Abstract: The lower wall of the pre-formed jacket of a bullet is thicker than the upper portion of the jacket and the uppermost or open end of the pre-formed jacket is deformed on its interior surface to provide a plurality of flat surfaces which are joined by a plurality of axial grooves. An inwardly-extending annular ring having a downwardly sloping upper surface and an upwardly sloping undersurface is formed at a shoulder by compression between the lower, thicker wall and the thinner wall adjoining it and, where the core is pressed into the jacket, the annular ring is deformed so that its undersurface becomes perpendicular to the wall of the jacket, thus engaging and holding the base of the core within the jacket. The core and jacket are subsequently deformed into a conventional dynamic shape.

Abstract: The lower wall of the pre-formed jacket of a bullet is thicker than the upper portion of the jacket and the uppermost or open end of the pre-formed jacket is deformed on its interior surface to provide a plurality of flat surfaces which are joined by a plurality of axial grooves. An inwardly-extending annular ring having a downwardly sloping upper surface and an upwardly sloping undersurface is formed at a shoulder by compression between the lower, thicker wall and the thinner wall adjoining it and, where the core is pressed into the jacket, the annular ring is deformed so that its undersurface becomes perpendicular to the wall of the jacket, thus engaging and holding the base of the core within the jacket. The core and jacket are subsequently deformed into a conventional dynamic shape.