Base piece for a cartridge case for ammunition with a caliber of less than 20 mm

Abstract

A base piece for a cartridge case for ammunition with a caliber of less than 20 mm, in particular of less than 13 mm or less than 9 mm and more than 6 mm, in particular of 6.8 mm, characterized in that the material of the base piece is selected from the list containing structural steel having a carbon content of less than 0.15%, case-hardened steel having a carbon content of less than 0.25%, heat-treatable steel having a carbon content in the range from 0.2% to 0.65%, and a hardenable aluminum alloy.

Description

[0001] Base piece for a cartridge case for ammunition with a calibre of less than 20 mm.

[0002] The present invention relates to a base piece for receiving a primer cap for a single-piece or multi-piece cartridge case. Furthermore, the present invention relates to a method for producing a multi-piece cartridge case and a cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm.

[0003] Cartridge cases are generally known and can be constructed in one or more parts. Cartridge cases are generally divided into a base piece facing the primer cap and a shell for receiving a projectile. Cartridge cases of this type are known, for example, from DE 10 2021 124431 A1 and DE 102020 124 559 A1.

[0004] During the deep drawing of the case jacket, the greatest degree of deformation occurs in the area of ​​the open case mouth, which serves to receive the projectile. This is where the greatest hardening occurs. However, material hardening in this area is undesirable, particularly because it has a detrimental effect on the subsequent process step of inserting the projectile. Annealing processes are used to soften the material bonded there. This procedure is laborious and costly.

[0005] Furthermore, it was recognized that when the base piece and the sleeve are joined together, which is done according to the aforementioned prior art methods by pressing the base piece from the outside inward onto the sleeve, which is thus also compressed inward, both components spring back slightly outward due to the elasticity of the materials of the base piece and sleeve, which can lead to a reduction in the holding force between the base piece and sleeve. This can create a certain amount of play, which allows for relative rotation between the base piece and sleeve.

[0006] Finally, the inventors of the present invention discovered that, in both single-piece and multi-piece cartridge cases, the primer cap can be pushed out of the bore in the base during the firing of the ammunition. This loosening and possible detachment of the primer cap from the base can lead to malfunctions in the weapon.

[0007] An object of the present invention is to overcome the disadvantages of the prior art, in particular to provide a base piece in which the primer cap remains more reliably after the ammunition has been fired.

[0008] The problem is solved by the subject matter of the independent claims.

[0009] According to this, a base piece is provided for a cartridge case, in particular a multi-part cartridge case, for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, or less than 9 mm and more than 6 mm, in particular 6.8 mm. The base piece serves, among other things, to accommodate a primer cap.

[0010] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0011] According to one aspect of the present invention, the material of the base piece is selected from the list including structural steel with a carbon content of less than 0.15%, case-hardening steel with a carbon content of less than 0.25%, heat-treatable steel with a carbon content of 0.2% to 0.65%, and a heat-treatable aluminum alloy. It has been found that few materials are suitable for meeting the essentially complementary requirements of using the strongest possible material to withstand the high pressures during ammunition firing, while also exhibiting the best possible formability so that the base piece is both easy to manufacture and can be reliably joined to the case jacket. Cold forming processes such as deep drawing and / or pressing are generally used.The identified materials, especially those with the preferred carbon content in steel materials, have proven particularly advantageous with regard to the underlying objective of the present invention: preventing the primer cap from loosening. It has been found that materials with a carbon content of approximately 0% can be used at lower internal pressures.

[0012] According to an exemplary embodiment of the base piece according to the invention, the carbon content is in the range of 0.2% to 0.45%. These carbon contents apply particularly to heat-treated steel. It has been found that heat-treated steel with a carbon content above 0.45% is unsuitable for cold-forming the base pieces. Below 0.2% carbon content, the strength of the material is too low to withstand the high pressures during ammunition firing.

[0013] In a further exemplary embodiment of the base piece according to the invention, the material is selected and / or designed such that the yield strength of the base piece depends on the internal pressure, in particular is proportionally dependent, wherein the yield strength decreases in particular with lower internal pressure.

[0014] In a further exemplary embodiment of the base piece according to the invention, the base piece has a case jacket joining area for connecting to the case jacket and a receptacle for a primer cap facing away from the case jacket. The case jacket joining area is subjected to a heat treatment, in particular at a temperature exceeding the recrystallization temperature. Furthermore, the primer cap receptacle can be free of heat treatment.

