US3359906A

US3359906A - Shotshell base wad

Info

Publication number: US3359906A
Application number: US514935A
Authority: US
Inventors: George L Herter
Original assignee: Herter's Inc
Current assignee: Herter's Inc
Priority date: 1965-12-20
Filing date: 1965-12-20
Publication date: 1967-12-26
Anticipated expiration: 1984-12-26

Description

Dec. 26, 1967 G. l.. HERTER 3,359,906

SHOTSHELL BASE WAD Filed DSG. 20, 1965 INVENTOR.

A waal/e745 United States Patent O 3,359,906 SHOTSHELL BASE WAD George L. Herter, Waseca, Minn., assignor to Herters Inc., Waseca, Minn., a corporation of Minnesota Filed Dec. 20, 1965, Ser. No. 514,935 2 Claims. (Cl. 102-95) ABSTRACT F THE DISCLOSURE A base wad for use with a shotshell including a generally cylindrical body formed of a plastic material having a concave front end to receive the powder charge therein and having a base end with a radially extending flange projecting outwardly therefrom and defining a cushioning pocket between the base and shotshell head. A primer pocket in the body extending axially from the base end and a smaller opening extending axially from the front end and communicating with the primer pocket to define a shoulder overlying the primer cap positioned in the primer pocket. A plurality of sealing and cushioning elements integrally formed with the body and projecting radially outwardly therefrom throughout the length thereof engaging the inner circumferential surface of the shotshell to form a seal thereat and to produce a cushioning effect when the base wad is subjected to pressure forces produced by a detonated propellant charge.

This invention relates to firearm cartridges and more particularly relates to an improved base wad for shotshells.

In the construction of shotshells it is desirable to use a base Wad inside the head of the shotshell to keep the powder or propellant charge disposed in front of the flashing end of the primer as well as to hold the primer cap to the brass base and prevent gas from leaking out of the primer hole or base at detonation. Several methods have been attempted to properly carry out this function. Several types of base wads have been tried including a hollow plastic base wad lled with paper. This construction was not successful in that gases escaped into the primer cap area upon detonation. This results in greatly reduced efficiency in the use of the propellant charge. Paper base wads have been successful to some extent. However, all of the wads known to date have presented the problem of not properly sealing the gases generated by the explosion of the propellant charge within the propellant charge chamber. The gases must be sealed from expanding either into the shot cup area, thereby destroying the pattern pof the shot, or from expanding into the primer cap area, thereby decreasing the eiciency of the propellant charge. Gases which escape into the shotshell head may also destroy or distort the head of the shell, preventing its reuse by hand loaders.

With these comments in mind it is to the elimination of these and other disadvantages to which the present invention is directed along with the inclusion therein of other novel and desirable features.

An object of my invention is to provide a new and mproved base wad of simple and inexpensive construction and operation.

Another object of my invention is the provision of a base wad which seals gases from the head of the shotshell case and from the primer cap area.

Another object of my invention is the provision of a base wad which, upon detonation of the propellant charge, maintains a seal without distorting the head of the shotshell and without cracking -or otherwise deforming the base wad.

A still further object of my invention is the provision of a base wad which disposes the powder or propellant charge properly within the propellant charge chamber in front of the primer cap while allowing the proper amount of primer flash to escape from the flashing end of the primer cap into the propellant charge.

These and other objects and advantages of -rny invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIG. 1 is a partial longitudinal sectional View taken along a plane through the center of the shotshell.

FIG. 2 is a partial longitudinal sectional view taken along a plane throughout the center of the shotshell at the precise time of detonation.

FIG. 3 is a perspective view showing the base wad of -my invention as it appears separate from the shotshell,

FIG. 4 is an elevation of the base wad of my invention with a breakaway portion showing the primer pocket sealing and cushioning elements.

FIG. 5 is a longitudinal sectional view taken along a plane through the center of the shotshell showing an alternate construction of my base wad and an alternate as sembly of the base wad and shotshell.

FIG. 6 is a partial perspective view showing an alternate base wad with sealing and cushioning elements projecting downwardly from the powder engaging surface.

FIG. 7 is a partial perspective view showing an alternate base Wad with sealing and cushioning elements projecting outwardly.

FIG. 8 is a partial longitudinal sectional view taken along a plane through the center of the base wad and showing sealing and cushioning elements directed downwardly into the primer pocket.

FIG. 9 is a partial longitudinal sectional View taken along a plane through the center of the base wad and showing sealing and cushioning elements directed upwardly into the primer pocket.

