Plastic Shotshell With Sealing Rings

Abstract

A plastic shotshell case to be loaded with powder and shot charges and wads separating the shot and powder; the plastic case having peripheral ribs or rings at the exterior adjacent the open mouth of the case and effectively sealing the case wall against the shotshell chamber in the barrel of the shotgun; the exterior peripheral surface of the case wall being smooth at a location forwardly of the sealing ribs.

Description

BRIEF SUMMARY OF THE INVENTION

The plastic shotshell case with a plurality of outwardly projecting rings or ribs extending peripherally of the case adjacent the open mouth or closure end of the case that function principally at the instant of firing, at which time the rapidly burning powder gases are expanding and creating extremely high gas pressures within the shotshell case and the shotgun barrel. At this instant, the gas pressure forces the case wall outwardly and causes the rings to engage and seal against the barrel wall to prevent gas from escaping in a rearward direction along the exterior surface of the case and adjacent the breech bolt of the shotgun.

The plastic shotshell case is formed by injection molding of plastic; and may be formed principally of polyethylene plastic; or it may be desired to form the shotshell case principally of a polycarbonate plastic.

The exterior peripheral surface of the shotshell case wall is striated in a longitudinal direction throughout a major portion of the length of the shotshell case wall; and at locations forwardly of the rings, the polyethylene case wall has its exterior peripheral surface smooth and unbroken for a distance of approximately half the diameter of the tubular shotshell case for forming the star crimp closure of a shotgun shell after the shell is loaded with the shot, powder and wads. The smooth exterior peripheral surface at this portion of the shotshell prevents or minimizes through numerous loadings and reloadings of the shotshell case, splitting of the case due to repeated folding in the numerous reloads and formations of the star crimp for enclosing the interior of the shotshell case.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged elevation view of the plastic shotshell case.

FIG. 2 is a greatly enlarged detail section view taken approximately at 2--2 in FIG. 1 and showing the relative size relationship between the ribs or rings and the case wall and the relationship between the several ribs along the case wall.

FIG. 3 is an elevation view at a reduced scale of the shotshell which is partly broken away for clarity of detail and shown applied into the shotshell chamber of the barrel of a shotgun and retained by the breech bolt, the details of the breech construction of the shotgun barrel are mostly eliminated.

FIG. 4 is an elevation view of a modified form of plastic shotshell case wherein the closure is formed by a top wad.

DETAILED DESCRIPTION OF THE INVENTION

The plastic shotshell case is indicated in general by numeral 10 and is formed by injection molding. The shotshell case is integrally formed in one piece, and the entire shotshell case is formed in one molding process so that the entire case is integral and all portions of it are of the same material. The shotshell case may be formed of polyethylene plastic, and may have small quantities of other types of plastics mixed in with the polyethylene to obtain certain strength and other characteristics. Likewise, it may be desirable to form the all plastic shotshell case 10 of a polycarbonate plastic, either a pure polycarbonate or possibly with other plastics mixed in to give the plastic certain characteristics. It will be understood that polycarbonate plastic is very hard and withstands high impact, and has been successfully used in the production of such shotshell cases, which are subsequently made into shotgun shells for hunting and other types of shooting.

The shotshell case 10 has a base portion 11 and an ejecting flange 12, and an elongate tubular case wall 13 terminating at its front end 14 in an open mouth through which the ejectable components of the shotshell, including the shot charge, powder charge, the wads, etc., are loaded into the shotshell case for forming the shotshell. Of course, the case is closed at the base 11 and a primer is mounted in the base for ignition of the powder charge upon firing the shotshell in a shotgun. Along a major portion of the case wall 13, the exterior peripheral surface of the case wall is striated as indicated at 15. The striate texture of the exterior peripheral surface contributes to ease and comfort of handling the shotshell case and the shotshells which are eventually made therefrom, and to give the shotshell case a pleasing appearance.

The forward portion 16 of the tubular case wall 13 is smooth at its exterior peripheral surface for a distance along the length of the case from the open mouth equaling approximately half the diameter to facilitate the formation of a star crimp in the smooth surfaced front end portion 16. It will be understood that in the formation of a star crimp the front portion 16 of the case wall is folded numerous times in an accordian pleat type shape around the periphery of the case wall so that upon forming the star crimp and upon the repeated formations of star crimps and the opening of the crimps under force of the shot and gas pressures in the shotshell case, there is some tendency for the case wall to split because of the folding. However, the smooth exterior peripheral surface of the portion 16 of the case wall adjacent the open mouth where the star crimp is formed tends to minimize the likelihood of there being any splitting of the shotshell case in spite of numerous reloadings of the polyethylene shotshell case. It has been found that a shotshell case such as that disclosed herein may be reloaded eight to ten times without splitting the shotshell case in the vicinity of the front end portion 16 even though the star crimps are formed a like number of times.