[0015] For example, it may be necessary to carry out local temperature post-treatments in order to make a corresponding section of the joining partners more functional, in particular with regard to the respective requirements to be met by the joining partner. Thermal post-treatment of the primer cap holder has been identified as disadvantageous in that the primer cap may become loose within the primer cap holder when the ammunition is fired if the material of the primer cap holder is not sufficiently capable of reliably withstanding the high pressures during ammunition firing. According to an exemplary embodiment of the present invention, the base piece can be subjected to temperature treatment, in particular heat treatment, at least in sections, in particular completely. For example, the base piece is hardened to improve springback after firing.For example, the heat treatment can be carried out by vacuum hardening or case hardening, for example by adding plastic. The base piece can be hardened at least in sections, in particular completely, to a hardness of 400 HV10 to 600 HV10, in particular from 450 HV10 to 580 HV10 or in the range from 480 HV10 to 540 HV10. The specified hardness for the base piece has proven to be particularly suitable in view of the various requirements. A base piece with the specified hardness thus exhibits sufficiently good deformability, in particular for joining, and the higher hardness, namely strength, results in greater springback, which manifests itself in elastic expansion after firing. This can prevent the cartridge case from jamming in the firearm barrel.

[0016] According to a further exemplary embodiment of the present invention, the case jacket joining area has a lower hardness than the primer receptacle, in particular by less than 10%, less than 20%, or less than 30%. This allows the two functions of the base piece to be particularly effectively accommodated: first, the primer is reliably held in the primer receptacle without causing the primer to loosen, and second, the case jacket joining area is pretreated in such a way that the cold-forming joining with the case jacket can take place as effectively as possible.

[0017] In a further exemplary embodiment of the base piece according to the invention, the base piece further comprises a separating base that connects the primer receptacle and the case jacket joining area, which has a maximum hardness of the base piece. The separating base can be provided with an ignition bore so that the primer receptacle is fluidly connected to the case interior.

[0018] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a cartridge case, in particular a multi-part cartridge case, is provided for ammunition with a caliber of less than 20 mm, in particular less than 13 mm or less than 9 mm and more than 6 mm, in particular 6.8 mm.

[0019] The cartridge case according to the invention comprises a rotationally symmetrical case shell and a base piece, which is cold-formed thereto or manufactured in one piece therewith and is designed according to one of the preceding claims, for receiving a primer cap. The base piece can be designed according to one of the previously described aspects or exemplary embodiments.

[0020] With regard to the cold-forming fastening of the sleeve shell and base piece, reference is made to DE 10 2020 124 559 A1, the content of which is incorporated herein by reference.

[0021] The cold-forming joining of the base piece and sleeve shell can be achieved by cold-forming the base piece onto the sleeve shell, which elastically deforms the sleeve shell at least in sections as a result of the pressing. The base piece can be fastened to the sleeve shell by cold-forming in such a way that the sleeve shell is elastically and / or plastically deformed. As a consequence, the sleeve shell can exert an elastic deformation restoring force on the base piece resulting from the cold forming, in particular to reinforce a holding force or adhesion between the sleeve shell and base piece. This results in an elastic deformation restoring force oriented counter to the deformation movement, which prestresses the sleeve shell towards the base piece. This strengthens the attachment of the sleeve shell and base piece.

[0022] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a method is provided for producing a cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, in particular less than 9 mm and more than 6 mm, in particular 6.8 mm.

[0023] In the method according to the invention, a base piece formed according to one of the previously described aspects or exemplary embodiments and a case jacket for receiving a projectile are fastened to one another by cold forming with elastic and / or plastic deformation of at least the case jacket. Ammunition, also referred to as a cartridge, generally consists of the following components: a cartridge case, for example a multi-part one; a primer for igniting the propellant powder; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases generally comprise at least one base piece facing the primer or receiving the primer, and a case jacket manufactured separately and firmly connected to the base piece, which receives the projectile.

[0024] According to the method according to the invention, a base piece and a sleeve shell are fastened together by cold forming, with elastic and / or plastic deformation of at least the sleeve shell. Furthermore, the elastically deformed sleeve shell exerts an elastic deformation recovery force on the base piece resulting from the cold forming.