The base wad of my invention is shown in FIG. 1 and is indicated in general by numeral 10. Ba-se wad 10 is of molded construction and formed from compressible resilient plastic material such as polyethylene. Considerably harder plastic formulations may also be utilized to achieve optimum operating characteristics or Variations in performance. The base wad is shown assembled in a generally tubular plastic or paper shotshell engaging the casing side wall 11a of the shotshell 11. A tubular brass head 12 is shown surrounding the shotshell and includes a brass base 13 generally circular in shape and having a recessed area 14 to receive a primer cap 15. The primer cap is inserted axially into the recess 14 and through aperture 15b in the base 13. The shotshell includes a base portion 16 in contact with the base portion 13 of the brass head 12 and includes an aperture 17 in registry with the recess 14 and aperture 15b of the base 13 of the brass 3 head 12. The primer cap is inserted with the flashing end 17a forward toward the propellant charge or powder 17b. Any of the conventional over-powder wads may be disposed above the powder 17b to define and seal the propellant or powder chamber.

Referring to FIG. l, base wad 10 includes a lower, substantially annular fiange or skirt portion 18 which projects downwardly and contacts the inside surface of the shotshell case 11. Flange 18 defines a cushioning recess between the base 16 of the casing and the lower transverse surface of the base wad 10. An axial primer pocket 20 is included in the base wad and is adapted to receive the primer cap 15. Axially spaced, substantially annular inner sealing and cushioning elements 21 engage the primer cap 15 providing a seal thereto. Aperture 22 communicates with the primer cap 15 at the flashing end 17b thereof, disposing powder 17b at the ashing end of the primer cap 15. A transverse annular shoulder 23 engages the primer cap 15 at the ashing end thereof and effects a seal therebetween. Substantially annular, radially projecting, axially spaced sealing and cushioning elements or convolutions 24 are included on the outer periphery of the base wad 10. The sealing and cushioning elements 24 engage the side walls 11a of the case providing a seal thereto. The sealing and cushioning elements have a saw-tooth cross-section with the teeth extending generally upwardly toward the propellant charge 17b. The teeth are typically reslient and yieldable, springing back into position after detonation.

The upper portion of the base wad 10 includes radially projecting, axially spaced rings 24 surrounding a powder chamber 25 generally defined by the concave walls extending from the top of the base wad downwardly to the aperture 22. The powder chamber encloses powder which interconnects the propellant charge 17b with the flashing end 17a of the primer cap 15. Aperture 22 is of a diameter smaller than the diameter of the primer cap 15 yet large enough to permit the primer flash to communicate with the propellant charge 17 b, thereby detonating the propellant charge, while continuously maintaining a seal at shoulder 23 between the powder chamber and the primer pocket 20.

Referring to FIG. 3, flange 18 is shown projecting downwardly from surface 19. Aperture 17, which receives primer cap 15, is shown with one of the sealing and cushioning elements 21. The outer sealing and cushioning elements 24 are indicated at 24. Referring to FIG. 4, the break-away view shows the opening for the primer cap 15 and shows the sealing and cushioning rings 21 which engage the primer cap 15. Upwardly projecting sealing and cushioning rings 24 engage the walls of the shotshell 11. Flange 18 is shown projecting downwardly defining the cushioning recess between the base wad and the shotshell.

The operation of the base wad of my invention is best described by referring to FIG. 2. At the precise point of detonation, the base wad of my invention is placed under extreme pressure. In fact, the entire shotshell is placed under pressure from the explosive force of the propellant charge which has been detonated by the primer cap. The pressure forces the base wad 10 downwardly toward the base 13 of the shotshell. Since the teeth 24 project upwardly, the base wad may move downwardly without difficulty and without destroying the seal. The sealing and cushioning elements are also forced outwardly at the point of detonation since the base wad is put under compression, increasing the diameter of the wad. Since the sealing and cushioning elements are spaced axially, the seal is maintained between the casing and the base wad at the time of detonation with additional sealing obtained from the outward force of the base wad on the shotshell casing. The sealing and cushioning elements are yieldable and resilient, absorbing the shock between the wad and casing and springing back into position after detonation. Rings 21 engage the primer cap maintainng a seal at ths point. At detonation the diameter of the wad primer pocket is Cal decreased and the seal becomes tighter without distorting the wad since the rings 21 absorb the shock between the primer cap and the primer pocket. Additional sealing is effected at flange 23 from the tight fit between the cap 15 and the flange 23. When detonation takes place the pressure forces flange 23 downwardly into sealing engagement with the priming cap 15. After the pressure has been absorbed the base wad springs back into position since it has been cushioned from the adverse effects of the explosion. The casing and base wad may now be reloaded since there has been no adverse effect on them from firing.

An alternate embodiment of my invention is shown in FIG. 5. A plastic shotshell casing is indicated at numeral 26. A base wad 27 is shown with skirt or fiange 28 crimped to the rim of the brass head 29. This secures the base wad to the shotshell casing, while maintaining the sealing and cushioning effect of the base wad of my invention. The primer cup 30 fits snugly within the primer pocket 31, at detonation, the pressure exerted on the base wad are absorbed by the outer sealing in cushioning elements 32.

FIG. 6 shows an alternate base wad having sealing and cushioning elements or teeth 33 projecting downwardly from the powder engaging surface 34, adapted to seal with the inside periphery of the shotshell casing.

