US3565008A

US3565008A - Plastic shotshell and method

Info

Publication number: US3565008A
Application number: US740185A
Authority: US
Inventors: Ronald A Gulley; Robert J Klein; Vernon C Moehlman
Original assignee: Olin Corp
Current assignee: Olin Corp
Priority date: 1968-06-26
Filing date: 1968-06-26
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23
Also published as: FR2011986A1

Abstract

A shotshell including a plastic tube and a one-piece plastic basewad-overlay disposed in the tube, the basewad-overlay having a boss on the rear face thereof and the tube having a radially inwardly turned rear edge portion extending toward the boss, with a portion of the tube extending radially out be captured within a flange formed on a metallic head element of the shotshell and then continuing under the basewad to mate with the boss portion.

Description

I United States Patent 35654108 [72] Inventors Ronald A. Gulley [56] References Cited Jenning UNITED STATES PATENTS 3,424,089 1/1969 Humpherson 102/43 3,442,214 5/1969 Huskins 102/42 Appl' M FOREIGN PATENTS [22] Filed June 26, 1968 [45'] Patented Feb. 23,1971 1,193,324 3/1958 France 102/95 [73] Assignee Olin Mathieson Chemical Corporation Primary Examiner koben F Stab] Attorneys-Donald R. Motsko, H. Samuel Kieser, William W.

Jones, Richard S. Strickler, Robert H. Bachman and Thomas P. ODay ABSTRACT: A shotshell including a plastic tube and a one- [54] PLAS TIC SHOTHEIYL AND METHOD piece plastic basewad-overlay disposed in the tube, the 4 Clams 5 Drawmg basewad-overlay having a boss on the rear face thereof and [52] U.S. Cl 102/43, the tube having a radially inwardly turned rear edge portion 102/44 extending toward the boss, with a portion of the tube extend- [51] Int. Cl F92b 5/30 ing radially out be captured within a flange formed on a metal- [50] Field of Search 102/42,42 lic head element of the shotshell and then continuing under (C), 73, 44 the basewad to mate with the boss portion.

PATENTEDFEBwsn 3. 565008 INVENTORS. RONALD/4. GULLEY ROBE/PT J KLEIN VERNONCMOEHLMAN BY MMMQrM.

ATTORNEY [[6 4 FIG '5 PLASTIC SHOTSIIELL AND METHOD This invention relates to a shotshell having a plastic tube, a plastic one-piece basewad-overlay and a metallic head element, which shotshell permits superior reloadability and exhibits excellent gas-sealing properties, acceptable head pull characteristics, and resistance to deteriorating effects of hot combustion gases.

In the ammunition industry, substantial efforts have been directed toward the development of a shotshell having a plastic tube to replace the conventional paper tube due to the fact that plastic shotshell tubes permit superior quality and quality control, provide for lower production costs, and allow standardization of manufacturing techniques. While numerous shotshells having plastic tubes are contained in the prior art, such prior art plastic shotshells have been found to be, for the most part, commercially nonfeasible due to performance which has proven inferior to the conventional paper shotshell.

One area wherein the prior art plastic shotshells have been found to be particularly substandard is the reloadability thereof. The prior art plastic shotshells have been formed with conventional paper or fibrous basewads and separate paper or fibrous overlay wads, which wads are deleteriously affected by hot combustion gases and flame-produced when the shotshell is fired. Such wads are burned when the shotshell is fired and therefore must be frequently replaced when reloading in order to provide a safe and reliable reloaded shell. Replacement of the wads is expensive and time consuming, and often cannot be accomplished without a complete refabrication of the entire shell.