[0025] According to the invention, the sleeve shell exerts an elastic deformation restoring force on the base piece resulting from the cold forming process, in particular to reinforce the holding force or adhesion of the sleeve shell and base piece. The cold-forming joining of the base piece and sleeve shell can be achieved by cold-forming the base piece onto the sleeve shell, and as a result of the pressing, the sleeve shell is elastically and / or plastically deformed, at least in sections. This results in an elastic deformation restoring force oriented counter to the deformation movement, which prestresses the sleeve shell toward the base piece. This strengthens the attachment of the sleeve shell and base piece.

[0026] In an exemplary embodiment of the method according to the invention, the base piece is thermally post-processed, in particular by means of induction or laser, at a sleeve shell joining area for connection to the sleeve shell, in particular before or during joining. It has been found that the joining interface between the sleeve shell and the base piece can be pre-treated by means of thermal treatment before or during joining to improve the joining quality.

[0027] In a further exemplary embodiment of the method according to the invention, the method is designed to produce a cartridge case according to the invention. According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular less than 13 mm.

[0028] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0029] The case jacket according to the invention comprises a substantially cylindrical case section and a fastening section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0030] According to one aspect of the present invention, the fastening section is open at an end facing away from the sleeve section and is substantially hourglass-shaped. Alternatively or additionally, the fastening section has a support shoulder adjoining the sleeve section, in particular a conically tapered one, and an adjoining undercut leg, in particular a conically widening one. Because the sleeve shell is open on both sides, it can be formed during production to form the final desired shape with less effort than before. The combination of support shoulder and undercut leg allows the connection to the base piece to be achieved in a simple manner from a manufacturing perspective.The joining of the base piece and the sleeve shell can be carried out according to DE 10 20220 124 559 A1 in that the base piece is plastically deformed for connection to the fastening section of the sleeve shell and / or has bending wings designed according to the fastening section, which on the one hand serve as a support for the support shoulder and on the other hand are designed to engage with the undercut leg.

[0031] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0032] The case jacket according to the invention comprises a substantially cylindrical case section and a fastening section with a reduced cross-section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0033] According to a further aspect of the invention, the case jacket has a maximum hardness in the region of the attachment section. Thus, at the end of the case facing the base, a characteristic hardness gradient is realized within the material of the case jacket, particularly due to the deep-drawing process, which is functionally very well adapted to the operation of the ammunition. This is because the deep-drawn case jacket is provided with a particularly high hardness at the end closest to the base and significantly softer in the middle or at the projectile end of the case jacket. This improves the bracing of the base to the case jacket and better withstands the high internal pressures during firing.In addition, evasive deformation occurs in the softer central region of the case jacket, which relieves stress in the joint section between the case jacket and the base, which is particularly realized with a positive and / or force-locking connection. A further advantage is that, due to the lower hardness, post-treatment measures such as heat treatments, especially annealing processes, can be omitted in the area of ​​the bullet-side end of the case jacket to soften the material resulting from the hardening during forming. This simplifies the production of the case jacket and makes it more cost-effective.

[0034] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0035] The case jacket according to the invention comprises a substantially cylindrical case section with an open mouth section, also called the case mouth, for receiving a projectile, and a fastening section with a reduced cross-section for connecting to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which has a reduced cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0036] According to a further aspect of the invention, the ratio of the hardness of the mouth portion to the attachment portion is less than 1.0, in particular less than 0.8. During deep drawing of the case jacket, the greatest degree of deformation occurs in the area of ​​the open case mouth, resulting in the greatest hardening there. The open case mouth area is normally used to insert and receive the projectile. However, annealing processes are currently used for this purpose to soften the hardened material again. This procedure is cumbersome and expensive. To avoid this annealing process, one idea of ​​the present invention is to cut off the hardened case mouth area and use the remaining end to connect to the base piece. The normally closed area of ​​the deep-drawn case, which is further processed into the case jacket, is converted to receive the projectile.Since the least increase in hardness occurs in this area during forming or deep drawing, a subsequent annealing process can be omitted.

[0037] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0038] The case jacket according to the invention comprises a substantially cylindrical case section and a fastening section with a reduced cross-section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be perforated or punched out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0039] According to a further aspect of the invention, an annular end face of the sleeve shell facing the base piece, i.e., the fastening section, is produced by cutting to length. The idea is to separate the area of ​​the sleeve shell that has hardened during forming, particularly deep drawing. This simplifies and reduces the cost of manufacturing the sleeve shell.

