US3233546A

US3233546A - Shotshell design

Info

Publication number: US3233546A
Application number: US341339A
Authority: US
Inventors: Donald S Foote; Justin H Whipple
Original assignee: Remington Arms Co LLC
Current assignee: Remington Arms Co LLC
Priority date: 1964-01-30
Filing date: 1964-01-30
Publication date: 1966-02-08
Anticipated expiration: 1983-02-08

Description

l "eb- 8, 1936 D. s. Foo-rE ETAL 3,233,546

SHOTSHELL DESIGN Filed Jan. 30, 1964 2 Sheets-Sheet 1 F@ fig. z, Hg. J

la 22C ZZ Feb- 8, 1966 D. s. FooTE ETAL 3,233,546

SHOTSHELL DESIGN Filed Jan. 30, 1964 2 Sheets-Sheet 2 7776/? /4 'I ornegs.

United States Patent Ofiee 3,233,546 Patented Feb. 8, 1966 3,233,546 SHTSHELL DESIGN Donald S. Foote, Greens Farms, and Justin H. Whipple,

Milford, Conn., assigner-s to Remington Arms Company, Inc., Bridgeport, Conn., a corporation of Delaware Filed Jan. 30, 1964, Ser. No. 341,339 7 Claims. (Cl. 102-42) This invention relates to improvements in shotgun shells and more specically to an improved, low-cost plastic shotshell.

Although plastic shotshells have been known for some time, it is only recently that they have been available in large commercial quantities. The advantages of plastic shotshells over paper .or metal shotshells has been discussed at length in trade publications, prior patents, etc. and need not be discussed here. The great majority of plastic shotshells available on the market today, however, have high tensile strength and have their molecular structure oriented, as explained in Patent Number 3,103,- 170, issued to R. A. Covington et al. It can be appreciated that considerable effort and expense is involved in making such high tensile strength plastic shotshells.

A major problem with the economical, injection-molded type of plastic shotshell has been tearing or stretching of the shotshell body caused by indentation of the relatively soft plastic by the shot pellets which upon ring move forwardly and radially to drag the body and cause tensile failure.

The figures show several variations of thick-wall-clam closure design. All of the shotshell designs exhibit a common princi-ple in that the great majority of shot pellets are outside of the shotshell body. In order to accomplish this design change without violating shotshell loaded length specifications, it is necessary to use a shell casing of far shorter length than present conventional designs.

In a magazine-fed shotgun, especially the automatic type, the fired shell casing, in addition to being extracted from the chamber, must be completely ejected from the breech. If this is not accomplished, the extracted shell will obstruct the feeding of the next round into the charnber, dsereby preventing the firing of a second shot. Although shotgun ejection means vary considerably from gun to gun, in general the shell is withdrawn from the chamber by the extractor attached to the bolt, and is struck on the opposite side of the rim from the extractor as the bolt approaches its most rearward position. The energy from the blow causes the tired shell to pivot about the extractor, releasing itself from the extractor and ejecting from the port provided in the shotgun receiver. The eiectiveness of this action has been found to cor-relate with the tired shell center-of-gravity location. Considerable testing involving thousands of rounds has shown ejection failures with shells possessing a center-of-gravity approx. .500 orl more from the face of the head to occur very ra-rely in any other than defective guns. When the center-of-gravity figure falls below the .500 value the Ifrequency of ejection failures begins to increase. The .500 figure, however, should not be considered a sharp line of demarcation between successful shell eiection and ejection failure. For example, a shell with a center-of- Vgravity location .460 from the face of the head will function satisfactorily in many guns, but experience has shown that the frequency of failures in occasional guns in the field will be high enough to result in an excessive number of customer complaints. Still lower center-of-gravity locations result in a higher yfrequency of ejection failures in a greater number of guns. This required center-ofgravity location restriction would prohibit the simple shortening of a conventional shell casing. For this reason, a thick-wall. shell casing must be utilized in order to compensate for the center-of-gravity change caused by shortening the shell length.

At the present time, a conventional shotshell comprises a body casing Whose unloaded length is approximately 23/4 although magnum loads utilize casings up toapproximately 3" long. Paper casings generally have a Wall thickness 4of approximately .030 although plastic casings on the market generally vary from about .017 to .035". In general, a conventional shotshell would include a metal head, usually either brass or steel.

By utilizing a zinc die cast head as shown in FIGURE l and fully explained in Patent Number 3,099,958, issued to B. K. Daubenspeck et al., it is possible to decrease the overall casing length to approximately 1.700" and increase the wall thickness to approximately .125 in order to locate the center of gravity of the empty shotshell about .500 from the face of the head, the minimum distance required for satisfactory shell ejection.

