# US 7,607,392 B2 · Shellcase for controlling reflections of primer shockwaves > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,392 B2 - Document ID: US7607392B2 - Status: Granted - Kind: B2 - Application number: 10/980,107 - Filed: 2004-11-01 - Published: 2006-05-04 - Granted: 2009-10-27 - Earliest claimed: 2004-11-01 - Assignees: Olin Corporation - Inventors: Michael Eugene Stock, Jr. - Web page: https://patentgrep.com/patent/US7607392B2 ## CPC - F42B 5/025: {characterised by the dimension of the case or the missile} - F42B 5/26: Cartridge cases (F42B5/18 takes precedence {; manufacturing of cartridge cases B21K21/04}) - F42B: EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION (explosive compositions C06B; fuzes F42C; blasting F42D) ## Abstract A shellcase body for use as part of an ammunition cartridge, which includes a base portion at one end, a middle portion having a substantially straight sidewall and joined with the base portion, and a shoulder portion joined to and extending from the middle portion. A neck portion may be joined to and extend from the shoulder portion. The shoulder portion is typically annularly shaped and includes a semi-circular sidewall that extends between an aft end and a fore end. The semi-circular sidewall has a curvature that is defined by a circular arc having a predetermined radius and a center that is positioned a distance away from the shellcase body center longitudinal axis. The shoulder portion is joined with the straight sidewall at a secant point of the circular arc, i.e., the straight sidewall defines a secant line that intersects the circular arc at the aforementioned secant point. ## Claims ### Claim 1 A shellcase body for use as part of an ammunition cartridge, comprising: a base portion having proximate thereto a point of origin from which primer explosion is initiated; a middle portion joined with said base portion, said base portion and said middle portion being arranged around a center longitudinal axis; a shoulder portion having a curvature that is defined by a circle having a predetermined radius and a center that is positioned a distance away from said center longitudinal axis, wherein said shoulder portion is joined with said middle portion at a secant point of said circle and extends therefrom to form an open end, said radius and center defining an interior surface having an angular orientation relative to said point of origin that is effective for redirecting substantially all shock waves originating from said point of origin away from said open end of said shoulder, to thereby reduce the risk of a projectile associated with said open end from becoming prematurely dislodged as a result of shockwaves. ### Claim 2 (depends on 1) A body according to claim 1, further comprising a neck portion joined with said shoulder portion at an end opposite said secant point. ### Claim 3 (depends on 2) A body according to claim 2, wherein said neck portion is sized to encircle a projectile having a predetermined caliber. ### Claim 4 (depends on 1) A body according to claim 1, wherein said base portion further comprises a center boring, said middle portion includes an internal cavity, and said center boring is in communication with said internal cavity. ### Claim 5 (depends on 4) A body according to claim 4, further comprising a means for reducing a ratio of a surface area of said internal cavity to a volume of said internal cavity. ### Claim 6 (depends on 4) A body according to claim 4, wherein said center boring is sized to hold a primer of predetermined size. ### Claim 7 (depends on 4) A body according to claim 4, wherein said internal cavity is sized to hold a predetermined amount of a propellant. ### Claim 8 (depends on 1) A body according to claim 1, wherein said middle portion includes a tapered sidewall defined by a circular arc. ### Claim 9 (depends on 1) A body according to claim 1, wherein said base portion further comprises an annular groove, said middle portion further comprises an internal cavity, and said annular groove is in communication with said internal cavity. ### Claim 10 (depends on 1) The shellcase body of claim 1, wherein the shoulder portion and the middle portion joined at said secant point form a non-tangent junction, which junction has a degree of secancy between the inner surfaces of the shoulder portion and middle portion that is effective for reflecting a substantial portion of all shock waves in a direction other than through the open end of the shoulder portion. ### Claim 11 (depends on 1) The shellcase body of claim 1, wherein the shoulder portion is tuned by varying the degree of non-tangency of the junction between the shoulder semi-circular and straight side walls of the middle portion to concentrate a greater portion of the redirected explosion shockwaves away from the direction of the open end of the shoulder portion. ### Claim 12 A shellcase body for use as part of an ammunition cartridge, comprising: an annular base portion having a center boring formed therethrough, having proximate thereto a point of origin from which primer explosion is initiated; a substantially cylindrical middle portion having a substantially straight sidewall including an aft end and a fore end, said aft end being joined with said annular base portion, said annular base portion and said substantially cylindrical middle portion being arranged around a center longitudinal axis; an annular shoulder portion having a semi-circular sidewall that extends between an aft end and a fore end, said semi-circular sidewall having a curvature that is defined by a circle