[0040] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a case jacket is provided for receiving a projectile and for connecting to a base piece for receiving a primer cap for a multi-part cartridge case, in particular with a caliber of less than 20 mm, in particular less than 13 mm. The case jacket according to the invention comprises a substantially cylindrical case section and a case mouth with a reduced cross-section, facing away from the base piece, for receiving the projectile. The case section and the case mouth can be made from one piece. For example, the case jacket is produced by forming, in particular deep drawing.Furthermore, the sleeve shell can have a fastening section opposite the base piece, which is reduced in cross-section compared to the purely cylindrical section and is designed for connection to the base piece. The fastening section can be substantially open. In other words, a base of the sleeve shell can be perforated or punched out, so that an end of the sleeve shell facing the base piece is formed by an annular end face of the fastening section.

[0041] According to a further aspect of the invention, the sleeve mouth is produced by cold forming and is free from any subsequent thermal treatment, in particular a gluing process. Thus, the sleeve shell can be manufactured more cost-effectively and / or with fewer production facilities.

[0042] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a multi-part cartridge case is provided, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0043] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0044] The cartridge case according to the invention comprises a rotationally symmetrical case jacket for receiving a projectile and a base piece fastened thereto by cold forming for receiving a primer cap.

[0045] The case jacket can comprise a substantially cylindrical case section and a fastening section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be punched or stamped out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0046] According to one aspect of the present invention, the material of the base piece has a higher modulus of elasticity than the material of the sleeve shell. This brings significant advantages because when the base piece and sleeve shell are joined, the base piece is pressed from the outside inwards onto the sleeve shell, which is thus also compressed inwards. After the tool, in particular the pressing tool, is removed, both joining partners spring back slightly outwards due to the elasticity of the materials. According to the invention, the springing of the two joining partners after the pressing tool is removed is thus utilized to reinforce the clamping force exerted on each other by the base piece and sleeve shell. With the materials selected in this way, it is ensured that the springback of the sleeve shell is greater than the corresponding springback of the base piece, so that additional preload can be built up between the base piece and sleeve shell.This eliminates the prior art problem of a certain amount of play between the base piece and the sleeve shell. Regarding the cold forming of the connection between the base piece and the sleeve shell, reference is made to the relevant explanations in DE 10 2020 124 559 A1, the contents of which are incorporated herein by reference.

[0047] According to a further aspect of the present invention, which can be combined with the preceding aspects and exemplary embodiments, a cartridge case for ammunition is provided, in particular with a caliber of less than 20 mm, in particular of less than 13 mm.

[0048] Ammunition, also known as a cartridge, typically consists of the following components: a multi-part cartridge case; a primer for igniting the propellant; a propellant charge as an energy carrier; and a projectile to be fired from a firearm. Multi-part cartridge cases typically comprise at least one base piece facing the primer or accommodating the primer, and a separately manufactured case jacket that is firmly connected to the base piece and accommodates the projectile.

[0049] The cartridge case according to the invention comprises a rotationally symmetrical case jacket for receiving a projectile and a base piece for receiving a primer cap.

[0050] The case jacket can comprise a substantially cylindrical case section and a fastening section for connection to the base piece. The case section and the fastening section can be made from a single piece. For example, the case jacket is produced by forming, in particular by deep drawing. Furthermore, the case jacket can have a case mouth opposite the fastening section, which is reduced in cross-section compared to the purely cylindrical section and serves to receive and hold the projectile. The fastening section can be substantially open. In other words, a base of the case jacket can be punched or stamped out, so that an end of the case jacket facing the base piece is formed by an annular end face of the fastening section.

[0051] According to a further aspect of the invention, the base piece is fastened to the sleeve shell by cold forming in such a way that the sleeve shell is elastically deformed. According to the invention, the sleeve shell exerts an elastic deformation restoring force on the base piece resulting from the cold forming, in particular in order to reinforce a holding force or adhesion between the sleeve shell and base piece. The cold-forming joining of the base piece and sleeve shell can be achieved by cold-forming the base piece onto the sleeve shell and, as a result of the pressing, elastically deforming the sleeve shell at least in sections. This results in an elastic deformation restoring force oriented counter to the deformation movement, which prestresses the sleeve shell towards the base piece. This reinforces the attachment of the sleeve shell and base piece to one another.

