In various embodiments, a projectile includes a projectile body including a tail portion, a nose portion, a barrel engaging portion between the nose portion and the tail portion, and a metal jacket that defines an exterior of the projectile that surrounds an interior solid core. In one or more embodiments the projectile includes one or more circumferential grooves defined in the interior core portion, each of the one or more circumferential grooves covered by and positioned adjacent to the metal jacket and within the barrel-engaging portion. In various embodiments, during firing of the projectile, the one or more circumferential grooves define a void that allows material of one or more of the metal jacket and interior solid core to displace into the void for reduction in radial stiffness to the projectile in the barrel engaging portion.

In various embodiments, a projectile includes a projectile body including a tail portion, a nose portion, a barrel engaging portion between the nose portion and the tail portion, and a metal jacket that defines an exterior of the projectile that surrounds an interior solid core. In one or more embodiments the projectile includes one or more circumferential grooves defined in the interior core portion, each of the one or more circumferential grooves covered by and positioned adjacent to the metal jacket and within the barrel-engaging portion. In various embodiments, during firing of the projectile, the one or more circumferential grooves define a void that allows material of one or more of the metal jacket and interior solid core to displace into the void for reduction in radial stiffness to the projectile in the barrel engaging portion.

A cartridge with a bullet has desirable penetration capabilities and controlled separation of components upon terminal impact. In embodiments of the invention, the bullet comprises a forward component, a lead core, and a copper jacket. The bullet having a forward nose portion with a plurality of cutaways spaced circumferentially about the nose portion. The copper jacket having a leading edge portion positioned at the cutaways.

A sub-mass projectile for a standard, unmodified firearm, comprising a core formed from a malleable core material with at least a portion of the core material being a non-metal material. The core has a lower mass than a standard projectile for the standard, unmodified firearm. An outer surface associated with the core has a diameter that is sized less than an outer diameter of a standard cartridge and larger than an inner diameter of a standard, unmodified barrel bore of the standard, unmodified firearm such that the outer surface associated with the core contacts the inner diameter of the standard, unmodified barrel bore to generate forces in the firearm that approximate operational forces of a standard mass projectile on the standard, unmodified firearm during operation.

A sub-mass projectile for a standard, unmodified firearm, comprising a core formed from a malleable core material with at least a portion of the core material being a non-metal material. The core has a lower mass than a standard projectile for the standard, unmodified firearm. An outer surface associated with the core has a diameter that is sized less than an outer diameter of a standard cartridge and larger than an inner diameter of a standard, unmodified barrel bore of the standard, unmodified firearm such that the outer surface associated with the core contacts the inner diameter of the standard, unmodified barrel bore to generate forces in the firearm that approximate operational forces of a standard mass projectile on the standard, unmodified firearm during operation.

The present invention relates to increasing the flight stability of a bullet in subsonic flight. The bullet may incorporate features that impart additional angular momentum during flight. Helical fins may be configured such that laminar airflow over the bullet during flight increases rotational forces, thus increasing the angular momentum of the bullet and stabilizing it during flight. The fins may be self-forming during the use of the bullet or may be formed during manufacturing.

The present invention relates to increasing the flight stability of a bullet in subsonic flight. The bullet may incorporate features that impart additional angular momentum during flight. Helical fins may be configured such that laminar airflow over the bullet during flight increases rotational forces, thus increasing the angular momentum of the bullet and stabilizing it during flight. The fins may be self-forming during the use of the bullet or may be formed during manufacturing.

A firearm with a cartridge has a barrel with an inside surface, a barrel length that is measured starting from a chamber to a barrel muzzle, and a barrel shaft, wherein the cartridge has a single, sabot-free projectile with a peripheral surface. A gap that is open end-to-end in the direction of the barrel shaft is present along at least 90% of the barrel length and over at least 90% of the circumference of the projectile between the peripheral surface of the projectile and the inside surface of the barrel.

The present invention discloses a bullet with a negative Poisson's ratio effect and a method of designing thereof. The bullet includes a cylindrical section of the bullet having a negative Poisson's ratio design, and a conical tail of the bullet and a tip of the bullet each with a matching design; the cylindrical section of the bullet is a tubular structure having periodically alternating transverse and vertical holes; the tubular structure includes a plurality of holes, with a center axis of one hole being axially perpendicular to a center axis of another adjacent hole, that is, the axis of each hole being structurally orthogonal to an adjacent hole; and the holes in rows and columns are periodically arranged into the tubular structure, which is a tubular structure having the negative Poisson's ratio effect.

A projectile system has a projectile with a metal body having a first outside diameter, a forward end and a rearward end, a plastic base wad engaged at the rearward end, the plastic base wad of solid plastic having a first length and a second outside diameter, greater than the first outside diameter, and a rifled barrel having a third inside diameter at the tips of the rifling, the third inside diameter greater than the first outside diameter but less than the second outside diameter, and a fourth diameter at the root of the rifling greater than the second outside diameter. With the projectile translating along the rifled barrel, the metal body passes inside the rifling, avoiding metal to metal friction, while the plastic base wad fully engages the rifling, imparting rotation to the metal projectile.