FIGURES 3-6 show the use of a light plastic head, preferably Delrin By reducing the head weight, it is now possible to shorten the shell casing even furthe-r (to about 1.450) while still maintaining the .500 center-ofgravity location. If desired, however, the shell length with the plastic head can be left the same as with the zinc die cast head, and a reduction in wall thickness to approximately .080 can be made with the same resultant center-of-gravity location. This thickness, however, is still substantially greater than present conventional shotshells, as explained above. y

Although brass or other metal heads can be used, economics seem to favor a zinc die cast head or the light plastic head. Obviously, with a heavier metal head, the center-of-gravity problem with a shortened body casing becomes more serious thus necessitating either a longer shell or a heavier wall thickness.

In addition to providing a low cost, reloadable shell, the present invention also includes all of the advantages generally associated with the use of shotliners. Thus, the shot container effectively prevents the shot from becoming deformed while being explosively projected through the gun barrel, since the shot liner prevents the -shot `from coming in contact with the barrel. Barrel leading thus, also is decreased. Finally, by keeping the shot pellets togetherpuntil after the shot container leaves the barrel and the liner hinges to fall away from the shot, more uniform and consistent patterns are achieved. This is more fully explained in copending application Number 306,026, led September 3, 1963.

It is the object of Vthis invention to provide an economical injection-molded plastic shotshell which will function satisfactorily in present-day Shotguns.

It is another object of this invention to provide a lowcost` plastic shotshell having a body casing which has a considerably shorter length and a thicker wall portion than conventional shotshell bodies.

It is another object of this invention to provide a shotshell in which the major portion of the shot is outside the shotshell body casing.

It is still another object of this invention to provide a shotshell having a unitary member which functions as a cushioning means-shot container-closure means.

It is still another object of this invention to provide a shortened shell having increased body wall thickness Which permits the shortening of the shell Without sacrificing the center-of-gravity location required for satisfactory shell ejection.

Other objects and advantages will be obvious from reading the accompanying specification, claims, and drawings in which:

FIGURE l shows an elevational view of a shotshell incorporating the invention having a zinc die cast head and designed to accommodate a shot load of approximately 11A; ounces of shot.

FIGURE 2 shows a shotshell similar to FIGURE 1 except that the cushioning means is changed to accommodate a shot load of approximately 1%. ounces of shot.

FIGURE 3 shows an elevational view of a shotshell utilizing a light plastic head and a shot load of 1% ounces.

FIGURE 4 is similar to FIGURE 3 except that the shot load is 1% ounces.

FIGURE 5 shows a modiiied shotshell wherein the cushioning means is not lnnged and the shot load is ll/s ounces.

FIGURE 6 is similar to FIGURE 5 except for a 1% ounce shot load.

FIGURE 7 shows a hinged cushioning-container-closure member in an opened position.

FIGURE 8 shows a cross-sectional view of line 8 3 in FIGURE l.

Two types of closure-shot containers are shown in the drawings. Both are specifically designed for the thickwalled shotshell in that both have a section which tits into the relatively small shell inside diameter and an expanded portion outside of the shell which is sur'iiciently large to seal the shotgun bore, thus, preventing leakage of the powder gases past the shot container.

In each of the iigures, a shotshell 10 is shown to include a body casing 12 made by injection molding a low tensile strength plastic. In one particular injection molded linear polyethylene plastic used to make shotshells under the present invention, the tensile strength was between 800() to 9000 p.s.i. A casing having this low tensile strength will ordinarily tear olif at the mouth upon ring, so that reloading of the shell is impossible. Actually, linear polyethylene plastic up to about 17,000 p.s.i. longitudinal tensile strength will generally exhibit some degree of mouth cut oi'f, especially when hard shot is used.

Body casing 12 is open at the mouth end 14 and closed off at the rear by a head portion 16. In FIGURES 1 and 2, the head portion 16 is made of Zinc molded integrally with the body casing as explained in Patent Number 3,099,958. A primer cavity 13 is formed in the head and a primer 20 inserted therein.

Inserted in the mouth end of the shotshell body casing and held therein by means of an interference tit, is a unitary, molded cushioning-shot container-closure member 22 made of plastic `or any other suitable material. Unitary member 22 includes a reduced diameter cushioning section 24 whose diameter is slightly larger than the inside diameter of the body casing 12, so that the cushioning section 24 can be pushed into the open end of the body casing and held there by means of an interference lit, a snap-on or some other means. An enlarged outer shot container-closure portion 26l has at least a section of its portion of a suciently large diameter to seal the shotgun bore. In FIGURES 1-4, the portion outside the casing proper has a diameter substantially the same as the outside diameter of the body casing. Obviously, the entire portion outside the body casing 12 need not be the same diameter as the body casing.