[0052] Preferred embodiments are specified in the subclaims.

[0053] In the following, further properties, features and advantages of the invention will become clear by describing preferred embodiments of the invention with reference to the accompanying exemplary drawings, in which: Figure 1 is a perspective view of an exemplary embodiment of a cartridge case according to the invention;

[0054] Figure 2 is a sectional view of the cartridge case of Figure 1;

[0055] Figures 3a-3c show schematic diagrams of different manufacturing stages of an exemplary embodiment of a cartridge case according to the invention;

[0056] Figures 4a-4d are schematic diagrams of different manufacturing stages of an exemplary embodiment of a sleeve shell according to the invention by means of an exemplary embodiment of a manufacturing plant according to the invention; and

[0057] Figure 5 is a sectional view of another exemplary embodiment of a cartridge case according to the invention.

[0058] In the following description of exemplary embodiments of the present invention, a cartridge case for ammunition according to the invention is generally designated by reference numeral 1. Basically, a cartridge case 1 according to the invention comprises the following main components: a rotationally shaped case shell 3; and a rotationally shaped base piece 5 with a central recess 7. The case shell 3 is partially received in the central recess 7.

[0059] With reference to Figures 1 and 2, an exemplary embodiment of a cartridge case 1 according to the invention is described in more detail. The case jacket 3 is generally made of metal and has a substantially constant wall thickness along its longitudinal extent. The case jacket comprises a hollow, upwardly open cylindrical section 9, also called a cylindrical case section, and an adjoining neck section 11, which tapers in cross-section relative to the cylindrical section 9 and is designed for coupling to the base piece 5 and is therefore also referred to as a fastening section. The case jacket 3, in particular the cylindrical section 9, is open on a side 13 facing away from the base piece 5.

[0060] The neck section 11 comprises a support shoulder 15 which is inclined with respect to the central axis of rotation M in the direction of the base piece 5 and extends in the radial direction up to a transition 17 which forms the radially innermost point. The support shoulder tapers conically against the weft direction up to the transition 17. Starting from the transition 17, the cross-section of the neck section 11 widens to form an undercut leg 19. The undercut leg 19 widens conically against the weft direction up to a base 23 of the neck section. The base 23 is completely open and essentially formed by an end face 21 forming a ring. As can be seen in Figure 2, the sleeve jacket, i.e. the cylindrical section 9 and the neck section 11, are made from a single piece. For example, the neck section 11 can be produced by deep drawing and prepared for assembly in the base piece 5.

[0061] The base piece 5 has a central recess 7 for receiving the case jacket 3. Opposite the recess 7, the base piece 5 has another central, cylindrical recess 21 in which a primer cap (not shown) is received. In the following description, the recess 7 is referred to as the receptacle 7, and the recess 21 is referred to as the primer cap receptacle 21.

[0062] The base piece 5 also has a central ignition bore 15', which is delimited by an annular jacket 25 of the base piece and opens into both recesses 7, 21. In the embodiment in Figure 2, the jacket 25 forms a web 27. The primer receptacle 7 extends from a primer-side underside 19 of the base piece 5 in the direction of a projectile-side top side 29 of the base piece 5 up to the web 17. From the projectile-side top side 21, the receptacle 5 for the case jacket 3 extends in the direction of the primer-side underside 19 of the base piece 5 up to the web 17. In a further embodiment of the base piece 5, the receptacle 5 can open directly into the primer receptacle 7 without a web being provided in between, as in Figure 1.

[0063] The base piece 5 also includes an extraction groove, which is generally designated by reference numeral 31 below. The extraction groove 31 is formed in an outer side of the base piece 5 and completely surrounds the base piece 5 in the circumferential direction. A firearm ejector can grasp and eject the empty cartridge case 1 via the extraction groove 31 after the projectile has been fired.