In order to overcome the above-noted damaging effects upon the basewad and overlay wad caused by hot combustion gases and flame, the prior art discloses a plastic shotshell having a composite basewad composed of a sawdust or other fibrous core with a comparatively thin plastic overlay connected thereto, as shown in US. Pat. No. 3,157,121 to Benjamin Daubenspeck et al. This type of prior art plastic shot shell has been found to possess undesirable characteristics relating to performance when the shell is fired. The force which acts to retain the basewad in the shell is the press fit of the basewad in the plastic tubing which is in turn held in place by the metal head. The obturation of the thin-skirted overlay portion of the basewad to the tube wall also aids in this respect. The opposing force, or head pull, which tends to pull the basewad out of the shell is caused by a vacuum which develops behind the moving shot charge as the latter leaves the shell and proceeds through the barrel of the gun. To properly resist this force, the head must be firmly connected to each of the other components of the shell. When the shotshell is fired, forces are developed which tend to propel the basewad and/or the overlay wad into the barrel of the shotgun. The head of the shotshell is the only element which tends to retain the basewad and overlay wad in the shell tube. The head element is sized onto the basewad, overlay wad, and tube to firmly connect the components together, In order to achieve a satisfactory connection, considerable force is applied to the exterior of the head during the heading operation. The composite basewad of the US. Pat. No. 3,157,121 to Daubenspeck et al. has shown undesirable weakness when exposed to the sizing forces, which weakness has been attributed to the fibrous core of this basewad. Similar undesirable weakness has been noted when heading a plastic tube shell having a paper or other compacted fibrous basewad.

Still another disadvantage of the prior art composite basewads used in plastic shotshells is their unsuitability for comparatively cold weather shooting. It has been found that the plastic coating, as well as the sawdust inner core, on the composite basewad of the prior art is subject to cracking when fired in colder temperatures, such as below about F.

This invention provides a plastic shotshell which exhibits superior reloadability, excellent gas-sealing properties, acceptable resistance to head pull, and resistance to the deleterious effects of hot combustion gases and flame. The shotshell of this invention includes a unitary basewad'overlay preferably formed from a solid body of high-density polyethylene plastic. The basewad includes an integral feathered skirt portion operative to obturate the combustion gases generated when the shell is fired. The basewad-overlay includes a centrally located longitudinal passage for receiving a primer or battery cup, and further includes a boss formed on the rear face of the basewadcverlay. The basewad-overlay is press fitted into a plastic tube, the latter of which has a rearward edge which is turned inwardly and curled back upon itself so as to underlie the rear face of the basewad-overlay and extend toward the boss. The shotshell further includes a metallic head which is fitted onto the exterior of the tube in the area of the basewadoverlay. The head is sized onto the tube and flanged in posi tion so that a portion of the tube adjacent to the inwardly turned edge thereof is squeezed radially outwardly into the head flange to be captured thereby. When the shell is headed, the inwardly turned edge of the tube is also squeezed against the basewad-overlay and retained between the head and the basewad-overlay. Since the basewad-overlay is preferably formed from a solid body of high-density polyethylene plastic, it is able to endure, without failure, the forces directed thereagainst when the head is sized and flanged onto the tube. The shell has been consistently fired at temperatures as low as -20 F, without cracking or rupture of the basewad-overlay.

It is, therefore, an object of this invention to provide a shotshell having a plastic tube and a plastic basewad-overlay, which shotshell exhibits superior reloadability.

It is a further object of this invention to provide a shotshell of the character described which is resistant to the deteriorative effects of hot gases and flame.

It is yet another object of this invention to provide a shotshell of the character described which exhibits acceptable resistance to head pull.

It is still another object of this invention to provide a shotshell of the character described which displays excellent obturation of combustion gases.

Other objects, features, and advantages of this invention will become apparent to one skilled in the art upon examination of the following detailed description, when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional elevation of a portion of a shotshell formed in accordance with this invention;

FIG. 2 is a cross-sectional elevation of the rearward portion of the shotshell of FIG. 1 showing the shotshell before the head has been sized and flanged on the tube;

FIG. 3 is an exploded view ofthe various elements shown in FIG. 2;

FIG. 4 is a perspective view of the basewad-overlay with sections cut away to more clearly show the internal details thereof; and

FIG. 5 is a side elevation, partially in section showing the assembly of FIG. 2 as the head is sized and flanged on the tube, and showing the squeezing of the tube into the head flange to be captured thereby.

