A caseless ammunition cartridge includes a unitary outer portion having forward, central section and rear sections. The forward section has an aerodynamic tangent ogive profile. The rear section has a cylindrical profile. The central section has a conical profile that transitions from the radius of the forward section to the radius of the rear section. An inner core, disposed within the unitary metallic outer portion, has a front portion encased by the forward section of the unitary outer portion, and a cylindrical rear portion disposed within the central and rear sections of the unitary outer portion. An annular cavity is disposed between the unitary outer portion and the rear portion of the inner core. A propellant is disposed within the annular cavity. A combustible seal covers the annular cavity to protect the propellant.

A smooth-bore barrel assembly including a first segment that extends downstream of a powder chamber, a bore followed by a segment having an increased diameter, and a final choke constituted by a first final portion and by a second final portion; the barrel is characterized in that the first segment has a divergent-convergent configuration, constituted by a divergent portion and by a convergent portion, or a solely convergent or solely divergent configuration. Advantageously, the barrel assembly can be provided in a modular form and includes three basic components: a barrel body, an extension, an inner choke member and/or an outer choke member.

A smooth-bore barrel assembly including a first segment that extends downstream of a powder chamber, a bore followed by a segment having an increased diameter, and a final choke constituted by a first final portion and by a second final portion; the barrel is characterized in that the first segment has a divergent-convergent configuration, constituted by a divergent portion and by a convergent portion, or a solely convergent or solely divergent configuration. Advantageously, the barrel assembly can be provided in a modular form and includes three basic components: a barrel body, an extension, an inner choke member and/or an outer choke member.

A gun-type firing device using a caseless projectile is disclosed. The caseless projectile has a bullet head and an impact seat at two ends thereof and a groove adjacent to the impact seat. The gun-type firing device includes a gunstock, a gun bolt and a gun barrel. The gun bolt is located on one side of the gunstock. The gun bolt includes a cocking handle and an extractor. The cocking handle can perform a linear displacement movement along the extension direction of the gunstock. The extractor is located at one end of the cocking handle. The gun barrel is located on the gunstock and is adjacent to one end of the gun bolt. The gun barrel does not have rifling.

A gun-type firing device using a caseless projectile is disclosed. The caseless projectile has a bullet head and an impact seat at two ends thereof and a groove adjacent to the impact seat. The gun-type firing device includes a gunstock, a gun bolt and a gun barrel. The gun bolt is located on one side of the gunstock. The gun bolt includes a cocking handle and an extractor. The cocking handle can perform a linear displacement movement along the extension direction of the gunstock. The extractor is located at one end of the cocking handle. The gun barrel is located on the gunstock and is adjacent to one end of the gun bolt. The gun barrel does not have rifling.

A specialized underwater pistol with ammunition includes one or more of barrel expansions to shape the pattern of the plural shot pieces expelled from a pistol cartridge when the pistol is fired, an aerodynamic trigger cam or spur, flushing ports, a wide trigger pull, a wide hammer spur, a cartridge shot carrier with a frangible end, and cartridge sealant.

A specialized underwater pistol with ammunition includes one or more of barrel expansions to shape the pattern of the plural shot pieces expelled from a pistol cartridge when the pistol is fired, an aerodynamic trigger cam or spur, flushing ports, a wide trigger pull, a wide hammer spur, a cartridge shot carrier with a frangible end, and cartridge sealant.

A flechette for use with a gun barrel having a tapered bore with a diameter at the initial bore section greater than the diameter at the emergent bore. The flechette includes a body constructed of a ductile material and having an elongated axis aligned with the axis of the tapered bore when positioned in the load end of the bore. The body also includes a cylindrical bulkhead as well as a bourrelet that are axially spaced from each other along the flechette and have an outside diameter substantially the same as the diameter at the initial bore section of the tapered bore. An elongated boom is attached at the tail end of the body while a penetrator is attached at the forward end of the body. Upon launch, both the bulkhead and bourrelet are compressed radially inward by the bore reduction so that the body is substantially cylindrical upon exit from the discharge end of the bore.

A projectile launching system can include a projectile launcher and a projectile. The projectile launcher can include at least one barrel, a projectile, a firing pin mechanism, an activator, and a power system. The barrel can extend along a longitudinal axis between first and second ends, with an exit port at the second end. The projectile can be positioned in the barrel and include primer, propellant, and a sub-projectile. The firing pin mechanism can be selectively project into the barrel to engage the primer, whereby the propellant is ignited and the projectile is launched out of the barrel. The activator can be engaged with the firing pin mechanism and engageable by a user to control the firing pin mechanism. The power system can rotate the barrel or the projectile as the firing pin mechanism is projecting into the barrel and engaging the primer of the projectile.

A gun barrel that has a proximal chamber end, a distal muzzle end, and an internal bore bounded by a bore wall, the internal bore having a first rifled bore section proximate to the proximal chamber end of the barrel, a second rifled bore section at the distal muzzle end of the barrel, and a reducing section distal to the first rifled bore section and connecting the first rifled bore section and the second rifled bore section, wherein at least one of the first rifled bore section and the second rifled bore section have straight groove rifling.