Lead-Free Expansion Projectile and Manufacturing Process

• US 20080314280A1
• Filed: 03/17/2005
• Published: 12/25/2008
• Est. Priority Date: 03/17/2005
• Status: Abandoned Application

• Current Assignee: Cbc Companhia Brasileira De Cartuchos
• Original Assignee: Cbc Companhia Brasileira De Cartuchos
• Inventors: Martini Filho, Laudemiro
• Application Number:
  US11/908,958
• Publication Number:
  US 20080314280A1
• Time in Patent Office: Days
• US Class Current: 102/510
• CPC Class Codes: F42B 12/34 expanding before or on impact, i.e. of dumdum or mushroom type

Abstract

The projectile of the present invention combines the advantages of both the solid and hollow point designs, featuring the initial ballistics of a solid projectile and the terminal (target) ballistic effects of a hollow-point projectile, without the risk of collecting undesired foreign matter into the cavity in the unfired configuration and also eliminating the possible feeding problems from the magazine to the barrel chamber by a simple manufacturing process. A plunger (4) is initially positioned in the expansion chamber (2) of the projectile. Upon sinking into the projectile body (1) no part of the plunger head (5) touches the internal surface of the expansion chamber (2) except for the bottom of such chamber (2) so that the plunger (4) has no active role in the expansion of the projectile upon impact.

Claims

1. An expansion projectile for firearms, comprising:

(a) a first piece having a deformable, cylindrical projectile body (1) with a front part tapering towards a front end, a set of regularly spaced slits placed at the front end of the projectile and an internal cavity opened towards said front end, composed of an expansion chamber (2) connected to a cylindrical haft extension (3) and

(b) a second piece having a plunger (4) with the general shape of a nail with a head (5) and a shank (6), with all elements featuring radial symmetry around the longitudinal axis of the projectile, wherein the plunger (4) is initially positioned so that the external face of the head (5) lies exposed at the very front tip of the projectile and the shank (6) lies inserted into the expansion chamber (2), wherein upon sinking into the projectile body (1), no part of the plunger (4) head (5) touches the internal surface of the expansion chamber (2) except for the bottom of said chamber at the end of the course of the sinking movement.

2. An expansion projectile for firearms, according to claim 1, wherein the full axial length of the plunger (4) is such that, in the unfired configuration, a length preferably between 5 and 25% of the plunger total extension lies inserted into the forward portion of the shaft (3).

3. An expansion projectile for firearms, according to claim 1, in which the external shape of the head (5) of the plunger (4) is such that the projectile presents an uninterrupted aerodynamic profile in its unfired configuration which is preserved after firing until the moment of impact, characterized by the fact that the cross-section of the shank (6) of the plunger (4) is preferably that of a regular polyhedron with 3 to 8 sides, featuring axial symmetry regarding the longitudinal axis of the projectile, with contact between the pieces occurring at the tips of the polyhedral figure, thus leaving a certain amount of free section between the hank (6) and the cylindrical shaft (3).

4. An expansion projectile for firearms, according to claim 2, wherein the external shape of the head (5) of the plunger (4) is such that the projectile presents an uninterrupted aerodynamic profile in its unfired configuration which is preserved after firing until the moment of impact, characterized by the fact that the cross-section of the shank (6) of the plunger (4) is preferably that of a regular polyhedron with 3 to 8 sides, featuring axial symmetry regarding the longitudinal axis of the projectile, with contact between the pieces occurring at the tips of the polyhedral figure, thus leaving a certain amount of free section between the hank (6) and the cylindrical shaft (3).

5. An expansion projectile for firearms, according to claim 1, wherein the projectile presents a cavity opened towards the front end after the plunger (4) sinks into the projectile upon impact, characterized by the fact that the maximum cross section radius of the shank (6) is slightly bigger than the nominal cross-section radius of the cylindrical shaft (3), with the penetration of the shank (6) into the shaft (3) being allowed by deformation of the material of the plunger (4) under the force of the projectile impact.

6. An expansion projectile for firearms, according to claim 1, wherein there are no regularly spaced slits placed at the front end of the projectile.

7. An expansion projectile for firearms, according to claim 1, wherein the mass of the plunger (4) is no more than 5% of the total mass of the projectile in its unfired configuration.

8. A manufacturing process for the projectile according to claim 1, comprising:

(a) forming of the cylindrical shaft extension (3) placed right behind the expansion chamber (2) and continuously connected to it;

(b) calibrating against a perfectly symmetrical model.