having a predetermined radius and a center that is positioned a distance away from said center longitudinal axis, wherein said aft end is joined with said fore end of said substantially straight sidewall at a secant point of said circle; and a substantially cylindrical neck portion having a substantially straight sidewall including an aft end and a fore end, said aft end being joined with said fore end of said semi-circular sidewall, wherein said predetermined radius and center of said annular shoulder portion define an interior surface having an angular orientation relative to said point of origin that is effective for redirecting a substantial portion of all shock waves originating from said point of origin away from entry into said substantially cylindrical neck portion, to thereby reduce the risk of a projectile associated with said open end from becoming prematurely dislodged as a result of shockwaves. ### Claim 13 (depends on 12) A body according to claim 12, wherein said substantially cylindrical middle portion further comprises an internal cavity that is in communication with said center boring. ### Claim 14 (depends on 13) A body according to claim 13, further comprising a means for reducing a ratio of a surface area of said internal cavity to a volume of said internal cavity. ### Claim 15 (depends on 13) A body according to claim 13, wherein said center boring is sized to hold a primer of predetermined size. ### Claim 16 (depends on 15) A body according to claim 15, wherein said internal cavity is sized to hold a predetermined amount of a propellant. ### Claim 17 (depends on 12) A body according to claim 12, wherein said substantially cylindrical neck portion is sized to encircle a projectile having a predetermined caliber. ### Claim 18 (depends on 12) A body according to claim 12, wherein said substantially straight sidewall is tapered and defined by a circular arc. ### Claim 19 (depends on 12) The shellcase body of claim 12, wherein the annular shoulder portion and the substantially cylindrical middle portion joined at said secant point form a non-tangent junction, which junction has a degree of secancy between the inner surfaces of the annular shoulder portion and middle portion that is effective for reflecting a substantial portion of all shock waves in a direction other than through the substantially cylindrical neck portion. ### Claim 20 (depends on 12) The shellcase body of claim 12, wherein the annular shoulder portion is tuned by varying the degree of non-tangency of the junction between the shoulder semi-circular and straight side walls of the middle portion to concentrate a greater portion of the redirected explosion shockwaves away from the direction other than through the substantially cylindrical neck portion. ### Claim 21 An ammunition cartridge, comprising: a shellcase body including: an annular base portion having a center boring formed therethrough, having proximate thereto a point of origin from which primer explosion is initiated; a substantially cylindrical middle portion having a substantially straight sidewall including an aft end and a fore end, said aft end being joined with said annular base portion, said annular base portion and said substantially cylindrical middle portion being arranged around a center longitudinal axis, said substantially cylindrical middle portion having an internal cavity in communication with said annular base portion; an annular shoulder portion having a semi-circular sidewall that extends between an aft end and a fore end, said semi-circular sidewall having a curvature that is defined by a circle having a predetermined radius and a center that is positioned a distance away from said center longitudinal axis, wherein said aft end is joined with said fore end of said substantially straight sidewall at a secant point of said circle; and a substantially cylindrical neck portion having a substantially straight sidewall including an aft end and a fore end, said aft end being joined with said fore end of said semi-circular sidewall; a primer positioned within said center boring of said annular base portion; a propellant positioned within said internal cavity of said substantially cylindrical middle portion; and a projectile having fore and aft portions, at least a portion of said projectile positioned in and retained by said substantially cylindrical neck portion, said aft portion positioned adjacent said aft end of said substantially cylindrical neck portion and said fore portion extending from said substantially cylindrical neck portion, wherein said predetermined radius and center of said annular shoulder portion define an interior surface having an angular orientation relative to said point of origin that is effective for redirecting a substantial portion of all shock waves originating from said point of origin away from entry into said substantially cylindrical neck portion, to thereby reduce the risk of said projectile becoming prematurely dislodged as a result of shockwaves entering said cylindrical neck portion. ### Claim 22 (depends on 21) A cartridge according to claim 21, wherein said predetermined radius is selected so as to direct shockwaves from an explosion of said primer to an area within said substantially cylindrical middle portion and adjacent to said aft portion of said projectile. ### Claim 23 (depends on 21) A cartridge according to claim 21, further comprising means for directing shockwaves from an explosion of said primer to an area within said substantially cylindrical middle portion and adjacent to said aft portion of said projectile.