US 5,708,231 AGranted

Delayed release cartridge for a firearm

AssigneeSigma Research, Inc.

InventorHomer Koon

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Abstract

A cartridge is disclosed for use in a ballistic weapon system. The cartridge includes a tubular case and a ballistic projectile. The projectile has an annular groove which extends into an exterior periphery of the projectile. The tubular case has a cylindrical sidewall and a substantially closed rearward end. The cylindrical sidewall defines an interior cavity for receiving at least a rearward portion of the projectile. An annular lug is integrally formed with the cylindrical sidewall and inwardly extends from the sidewall into the annular groove of the projectile, interlocking the projectile and the tubular case. Longitudinal slits are formed in the forward end of the tubular case to allow the case to expand for receipt of the projectile until the annular lug is aligned with and then inserted into the annular groove of the projectile. After the cartridge is fired, the annular lug restrains the projectile within the tubular cartridge case until combustion of the charge causes a rapid pressure buildup to exceed a predetermined pressure, which causes the predetermined shear strength of the annular lug to be exceeded. The annular lug then shears and the projectile moves forward from within the tubular case.

Claims14

Dependent claims

A cartridge for use in a ballistic weapon system, comprising:

a projectile having an exterior periphery and two annular recesses which are spaced apart and formed into said exterior periphery;
a tubular case having a one-piece plastic body which includes an interior cavity defined by at least one sidewall and a substantially enclosed rearward end;
said one piece plastic body including two annular retaining members which inwardly extend from said sidewall of said tubular case into said recesses of said projectile, interlocking said projectile and said tubular case;
wherein said projectile extends into said interior cavity of said tubular case, such that said recesses formed into said exterior periphery of said projectile are aligned with corresponding ones of said retaining members and said retaining members extend into respective ones of said recesses to interlock said projectile to said tubular case;
said sidewall of said tubular case including at least one slot which extends rearward from a forward end of said tubular case and rearward of said two retaining members for allowing said forward end of said tubular case to expand and receive said projectile, and then to return to a closed position such that said retaining members extend into said recesses to interlock said projectile to said tubular case;
and
said retaining members together having a predetermined shear strength for interlocking said projectile within said tubular case until said shear strength is exceeded and said retaining member is sheared in response to a predetermined pressure buildup within said tubular case when said cartridge is fired.

4 more elements

A cartridge for use in a ballistic weapons system, comprising:

a projectile having a cylindrical body with two annular grooves formed transversely into an exterior periphery thereof, spaced apart in a longitudinal direction;
a tubular case having a one-piece plastic body, wherein said one-piece plastic body includes a cylindrical sidewall and a substantially enclosed rearward end which define an interior cavity for receiving at least a rearward portion of said projectile;
said rearward portion of said projectile being disposed within said interior cavity of said tubular case;
said one-piece plastic body of said tubular case further including two annular lugs which are spaced apart from one another and inwardly extend from said cylindrical sidewall for aligning with and fitting within respective ones of said grooves of said projectile, interlocking said projectile and said tubular case;
and
wherein a plurality of slots extend longitudinally into said cylindrical sidewall of said tubular case, each of said slots extending longitudinally forward of and rearward of said annular lugs, and each of said slots extending to a forward end of said tubular case;
and
said annular lugs together having a predetermined shear strength in a direction of right of said projectile for interlocking said projectile and said tubular case until said shear strength of said annular lugs is exceeded by buildup of a preselected pressure within said interior cavity of said tubular case and said annular lugs are sheared when said cartridge is fired.

5 more elements

A cartridge for use in a ballistic weapons system, comprising:

a projectile having a cylindrical body with two annular grooves formed transversely into an exterior periphery thereof, spaced apart in a longitudinal direction, said grooves being continuous and circumferentially extending transversely into said periphery of said cylindrical body;
a tubular case having a one-piece plastic body, wherein said one-piece plastic body includes a cylindrical sidewall and a substantially enclosed rearward end which define an interior cavity for receiving at least a rearward portion of said projectile;
said rearward portion of said projectile being disposed within said interior cavity of said tubular case;
said one-piece plastic body of said tubular case further including two annular lugs which are spaced apart from one another and inwardly extend from said cylindrical sidewall for aligning with and fitting within respective ones of said grooves of said projectile, interlocking said projectile and said tubular case;
one of said annular lugs having a triangular shaped cross-section and the other of said annular lugs having a generally rectangular shaped cross-section with tapered edges for engaging within respective ones of said grooves formed into said exterior periphery of said projectile;
wherein a plurality of slots extend longitudinally into said cylindrical sidewall of said tubular case, each of said slots extending longitudinally forward of and rearward of said annular lugs, segmenting each of said annular lugs, and each of said slots extending to a forward end of said casing;
said annular lugs together having a predetermined shear strength in a direction of flight of said projectile defined by respective thicknesses of said annular lugs in said direction of flight;
and
said annular lugs being received within respective ones of said grooves, interlocking said projectile and said tubular case until said shear strength of said annular lugs is exceeded by buildup of a preselected pressure within said interior cavity of said tubular case and said annular lugs are sheared when said cartridge is fired.

6 more elements

Dependencies are inferred from the claim text.