Referring now to FIG. 1, a preferred embodiment of a portion of a shotshell formed in accordance with this invention is shown. The shotshell, denoted generally by the numeral 2, includes a plastic tube 4, preferably formed from oriented highdensity polyethylene fabricated in a conventional manner. By high density," it is contemplated that the polyethylene have a density in the range of, for example, about .940-.96O gm/cm.*. The lower or rearward edge portion of the tube 4 is turned radially inwardly as at 6 with the terminal portion thereof being turned back upon itself, as at 8. A unitary basewad-overlay 10 having a tapered gas obturating skirt 12 is disposed in the tube 4. A boss 14 is formed on the rear or lower face of the basewad-overlay 10 and an axial passage 16 is disposed in the basewad-overlay 10 to receive a primer cup 18. A propellant charge 20 is disposed in the basewad-overlay 10 with wad means 22 overlaying the propellant charge 20. The wad 22 shown as being preferred for use in the shotshell of this invention is of the type disclosed in U.S. Pat. No.

3,285,174; however, it is understood that other wads may be 1866 in place thereof without departing from the spirit of this invention. A charge of shot 24 is disposed in the tube 4 above the wad 22 in a conventional manner. A metallic head element 26 is mounted on the rearward end of the shell 2, the head 26 including a basal flange 28 in which a portion 30 of the tube 4 is captured.

Referring now to FIG. 2, an assembly stage of the shell 2 is shown, wherein the basewad-overlay 10 has been inserted into the tube 4, and the tube 4 and basewad-overlay 10 have been inserted into the head 26, the latter of which includes a partially formed flange 28. FIG. 3 is an exploded view of the assembly of FIG. 2 which more clearly shows the configuration of the rearward end of the basewad-overlay 10, and the rearward edge portion of the tube 4. It is noted that the boss 14 formed on the rearward face of the basewad-overlay 10 is inwardly offset from the sidewall of the basewad-overlay to define a shoulder 15. It is further noted that the rearward edge portion of the tube 4 is turned radially inwardly at 6 with the terminal portion 8 thereof curled back upon itself. Upon assembly, the inwardly turned edge portion 6 of the tube 4 is sandwiched between the rear face of the basewad-overlay 10 and the bottom wall ofthe head 26.

FIG. 4 is a perspective view of the basewad-overlay l having a portion thereof cut away for purposes of clarity. The basewad-overlay is a unitary member formed, preferably, from a solid body of high-density polyethylene. The upper, or forward end of the basewad-overlay includes a tapered annular thin-walled skirt 12 which obturates by action of combustion gases, flaring outwardly against the wall of the tube 4 when the shell is fired. The middle portion of the basewadoverlay 10 includes a comparatively thick-walled propellant cut 32 having a frustoconical inner wall 34. An aperture 16 is axially disposed in the basewad-overlay, to receive a primer cup (see FIG. 1). The boss 14, formed on the rear face of the basewad-overlay, is preferably outwardly spaced from the rim of the aperture 16 and inwardly spaced from the outside wall of the basewad-overlay.

FIG. 5 shows the heading operation in which the head 26 is sized onto the shell. The partially formed shell of FIG. 2 is disposed on a supporting member 36 and moved into a female die 38. The head 26 is then sized and flanged by moving the die 38 and the supporting member 36 together in the direction of the arrows 40 so as to cause the die 38 to press the head 26 onto the tube 4 and basewad-overlay 10. As the head 26 is compressed and flanged, frictional contact between the head 26 and the tube 4 causes the rearward end of the latter to be squeezed radially outwardly, as at 30, into the head flange 28. The tube 4 is thus firmly retained at the portion or flange 30 by the head flange 28, and at the radially inwardly turned flange 6 by being sandwiched between the head 26 and the rear face of the basewad-overlay 10. Furthermore, the provision of a solid plastic basewad-overlay permits the use of higher heading pressures to be used in the fabrication of the shell.

It is thus apparent that a shell formed in accordance with this invention displays superior reloadability due to the fact that the shell is more resistant to the deleterious effects of firing. The solid plastic basewad-overlay provides resistance to hot combustion gases, and flame, stability at low-firing temperatures, and strength not found in the prior art basewad structures. The positive double interlock between the tube and the head flange on one hand, and the tube, the head, and the basewad-overlay on the other hand provides superior resistance to head pull not found in the prior art plastic shotshells.