At the exterior peripheral surface of the case wall 13, the portions 15 and 16 are separated by a plurality of outwardly projecting cylindrical rings or ribs 17 on the exterior periphery of the case wall. The ribs or rings 17 project only a very small distance from the peripheral face of the case wall, so that these ribs 17 will not interfere with the normal handling and usage of the shotshell case during loading of the case and during insertion of the loaded shotshell into the barrel 20 of a shotgun or the removal of the expended or emptied case from the barrel. The ribs 17 have a thickness or height in a radial direction only approximately one-tenth the thickness of the case wall. The width of each of the ribs 17, in a direction longitudinally of the case wall, is of the same order as the thickness of the case wall in the vicinity of these ribs. The spacing between the ribs 17 is of the same order of dimensions as the width of these ribs. It is preferable that the forwardmost rib 17 is disposed a sufficient distance from the open mouth end 14 of the shotshell case so that the entire star crimp can be formed in the end portion 16 of the case wall without distorting the forwardmost rib 17.

When the shotshell case is properly loaded with powder, wads, shot, and the case is closed for firing, the loaded shotshell 19 may be inserted into the shotshell chamber of the shotgun barrel and be retained therein by the breech bolt 21 in a well known manner. The firing of the shotshell causes instant ignition of the powder in the shotshell case and development of high gas pressures due to the combustion and expansion of the powder gases as the shot charge is suddenly set into motion along the gun barrel and toward the muzzle end. As the gas pressures in the shotshell case build up, the shotshell case wall 13 expands very slightly against the interior surface of the shotshell chamber of the barrel 20 and the ribs 17 produce a highly efficient seal between the shotshell case 13 and the barrel 20 so as to prevent powder gases, or other materials such as unburned powder, from escaping in a direction rearwardly along the case wall 13. and toward the breech bolt 21. The seal produced by the ribs 17 bearing against the barrel effectively prevents the loss of gas pressure in a reverse direction and, as a result, all of the gas is effectively utilized for acceleration and propulsion of the shot charge toward the muzzle of the barrel.

In the form of shotshell 25 illustrated in FIG. 4, the shotshell case 26 has a plurality of sealing ribs 17' identical to those illustrated in FIGS. 1 - 3. In this form of the shotshell case 26, the case wall 13' terminates just forwardly of the forwardmost rib 17', as indicated at 14', and this forward edge of the shotshell case wall 13' is simply rolled over slightly to retain the end wad or closure wad 27 applied within the periphery of the case wall and over the shot confined in the shotshell 25.

As previously described in connection with FIGS. 1 - 3, the ribs 17 serve to seal the case wall 13' against the shotgun barrel to prevent high pressure gases from traveling or leaking rearwardly along the shotshell case upon ignition.

It will be seen that I have provided a new and improved all plastic shotshell case with sealing ribs extending peripherally adjacent the mouth end of the case wall to seal against the shotshell chamber of the shotgun barrel upon firing of the shotshell when high pressures are developed through expansion of powder gases. The plastic shotshell case also has a smooth and unbroken exterior peripheral surface in the forward portion of the case wall which is utilized for the star crimp so as to contribute to the continued life of the shotshell case through numerous reloadings without splitting at the forward star crimp portion of the shotshell case.

Claims

What is claimed is:

1. A shotshell case comprising,

a tubular case wall constructed of plastic, the case wall having a front closure end from which the shot charge exits upon ignition of the powder charge,

and a plurality of external circumferential ribs on the case wall and formed integrally thereof adjacent the closure end, said ribs having a thickness in a radial direction several times less than the thickness of the case wall, said ribs being engageable with the barrel wall to seal against the barrel and prevent gases under pressure from escaping along the case wall and toward the breech bolt of the shotgun only upon firing the shotshell and ignition of the powder therein.

2. The shotshell case according to claim 1 and said ribs having a width in a direction along the case wall on the same order as the thickness of the case wall.

3. The shotshell case according to claim 2 and said ribs being spaced from each other by a distance of the same order as the width of the shells.

4. The shotshell case according to claim 1 and said case wall being constructed of plastic consisting to a large degree of polycarbonate.

5. The shotshell case according to claim 1 and said case wall being constructed of plastic consisting to a large degree of polyethylene.

6. The shotshell case according to claim 1 and the case wall extending toward the front well beyond the circumferential ribs and sufficiently to produce a closure by a star crimp.

7. The shotshell case according to claim 1 and the case wall terminating immediately forwardly of the ribs to receive and retain an end wad to effect the closure.

8. The shotshell case according to claim 6 and the exterior surface of the case wall at locations forwardly of and rearwardly of the ribs being respectively smooth and striated in a longitudinal direction.