Unitary member 22 comprises two half sections 22a and 22h, connected together by a hinge 23 and adapted to have portions 24a and Zlib over-lap to provide a lower support means for the shot pellets 30. One half section may be provided with a skirt (22C) on each side which overlaps the inside edge of the other half, thus providing a means to prevent side movement of one section with respect to the other, as well as aiding in preventing any leakage of powder gases into the shot column.

The upper end of body casing 12 has a narrow lip 32 formed thereon which is flexible enough to be forced against the bore of the barrel to act as a gas seal.

Upon tiring, the propellant powder 34 ignites and ex- CIK plosively projects unitary member 22 out of the shotshell body casing and through the shotgun barrel. Upon leaving the barrel, the two

half sections

22a and 22b open up and pivot about hinge 28 and fall away from the enclosed shot load. The shot pellets 30, which have been protected from the heat of the gas as well as the abrasive action of the gun barrel, are free to move in their own trajectories towards the target without any interference from any shell front end crimp or top wad or by any shot container which may get in the way of the shot pellets.

FIGURE 2 shows essentially the same as FIGURE 1 except that the cushioning section 224 has been modified in order to accommodate more shot pellets.

The shotshell of FIGURE 3 is essentially the same as FIGURE l except that a light plastic head 316 is substituted for the zinc head 16. Head 316 is attached to the shotshell body casing 312 by means of a threaded projection 34 which screws into the lower breech end of the body casing 312. An opening 36 in the threaded projection 34 holds a primer 35 which differs somewhat from primer 20.

Body casing 312 is shorter than `casing 12 because the decrease in the weight of the head 316 permits less casing weight to balance the head weight in locating the centero-gravity the required distance from the face of the head. Thus, the coniiguration of cushioning section 324 varies slightly from its counterpart 24.

FIGURE 4 is essentially the same as FIGURE 3 except that cushioning section 424 has been revised slightly to permit accommodation of a greater shot load.

r[he body casing and head of FIGURES 5 and 6 `are the same as FIGURES 3 and 4. However, FIGURE 5 shows a modied cushioning-shot container-closure means. Instead of having a unitary member which performs all three functions, FIGURES 5 and 6 show two separate elements, a lower cushioning section S24, which again has a reduced diameter in order to t and be held within the open mouth end of body casing 312, and a shot container-closure member 40, which is similar to the clam closure disclosed in copending application 306,026. The lower cushioning section 524 includes an end portion 42 which flares outwardly from the reduced diameter portion to provide the necessary diameter to properly seal the gas from escaping past the slightly narrower containerclosure member 40. The upper container-closure member is detachably connected to the lower cushioning section 524 by a groove and detent means 44. It should be appreciated that the cushioning section can be attached to the container-closure section on the inside 4as well as on the outside, as shown. In either case, it is necessary to provide a section having surlicient diameter (about as much as the diameter of the body casing) in order to properly seal and prevent the explosive gases from escaping around the outside of the shot container-closure member.

FIGURE 6 is similar to FIGURE 5 except that the cushioning section 624i has been modied to accommodate a greater shot load.

FIGURES 5 and 6 each show the lower cushioning section to be solid, i.e., non-hinged. The shot containerclosure 40 includes a slit means 46 which extends down opposite container-closure walls and across the top of the front end closure member 48. An unslit portion 50 is left on each side to act as hinge means.

Upon being explosively projected out of the gun barrel, the container-closure member 40 opens up like a clam shell to pivot on hinge means 50 and permit the enclosed shot pellets to proceed uninterruptedly on their way towards the target.

It is obvious that other modifications can be made incorporating the inventive concept explained herein.

What is claimed is:

1. A shotshell comprising a thick-walled plastic shotshell casing, said casing having an open-ended mouth at one end and a head at the opposite end thereof, a cornbination shot container-closure cushioning means having a lower cylindrical section including a cushioning means which is inserted within the open-ended casing mouth to interference fit the inside diameter of the thick-walled shotshell casing, and a closure portion attached to said lower cylindrical section and projecting forwardly of said casing, said lower cylindrical section and closure portion dening a cavity therein in which a plurality of shot pellets are positioned so that the major portion of the ellets are located outside of the casing mouth prior to ring, said thick-walled plastic shotshell casing having a wall thickness of at least about .080" so that the centerof-gravity of the empty shotshell is located approximately .500 or greater from the rear end of the shell head in order to facilitate red shell ejection from automatic Shotguns.