[0064] As can also be seen in particular from Figure 2, the fastening section 11 is essentially hourglass-shaped. This allows the positive and / or non-positive connection to the base piece 5 to be realized, since an overlap is formed with respect to the longitudinal direction, so that a separation of the base piece 5 and the sleeve shell 3 in the longitudinal direction or firing direction is prevented. To join the base piece 5 and the sleeve shell 3, the base piece is cold-formed in such a way that the wall surrounding the recess 7, which is formed by bending wings 33, is deformed radially inward, so that the sleeve shell 3 is elastically deformed at least in the region of the fastening section 11 and exerts an elastic deformation restoring force on the base piece 5 resulting from the cold forming.A key aspect of the present invention is that the material of the base piece 5 has a greater modulus of elasticity than the material of the sleeve shell 3. In this way, the springiness of the two joining partners after the pressing tool is removed is utilized to reinforce the clamping force exerted on each other by the base piece 5 and the sleeve shell 3. With the E-modules selected in this way, it is ensured that the springback of the sleeve shell 3 is greater than the corresponding springback of the base piece 5, so that additional prestress can be built up between the base piece 5 and the sleeve shell 3. The problem from the prior art that a certain amount of play can result between the base piece 5 and the sleeve shell 3 is thus prevented. For example, the base piece 5 comprises steel and the sleeve shell brass and / or aluminum. With this material selection, annealing processes in the area of ​​the joining contact can be avoided.

[0065] Referring to Figure 3, the corresponding figures (a), (b) and (c) schematically illustrate the manufacturing process of a cartridge case shell according to the invention and of a multi-part cartridge case 1 according to the invention. Figure 3a shows an intermediate stage of a cartridge case shell 3 according to the invention in the form of a deep-drawn, one-sidedly closed sleeve 35. The sleeve 35 can be produced by several deep-drawing steps starting from a punched blank and has a closed bottom 37 and an opposite open end 39 with a bent-up edge 41.

[0066] Figure 3b shows the case-like intermediate stage 35 in reverse orientation compared to Figure 3a. This is intended to highlight a key inventive concept of the present invention. According to prior art manufacturing methods, the open end 39 would be used to insert and receive the projectile. The closed base 37 would be severed to establish the connection with the base piece 5. According to the present invention, the manufacturing-related hardness profiles resulting from the final case jacket 3 were investigated, and characteristics were identified that are exploited according to the invention to create a cartridge case that is simpler and / or more cost-effective to manufacture and / or to more reliably ensure the functionality of the ammunition.In particular, it was found that by reversing the case-like intermediate stage 35, i.e. by assigning the open end 39, which was actually to be arranged on the projectile side, to the base piece 5 and by assigning the closed base 37, which was to be arranged on the base piece side according to the prior art, to the projectile holder, a cartridge case which is simpler and / or more cost-effective to produce can be created and its functionality can be improved.

[0067] Starting from the intermediate sleeve stage 35 shown in Figure 3b, further forming steps follow to achieve the final shape of the sleeve shell 3 according to the invention, as shown in Figure 3c in the assembled state with the base piece 5. Firstly, the strongly hardened and bent edge region 41 is separated and further formed by pressing into the final shape, which is designed for connection to the base piece 5. Secondly, the base 37 is perforated or punched out on the front side, i.e. in the area of ​​the closed base 37, and also formed by pressing into the final shape with the front indentation 43. For the joining of the base piece 5 and the sleeve shell 3, reference can be made to the relevant explanations in DE 10 2020 134 559 A1, the relevant content of which is incorporated herein by reference.

[0068] In Figure 4, chronologically successive figures 4a to 4d show schematic intermediate steps in the production of a sleeve shell 3 according to the invention using a tooling device, with the focus being on the punching or perforation of the closed base 37 of a further intermediate stage in the form of a formed sleeve 45. With regard to the sleeve intermediate stage 35 according to Figures 3a and 3b, according to the formed sleeve intermediate stage 45 from Figures 4a, 4b, the bent edge 41 has already been severed and the indentation 43 has already been introduced in the region of the closed base 47. To punch the closed base 37, the formed sleeve 45 is inserted into a punching station 50, which has a hollow cylindrical die 47 and a hollow cylindrical elongated punch 49, which is adapted to a dimension of the base section 51 to be separated or punched out.Due to the completed axial relative movement (Figure 4b), a circumferential cutting surface oriented in the longitudinal direction of the sleeve 45 is created, which is indicated by the reference number 53.

[0069] Referring to Figures 4c and 4d, a calibration station 60 is shown in which the sleeve 45 is calibrated and angled to a further intermediate stage. The intermediate product arranged in the calibration station 60 is indicated by the reference numeral 55. The calibration station comprises a pair of press punches 57, 59, which are inserted into the interior of the intermediate product 55 from opposite sides with respect to the longitudinal axis, as well as a pair of hollow cylindrical dies 61, 63 for external shaping and calibration.