Although reference has been made to a particular embodiment of the present invention, various modifications will readily suggest themselves to those skilled in the art and reference should be made to the appended claims to determine the scope of the invention.

We claim:

I. A shotshell comprising:

a. plastic tube means; A b. a unitary basewad-overlay member contained within said tube means, said member having a cylindrical sidewall and a projecting boss formed on a rear face thereof, said boss forming a shoulder inwardly spaced from said sidewall of said member;

c. a metallic head element mounted on said tube means,

said head element having a basal flange; and

d. said tube means including a rearward end comprising a first radially inwardly extending portion having a terminal portion curled back upon itself to form a double thickness said radially inwardly extending portion and said curled back portion being squeezed between said head element and said basewad-overlay member and against said shoulder, and a second radially outwardly extending portion of said tube means being captured by said head flange.

2. The shotshell of claim 1, wherein said basewad-overlay member is composed of a solid piece of polyethylene having a density of about .940 to .960 grams per cubic centimeter.

3. A shotshell comprising:

a. a high-density polyethylene tube having an inwardly turned rearward edge, said inwardly turned rearward edge having a thickness which is substantially greater than the thickness of the remainder of said tube;

b. a unitary, high-density, solid polyethylene basewad-overlay member disposed in said tube, said member including a projecting shoulder closely adjacent to said inwardly turned edge of said tube;

c. a metallic head element sized onto said tube about said basewad-overlay member, said head element having a flange; and

d. said inwardly turned edge of said tube being trapped between and squeezed by said basewad-overlay member and said head against said shoulder, and said head flange being operative to capture a portion of said tube.

4. A shotshell comprising:

a. a plastic tube means having a constricted rearward opening formed by an inwardly extending part on said tube, said part having a thickness which is approximately twice the thickness of the remainder of said tube;

b. basewad-overlay means disposed in said tube means, said basewad-overlay means comprising a boss projecting through said constricted rearward opening and snugly gripped by said thicker tube part; and

c. head means sized on said tube, said head means being operative to fasten said tube means to said basewad-overlay and squeeze said thicker tube part against said boss, and said head means including a flange operative to capture a portion of said tube means.

Claims

1. A shotshell comprising: a. plastic tube means; b. a unitary basewad-overlay member contained within said tube means, said member having a cylindrical sidewall and a projecting boss formed on a rear face thereof, said boss forming a shoulder inwardly spaced from said sidewall of said member; c. a metallic head element mounted on said tube means, said head element having a basal flange; and d. said tube means including a rearward end comprising a first radially inwardly extending portion having a terminal portion curled back upon itself to form a double thickness said radially inwardly extending portion and said curled back portion being squeezed between said head element and said basewad-overlay member and against said shoulder, and a second radially outwardly extending portion of said tube means being captured by said head flange.

3. A shotshell comprising: a. a high-density polyethylene tube having an inwardly turned rearward edge, said inwardly turned rearward edge having a thickness which is substantially greater than the thickness of the remainder of said tube; b. a unitary, high-density, solid polyethylene basewad-overlay member disposed in said tube, said member including a projecting shoulder closely adjacent to said inwardly turned edge of said tube; c. a metallic head element sized onto said tube about said basewad-overlay member, said head element having a flange; and d. said inwardly turned edge of said tube being trapped between and squeezed by said basewad-overlay member and said head against said shoulder, and said head flange being operative to capture a portion of said tube.

4. A shotshell comprising: a. a plastic tube means having a constricted rearward opening formed by an inwardly extending part on said tube, said part having a thickness which is approximately twice the thickness of the remainder of said tube; b. basewad-overlay means disposed in said tube means, said basewad-overlay means comprising a boss projecting through said constricted rearward opening and snugly gripped by said thicker tube part; and c. head means sized on said tube, said heaD means being operative to fasten said tube means to said basewad-overlay and squeeze said thicker tube part against said boss, and said head means including a flange operative to capture a portion of said tube means.