 20, and with a shoulder 22 which may be butted against the outer end of case it. The choke tube extends rearwardly or inwardly in the cage, and its inner end, designated by the numeral 23, is located at a relatively short distance from muzzle end I l of the barrel, so that an annular escape port of limited'axial length is provided between the muzzle end and inner end 23 of the choke tube. The internal diameter of the main bore 25 of the choke tube is preferably the same as that of the bore of barrel ill. The choke formatlon, shown at 26 at the forward end of the choke tube may be of any desired configuration, and choke tubes with different choke configurations may be substituted in the cage.

As shown in the drawings, the internal diamstar of cylindric cage i5 is substantially larger than the bore diameter of the gun and also substantially larger than the external diameter of choke tube 2!. Thus, an annular passage 21 is left between cage wall i6 and the exterior of the choke tube, that annular passage being closed at its forward end by the shoulder which is shown at 28. Outlet opening I I has its outer end at that shoulder 28, and has its inner end 29 in about the same transverse plane as the inner end 23 of choke tube 2 I.

Without limiting my invention thereto, I give the f ollowing typical dimensions for my choke device as applied to a 12-gage shot gun. The drawlogs are approximately full scale for that size of gun. For such a gun, which has a bore of about 0.75", the internal diameter of cage I5 is here shown as being about 1.25". The length of the cage from muzzle end H to shoulder 28 is shown as about 3%; the total length of the choke tube is about 3 /2, the gap between the barrel muzzle and the choke tube is shown as being 0.5" and the outlet port H as being about 0.75" Wide and about 2%" long. The maximum external diameterof the part of the choke tube which defines one wall of annular passage 27 is about 1", making that annular passage have a radial dimension of about Va". The well of the choke tube may be tapered in thickness from its threads to the inner end 23, as shown.

Fig. 1 shows how the shot charge of any ordinary volume (say about 1" in length) will bridge the annular gap at G so that the shot charge has entered some distance forwardlyinto the rear end of choke tube 2i while the wad W is still in gun barrel ii). Thus, before wad W leaves the gun barrel, shot charge S has almost completely, if

not completely, entered the choke tube and has effectively sealed the choke tube against being by-passed by the following gases from the gun barrel.

Fig. 2 shows shot charge 8 and wad W completely in the choke tube, and with the annular opening or port at G completely open. As soon as wad W leaves the muzzle end II, the following gases begin to now laterally through the annular gap at G and into the annular passage 21 between cage wail l6 and choke tube 2|. The proportionate part of the gases which flow through the annular gap and flow outwardly through annular passage 21 is determined and controlled by the length .of gap G. The gases which do not flow through gap G follow the charge and wad through the choke tube, adding velocity to the charge.

The gases which do flow through the annular gap at G flow forwardly through annular passage 21 and laterally toward the outlet port H, in much the pattern of flow which is indicated by the arrows in Fig. 2. The forwardly flowing gases are turned laterally by the shoulder 28, and the forward longitudinal force which is thus exerted on that shoulder tends materially to diminish the recoil action of the gun. Finally, the lateral flow of the gases through port I! tends to move the gun muzzle laterally in the opposite direction. By placing the device upon the gun in such a position that outlet port I! is upward (that is, port I! is at the top of the device when in use) the lateral reaction of the escaping gases is in a downward direction and tends very materially" to minimize the upward jump of the gun muzzle.

As has been indicated, the proportionate amount of the gases released through the annular gap at G depends upon and is controlled by the axial length of that gap; and that axial length may be proportioned to release a lesser or lar er fraction of the whole gaseous charge. However,

, in any case, the axial length of G is always considerably less than the total axial length of shot charge S and Wild W, so that the gases cannot by-pass the shot charge. The area of the annular gap at G having been determined (inthe present design that area is something over twice the circular area of the barrel bore) then the total area of outlet port I! is made to ,be about the same as the area at gap G, or somewhat substantially larger. As here shown the annular area of the port at G is about 1.18 sq. in. and the area of port I1 is about 2 sq. in. And the cross-sectional area of annular passage 21, as here shown, may preferably be substantially smaller than the total area at annular gap G, so that the gases flow forwardly through annular passage 2'! at a fairly high velocity to be turned laterally by the shoulder at 28. As shown, the cross-sectional area of the annular passage is about the same as that of the gun bore or of the interior of the choke tube at its rearward end-0.442 sq. in.

' I claim:

1. A muzzle device for firearms of the shot gun type discharging a scatter shot charge, which includes a substantially tubular cage, means for mounting the rear end of said cage on and surrounding the muzzle of a gun barrel to which the device is designed to be attached, a shot pattern control tube supported and extending longitudinally within said cage and adapted to terminate in spaced relation from the muzzle end of the' 70 following wad normally designed for the gun, said aeeaaoe d cage and tube being constructed and arranged to provide a passage extending longitudinally between them and in open communication with said gap, and outlet means in the wall of said cage leading exteriorly from said passage to the atmosphere.

2. A muzzle device as specified in claim 1 in which the wall of said shot pattern control tube is imperforate.

3. A muzzle device as specified in claim 1, comprising means for supporting said shot pattern control tube at a location near the forward end of said cage and for closing the forward end of said passage.

4. A muzzle device as specified in claim 1, in which the wall of said shot pattern control tube is imperforate, said tube having threaded engagement within the forward end of the cage, an integral forwardly facing shoulder on the cage, and a rearwardly facing shoulder on the tube engageable against said cage shoulder.

5. The combination comprising a shot gun barrel, and a muzzle device carried by the barrel, said device including a substantially tubular cage having its rear end secured to and about the muzzle end of said barrel, a shot pattern control tube supported within said cage substantially in alinement with the barrel and terminating in spaced relation from the muzzle end of the barrel to form a gap the length of which is not more than the total axial length of a shot charge and following wad designed for the gun, said cage and tube being constructed and arranged to provide a passage extending longitudinally between them and in open communication with said gap, and outlet means in the wall of said cage leading exteriorly from said passage to the atmosphere.

6. A muzzle device as specified in claim 5, also including means for detachably securing the shot pattern control tube at a location in the forward end portion of the cage and from which the tube projects rearw-ardly toward the barrel.

'7. A muzzle device as specified in claim 5, in which said shot pattern control tube is imperferate, and further including a threaded connection between the tube "and forward end portion of the cage, and an annular shoulder on the tube engageable against the cage.

8. A muzzle device as specified in claim. 5, in which said tube is imperforate and is supported only within the forward end portion of the cage.

EDWARD BADEN POWELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,080,154 Moore Dec. 2, 1913 1,860,276 De Luce et a1 May 24, 1932 1,901,138 Barnes Mar. 14, 1933 1,939,700 Hofstetter Dec. 19, 1933 2,112,831 Cutts Apr. 5, 1938 2,348,114 Dow May 2, 1944 2,372,315 Catron Mar. 27, 1945