In FIG. 7, an alternate base wad is shown having sealing and cushioning rings 35 projecting outwardly from the powder engaging surface 36, to form a seal with the casing of the shotshell.

A partial sectional view of an alternate base wad is shown in FIG. 8 and shows internal sealing and cushioning convolutions or teeth 37 disposed at the primer cap 38. Sealing and cushioning convolutions 37, which project downwardly form a seal between the base wad and the primer cap preventing gases from escaping upon detonation of the shotshell.

Another embodiment of my invention is shown in FIG. 9 which shows sealing and cushioning rings 39 disposed internally at the primer cap 40 projecting upwardly toward the powder charge. Rings 39 form a seal between the primer cap and base wad and also tend to hold the primer cap upwardly in position against the powder charge.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.

What is claimed is:

1. A base wad adapted to be seated within and corporate with the head of a shotshell, said base wad comprismg:

a generally cylindrical plastic body having a base end and a concave front end to receive a powder charge therein,

an annular fiange integral with said base end and projecting radially outwardly and slightly axially therefrom and delining with said base end a concave cushioning pocket between the base end and shotshell head,

a primer in said body extending axially from said base end for receiving a primer cap therein,

said body having an opening therein extending axially from said concave front end and communicating with said primer pocket, said opening being of a substantially smaller cross-sectional size than said primer pocket to define an annular shoulder for overlying the end of a primer cap in the primer pocket,

said body having a plurality of similar sealing and cushioning elements integrally formed therewith throughout the length thereof and projecting out. wardly from the exterior surface of said body and adapted to engage the inner circumferential surface of the shotshell, each of said elements being equally spaced apart and disposed in closely proximal relation to each adjacent element to define a plurality of closely spaced apart outwardly opening grooves of References Cited substantially the same size whereby said elements UNITED STATES PATENTS may be readlly urged towards each other to form a seal with the inner surface of the shotshell and to 97,537 12/1869 Logan 1oz-44 produce a cushioning effect thereat when the base 5 /Ionhamt--l dbtdt ayerea Wa 1s su )ec e o pressure forces produced by a 3,246,603 4/1966 Comerford 1oz-42 detonated propeller charge.

2. The base Wad as defined in claim 1, wherein said cushioning elements and grooves extend outwardly and BENJAMIN A' BORCHELT Prlmmy Exbmmer upwardly. 10 ROBERT F. STAHL, Examiner.

Claims

1. A BASE WAD ADAPTED TO BE SEATED WITHIN AND CORPORATE WITH THE HEAD OF A SHOTSHELL, SAID BASE WAD COMPRISING: A GENERALLY CYLINDRICAL PLASTIC BODY HAVING A BASE END AND A CONCAVE FRONT END TO RECEIVE A POWDER CHARGE THEREIN, AN ANNULAR FLANGE INTEGRAL WITH SAID BASE END AND PROJECTING RADIALLY OUTWARDLY AND SLIGHTLY AXIALLY THEREFROM AND DEFINING WITH SAD BASE END OF CONCAVE CUSHIONING POCKET BETWEEN THE BASE END AND SHOTSHELL HEAD, A PRIMER IN SAID BODY EXTENDING AXIALLY FROM SAID BASE END FOR RECEIVING A PRIMER CAP THEREIN, SAID BODY HAVING AN OPENING THEREIN EXTENDING AXIALLY FROM SAID CONCAVE FRONT END AND COMMUNICATING WITH SAID PRIMER POCKET, SAID OPENING BEING OF A SUBSTANTIALLY SMALLER CROSS-SECTIONAL SIZE THAN SAID PRIMER POCKET TO DEFINE AN ANNULAR SHOULDER FOR OVERLYING THE END OF A PRIMER CAP IN THE PRIMER POCKET, SAID BODY HAVING A PLURALITY OF SIMILAR SEALING AND CUSHIONING ELEMENTS INTERALLY FORMED THEREWITH THROUGHOUT THE LENGTH THEREOF AND PROJECTING OUTWARDLY FROM THE EXTERIOR SURFACE OF SAID BODY AND ADAPTED TO ENGAGE THE INNER CIRCUMFERENTIAL SURFACE OF THE SHOTSHELL, EACH OF SAID ELEMENTS BEING EQUALLY SPACED APART AND DISPOSED IN CLOSELY PROXIMAL RELATION TO EACH ADJACENT ELEMENT TO DEFINE A PLURALITY OF CLOSELY SPACED APART OUTWARDLY OPENING GROOVES OF SUBSTANTIALLY THE SAME SIZE WHEREBY SAID ELEMENTS MAY BE READILY URGED TOWARDS EACH OTHER TO FORM A SEAL WITH THE INNER SURFACE OF THE SHOTSHELL AND TO PRODUCE A CUSHIONING EFFECT THEREAT WHEN THE BASE WAD IS SUBJECTED TO PRESSURE FORCES PRODUCED BY A DETONATED PROPELLER CHARGE.