2. A shotshell as recited in claim 1 wherein said plastic shotshell casing is made of a soft, injection-molded plastic which experiences stretching or tearing of the shell body when the shot pellets, upon firing, indent the soft plastic, upon moving forward to drag the body and cause tensile failure.

3. A shotshell as recited in claim 1 wherein said combination shot container-closure-cushioning means includes two hinged longitudinal sections and means on the longitudinal edges of said hinged sections to limit transverse movement of one section relative to the other and to prevent leakage of powder gases into the shot column.

4. A shotshell comprising a thick-walled plastic shotshell casing having an open-ended mouth at one end and a zinc die cast head at the other end, shell closure-shot container means which includes a tubular section of sufliciently large diameter to seal the shotgun bore, and a cylindrical section of lesser diameter than said tubular section which fits the inside diameter of the thick-walled shotshell casing, said shell casing having a shortened length which cooperates with said shell closure-shot container means to position the great majority of shot pellets outside of the shell casing, said shell casing having a wall thickness of about 0.125, said thick-Walled structure cooperating with said zinc head and the shortened plastic casing to locate the center of gravity of the empty shotshell about 0.500 from the zinc head.

5. A shotshell comprising a thick-walled plastic shell casing having a tensile strength less than about 17,000 p.s.i. whose mouth end would ordinarily cut off upon firing a conventional load of shot pellets, a head portion at the rear end of the shell casing, means confining a plurality of shot pellets and positoned so that the great majority of the pellets are located beyond the month end of the casing, said means including a tubular section of sufiiciently large diameter to seal the shotgun bore and a cylindrical section of lesser diameter than said tubular section which fits the inside diameter of the thick-walled shotshell casing, said thick-walled casing having a wall thickness of at least about 0.080 depending on the length of the shell casing and the material of which the head portion is made, the inal determination of head portion material, casing wall thickness, and casing length designed to position the center of gravity of the empty shotshell at about 0.500 from the rear end of the head portion.

6. A shotshell comprising a casing made of a plastic material having a tensile strength less than about 17,000 p.s.i. whose mouth end would ordinarily exhibit some degree of body mouth cut oi upon tiring a conventional load of shot pellets, a head portion connected to said casing, a preassembled shot container-olosure-cushioning means inserted and releasably held within the mouth end of said casing and extending outwardly therefrom so that the large majority of shot pellets is positioned outside of the casing mouth, said casing having a length ranging from about 1.450-1.700" and wall thickness of between about 0.08 -0.l25" in order to position the center of gravity of the empty shotshell casing and head portion approximately about 0.500 from the head portion.

7. A shotshell as recited in claim 6 wherein said preassembled shot container-closure-cushioning means comprises a lower cushioning section having an end portion to which a container-closure member is detachably secured.

References Cited by the Examiner UNITED STATES PATENTS 3/1880 Coloney 102--42 8/1963 Daubenspeck et al. 102-43 X

Claims

1. A SHOTSHELL COMPRISING A THICK-WALLED PLASTIC SHOTSHELL CASING, SAID CASING HAVING AN OPEN-ENDED MOUTH AT ONE END AND A HEAD AT THE OPPOSITE END THEREOF, A COMBINATION SHOT CONTAINER-CLOSURE CUSHIONING MEANS HAVING A LOWER CYLINDRICAL SECTION INCLUDING A CUSHIONING MEANS WHICH IS INSERTED WITHIN THE OPEN-ENDED CASING MOUTH TO INTERFERENCE FIT THE INSIDE DIAMETER OF THE THICK-WALLED SHOTSHELL CASING, AND A CLOSURE PORTION ATTACHED TO SAID LOWER CYLINDRICAL SECTION AND PROJECTING FORWARDLY OF SAID CASING, SAID LOWER CYLINDRICAL SECTION AND CLOSURE PORTION DEFINING A CAVITY THEREIN IN WHICH A PLURALITY OF SHOT PELLETS ARE POSITIONED SO THAT THE MAJOR PORTION OF THE PELLETS ARE LOCATED OUTSIDE OF THE CASING MOUTH PRIOR TO FIRING, SAID THICK-WALLED PLASTIC SHOTSHELL CASING HAVING A WALL THICKNESS OF AT LEAST ABOUT .080" SO THAT THE CENTEROF-GRAVITY OF THE EMPTY SHOTSHELL IS LOCATED APPROXIMATELY .500" OR GREATER FROM THE REAR END OF THE SHELL HEAD IN ORDER TO FACILITATE FIRED SHELL EJECTION FROM AUTOMATIC SHOTGUNS.