Abstract: A casing for use in a cartridge for a firearm comprises a sleeve portion and a base portion, where the base has cannelure comprised of curving surfaces. In a casing embodiment, a sleeve has cylindrical portion with a mouth for holding a bullet and an opposing end radially-running bulkhead. A nipple extends from the bulkhead and into a passageway of the base, thereby securing the sleeve to the base. The sleeve bulkhead preferably has at least one circumferential wave and contacts a distal end surface of the base, which may be planar or conical. The cannelure is characterized by a continuously curving groove bottom, a maximum groove depth diameter that is 60 to 80 percent of the base outside diameter, and a volume that is 20 to 43 percent of the volume of a like base which has no cannelure.

Abstract: A cartridge for a firearm comprises a casing which comprises a sleeve that is mated with a base. Propellant and a bullet are contained within concavity of the sleeve. The sleeve comprises a nipple extending from a bulkhead. The nipple is flared within a passageway of the base, to hold the base and sleeve together. The base comprises a base substrate and shroud. The shroud is a ring like element around the end of the base which abuts the bulkhead of the sleeve. The shroud may provide structural strength and may be colored, textured or marked; or may hold a RFID tag.

Abstract: A casing for use in a cartridge for a firearm comprises a sleeve and attached base. The sleeve has cylindrical portion with a mouth for holding a bullet and an opposing radially-running bulkhead from which extends a nipple that is secured within a passageway of the base by a lip at the nipple terminal end. There are one or more seal regions in the passageway. A sleeve is preferably made of austenitic stainless steel and there are differing hardness and magnetic properties along the sleeve length. Particularly for high pressure rounds, the bulkhead has a frusto-conical portion with one or more circumferential waves and mates with a conical depression in the surface of the base; optionally, a skirt around the periphery of the base provides support to the sleeve bulkhead. A base has a deep cannelure with a continuously curving groove bottom, enabling a base to be made of an iron alloy into which carbon is diffused to enable hardening, after machining.

Abstract: A casing for use in a cartridge for a firearm comprises a sleeve and attached base. The sleeve has cylindrical portion with a mouth for holding a bullet and an opposing radially-running bulkhead from which extends a nipple that is secured within a passageway of the base by a lip at the nipple terminal end. There are one or more seal regions in the passageway. A sleeve is preferably made of austenitic stainless steel and there are differing hardness and magnetic properties along the sleeve length. Particularly for high pressure rounds, the bulkhead has a frusto-conical portion with one or more circumferential waves and mates with a conical depression in the surface of the base; optionally, a skirt around the periphery of the base provides support to the sleeve bulkhead. A base has a deep cannelure with a continuously curving groove bottom, enabling a base to be made of an iron alloy into which carbon is diffused to enable hardening, after machining.

Abstract: A device for reshaping casings of spent ammunition cartridges, in one embodiment reduces the diametrical size of the casing wall by forcing the casing into an annular space at the end of a housing through which a plunger shaft slides. In another embodiment, the mouth of a casing is flared outwardly by engagement with the exterior of the end of a housing which has a circumscribing groove to enable easier disengagement of the re-shaped casing. The preferred reshaping devices comprise a plunger having shaft which, when contacted by a casing being re-shaped, compresses an elastomer spring that substantially fills a spring housing cavity and has an exceptionally high spring rate. After each reshaping, the spring causes the plunger shaft to disengage the casing from the device. A recess in the terminal end of a plunger shaft avoids damaging new types of unique two piece casings that have a wave at the interior bottom of the casing.

Abstract: A casing for use in a cartridge for a firearm comprises a sleeve and attached base. The sleeve has cylindrical portion with a mouth for holding a bullet and an opposing bulkhead from which extends a nipple. At the terminal end of the nipple is a lip that radially decreases in thickness and has curved surface portions; the lip forms a first seal region within a passageway that runs through the base. Preferably a second seal zone around the nipple near the bulkhead. A bulkhead comprises a circumferential wave or ridge that creates a hollow on the surface facing the base. A sleeve is preferably made of austenitic stainless steel that has differential hardness and magnetic properties along the sleeve length; and the base has a hardness less than any portion of the sleeve.

Abstract: A casing for use in a cartridge for a firearm comprises a sleeve and attached base. The sleeve is formed with a mouth for holding a bullet and an opposing bulkhead from which extends a nipple. The end of the nipple is flared radially outwardly within a passageway of the base, to form a special configuration lip and first seal. The nipple is shaped to make a second seal when press fitted into the passageway. A bulkhead is formed with a circumferential wave or ridge. A sleeve is preferably made from austenitic stainless steel that is worked to have differential hardness and magnetic properties along the sleeve length, with the nipple being of lesser hardness.

Abstract: A casing for use in a cartridge for a firearm comprises a sleeve and attached base. The sleeve has cylindrical portion with a mouth for holding a bullet and an opposing bulkhead from which extends a nipple. At the terminal end of the nipple is a lip that radially decreases in thickness and has curved surface portions; the lip forms a first seal region within a passageway that runs through the base. Preferably a second seal zone around the nipple near the bulkhead. A bulkhead comprises a circumferential wave or ridge that creates a hollow on the surface facing the base. A sleeve is preferably made of austenitic stainless steel that has differential hardness and magnetic properties along the sleeve length; and the base has a hardness less than any portion of the sleeve.

Abstract: A casing for use in a cartridge for a firearm comprises a sleeve and attached base. The sleeve is formed with a mouth for holding a bullet and an opposing bulkhead from which extends a nipple. The end of the nipple is flared radially outwardly within a passageway of the base, to form a special configuration lip and first seal. The nipple is shaped to make a second seal when press fitted into the passageway. A bulkhead is formed with a circumferential wave or ridge. A sleeve is preferably made from austenitic stainless steel that is worked to have differential hardness and magnetic properties along the sleeve length, with the nipple being of lesser hardness.