[0070] The further exemplary embodiment of a cartridge case 10 according to the invention, shown in Figure 5, differs from the preceding embodiments of the cartridge case 1 in that the case jacket 3 does not rest on the upper side 29 of the base piece 5 in the region of the joining section, in particular in the region of the flexible wings 33 of the base piece 5. According to this embodiment, the case jacket 3 or its bottom 23 of the neck section 11 facing the base piece 5 does not have a radius due to manufacturing reasons. This leads, as can be seen in Figure 5, to an axial gap between the base piece 5, in particular the upper side 29 of the base piece 5, and the case jacket 3, in particular the bottom 23 of the neck section 11 of the case jacket 3. Because the case jacket 3 does not have a radius on the bottom side, it cannot be pressed into the base piece 5 without a gap.Furthermore, it has been found that when the sleeve shell 3 and the base piece 5 are joined together, the gap increases slightly, since the development of the bending line of the sleeve shell 3 increases during joining.

[0071] The features disclosed in the above description, the figures and the claims may be important both individually and in any combination for the realization of the invention in the various embodiments.

[0072] List of reference symbols

[0073] 1 cartridge case

[0074] 3 sleeve jacket

[0075] 5 base piece

[0076] 7 Deepening

[0077] 9 Cylinder section or sleeve section

[0078] 11 Neck section or fastening section

[0079] 13 Page

[0080] 15 Support shoulder

[0081] 15' ignition hole

[0082] 16 Transition

[0083] 19 undercut legs

[0084] 21 Frontal surface

[0085] 23 Floor

[0086] 25 coat

[0087] 27 jetty

[0088] 29 Top

[0089] 31 Extraction groove

[0090] 33 bending brackets

[0091] 35 sleeve-like intermediate stage

[0092] 37 closed floor

[0093] 39 broken end

[0094] 41 bent edge

[0095] 43 Constriction

[0096] 45 formed sleeve as an intermediate stage

[0097] 47 matrix

[0098] 49 stamps

[0099] 51 separated floor section

[0100] 52 punching station

[0101] 53 cutting surface

[0102] 55 Intermediate product

[0103] 57, 59 stamps

[0104] 61, 63 Die center axis

Claims

CLAIMS 1. Base piece for a cartridge case for ammunition with a caliber of less than 20 mm, in particular less than 13 mm or less than 9 mm and more than 6 mm, in particular 6.8 mm, characterized in that the material of the base piece is selected from the list containing structural steel with a carbon content of less than 0.15%, case-hardening steel with a carbon content of less than 0.25%, tempering steel with a carbon content in the range of 0.2% to 0.65% and a heat-treatable aluminum alloy.

2. Soil piece according to claim 1, characterized in that the carbon content is in the range of 0.2% to 0.45%.

3. Base piece according to one of the preceding claims, characterized in that the material is selected and / or designed such that the yield strength of the base piece is dependent on the internal pressure, in particular is proportionally dependent, wherein in particular with lower internal pressure the yield strength decreases.

4. Base piece according to one of the preceding claims, further characterized by a case jacket joining region for connecting to the case jacket and a receptacle for a primer cap facing away from the case jacket, wherein the case jacket joining region is subjected to a temperature treatment, in particular at a temperature exceeding the recrystallization temperature, wherein in particular the primer cap receptacle is free from a temperature treatment.

5. Base piece according to claim 4, characterized in that the case jacket joining area has a lower hardness than the primer cap receptacle, in particular by less than 10%, less than 20% or less than 30%.

6. Cartridge case for ammunition with a calibre of less than 20 mm, in particular less than 13 mm or less than 9 mm and more than 6 mm, in particular 6.8 mm, comprising a rotationally symmetrical case jacket and a cold-formed or integrally formed a base piece produced therewith and designed according to one of the preceding claims for receiving a primer cap.

7. A method for producing a cartridge case for ammunition, in particular with a caliber of less than 20 mm, in particular less than 13 mm, in which a base piece according to one of the preceding claims and a case jacket for receiving a projectile are fastened to one another by cold forming with elastic and / or plastic deformation of at least the case jacket.

8. Method according to claim 7, in which the base piece, in particular before or during the joining, is fixed to a sleeve jacket joining area for connection to the The sleeve jacket is thermally post-treated, in particular by induction or laser.

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