Reduced friction projectile

• US 7,900,561 B2
• Filed: 05/21/2010
• Issued: 03/08/2011
• Est. Priority Date: 10/21/2005
• Status: Expired due to Fees

• Current Assignee: Liberty Opco, LLC
• Original Assignee: Liberty Ammunition LLC
• Inventors: Marx, PJ
• Primary Examiner(s): Bergin; James S
• Application Number:
  US12/784,659
• Publication Number:
  US 20100224095A1
• Time in Patent Office: 291 Days
• Field of Search: 102/501, 102/503, 102/516, 102/517, 102/524, 102/525, 102/526
• US Class Current: 102/526
• CPC Class Codes: F42B 14/02 Driving bands; Rotating bands F42B14/04 takes precedence

Abstract

A projectile includes a leading part formed by a tip, a tip base, and a leading rod. A trailing part includes a main base, a truncate base, and a trailing rod. A leading end of a cylindrical interface abuts an annular shoulder where the tip meets the tip base and a trailing end abuts an annular shoulder where the main base meets the truncate base. The tip base and the truncate base respectively support the leading and trailing ends of the cylindrical interface. A medial extent of the cylindrical interface is unsupported by the leading and trailing rods and is deformed radially inwardly by lands in a barrel when the projectile is fired. The leading and trailing ends of the cylindrical interface maintain contact with the lands and the medial extent does not, reducing friction between the projectile and the barrel without sacrificing spin of the projectile.

Claims

1. A projectile, comprising:

a leading part formed by a tip having a generally ogive shape;

a tip base of cylindrical construction having a reduced diameter relative to a trailing end of said tip so that a first annular shoulder is formed where said trailing end of said tip meets a leading end of said tip base;

a leading rod formed integrally with said tip base and having a reduced diameter relative to said tip base so that a second annular shoulder is formed where a trailing end of said tip base meets a leading end of said leading rod;

a trailing part formed by a main base;

a truncate base of cylindrical construction formed integrally with a leading end of said main base and having a reduced diameter relative to said leading end of said main base so that a third annular shoulder is formed where said leading end of main base meets said trailing end of said truncate base;

a trailing rod formed integrally with a leading end of said truncate base and having a reduced diameter relative to said truncate base so that a fourth annular shoulder is formed where said leading end of said truncate base meets said trailing end of said trailing rod;

a cylindrical interface including a leading end that abuttingly engages said first annular shoulder and a trailing end that abuttingly engages said third annular shoulder;

said leading end of said cylindrical interface supported by said tip base and said trailing end of said cylindrical interface supported by said truncate base;

a medial extent of said cylindrical interface between said leading end and said trailing end being unsupported by said leading rod and said trailing rod;

said medial extent being deformed radially inwardly by lands in a barrel when said projectile is fired from said barrel;

whereby the leading and trailing ends of said cylindrical interface maintain contact with said lands and said medial extent does not, thereby reducing friction between said projectile and said barrel without sacrificing spin of said projectile.

2. The projectile of claim 1, further comprising:

said leading rod having a flat trailing end that abuts a flat leading end of said trailing rod when the leading end of said cylindrical interface abuts said first annular shoulder and the trailing end of said cylindrical interface abuts said third annular shoulder.

3. The projectile of claim 2, further comprising:

said leading rod and said trailing rod having a cylindrical configuration so that said cylindrical interface conforms to such cylindrical configuration along said medial extent thereof when said medial extent is deformed by said lands.

4. The projectile of claim 2, further comprising:

a first plurality of radially outwardly projecting elongate ribs formed in said leading rod in equidistantly and circumferentially spaced apart relation to one another and in parallel relation to a longitudinal axis of symmetry of said projectile;

a second plurality of radially outwardly projecting elongate ribs formed in said trailing rod in equidistantly and circumferentially spaced apart relation to one another and in parallel relation to a longitudinal axis of symmetry of said projectile;

said first and second plurality of elongate ribs disposed in supporting relation to said cylindrical interface so that when the lands supply radially inwardly directed forces, only circumferentially spaced apart elongate parts of said cylindrical interface between said first and second plurality of elongate ribs are unsupported and therefore deformed in a radially inward direction.

5. The projectile of claim 2, further comprising:

said leading rod and said trailing rod having a hexagonal cross-sectional configuration so that said medial extent of said cylindrical interface conforms to said hexagonal shape when said medial extent is deformed by said lands.

6. The projectile of claim 2, further comprising:

said leading rod and said trailing rod having a cross-sectional configuration of predetermined geometric configuration so that said medial extent of said cylindrical interface conforms to said predetermined geometric configuration when said medial extent is deformed by said lands.