Firearm and method for analyzing a case head

Abstract

The invention relates to a firearm (1) comprising a breechface (2) for supporting a case head (3) of a case (4) of a cartridge (5) when a shot is fired from the firearm (1). The invention also relates to a method for analyzing a case head (3) of a case (4) of a cartridge (5) fired by a firearm (1) having a breechface (2). A more informative, and in particular easy to read, indication of the performance of a cartridge (5) fired from said firearm (1), at least in parts of the cartridge, is obtained in a preferably simple manner by a number of regions (6.1 to 6.5) being formed on the breechface (2), with the regions (6.1 to 6.5) lying in different axially spaced-apart planes (E), in order to determine the pressing force acting between the breechface (2) and the case head (3) during firing on the basis of the impression of the breechface (2) in the case head (3) resulting from firing.

Description

[0001] Firearm and method for analyzing a cartridge case base

[0002] The invention relates to a firearm with a breech face for supporting a cartridge case head during firing from the firearm and a method for analyzing a cartridge case head of a cartridge fired with the aid of a firearm having a breech face.

[0003] WO 2004 / 044515 A2 depicts such a firearm with a breech face designed to support the base of a cartridge case during firing. The breech face features numerous conical protrusions, each with a contoured shape to create a marking on the cartridge case base upon firing. This marking provides information about the firearm used to fire the cartridge. However, this information may not be sufficient to identify the shooter of the firearm in forensic investigations.

[0004] The traceability of cartridges, such as small-caliber ammunition, has become a crucial issue in recent years for non-governmental organizations (NGOs), security organizations, and especially regulatory bodies. Cartridges are also referred to as ammunition in this document. Given the global proliferation of firearms, particularly small arms, and their ammunition, the question arises as to how this ammunition can be traced, for example, to uncover illegal trade flows and / or facilitate law enforcement. One problem is that small-caliber ammunition is often not marked by the manufacturer, making tracing very difficult. NGOs and joint governmental organizations (GGOs) are therefore calling for technologies and, above all, legislation to increase the transparency and traceability of small-caliber ammunition.

[0005] There are illegal trade routes for small-caliber ammunition. A portion of the small-caliber ammunition that ends up in conflict zones and in the hands of criminal organizations originates from illegal sources. Traceability could help uncover the origin and trade routes of this ammunition and then stop these routes. In criminal investigations, the origin of the ammunition can often provide important clues for clarifying a case. Clear marking and traceability allow, for example, governments to better control who buys, sells, or exports ammunition, and consequently ensure that the ammunition does not fall into the wrong hands. Various methods of marking ammunition during its manufacture are known in the prior art, such as...Chemical or biological marking, marking with agents such as gadolinium, marking by mechanical imprinting, marking with lasers or other focused thermal energy, and / or electrotechnical marking, e.g., using RFID tags, are all possible methods of marking ammunition. However, these methods are sometimes very complex and only feasible with considerable effort and expense. Furthermore, depending on the type of marking, some cases can lead to a loss of effectiveness or performance of the weapon itself, such as reduced accuracy. Electrotechnical solutions, in particular, have reliability issues, especially due to the risk of the marking being destroyed or damaged during firing. Other markings can also be destroyed or damaged by firing. Further problems that have prevented any of the aforementioned solutions from becoming widely adopted include, for example...their lack of general acceptance, their lack of interoperability, limited reach of the technologies, lack of connections via appropriate databases, data protection or other regulations, the low added value in operational application, and a lack of doctrinal foundations.

[0006] The invention is based on the objective of providing a firearm with a breech face for supporting the base of a cartridge case during firing, and a method for analyzing the base of a cartridge case fired from a firearm having a breech face, or rather, designing and / or further developing such a method in such a way that the problems of the prior art are avoided or at least reduced. In particular, the invention aims to increase, preferably in a simple manner, the information content of at least parts of a cartridge fired from this firearm, making it particularly easy to read.

[0007] This problem underlying the invention is now solved first by a firearm with a breech face for supporting a cartridge case base when firing from the firearm with the features of claim 1.

[0008] One aspect of the invention essentially lies in the fact that several areas are formed on the breech face, with these areas lying in different axially spaced planes. This allows the contact force acting between the breech face and the cartridge case base to be determined from the impression created by the firing process. This contact force allows conclusions to be drawn about the friction conditions between the cartridge case and the chamber of the firearm during firing. Such information, as well as other additional information, can help to identify a shooter or perpetrator. Due to the appropriate design of these areas, the impression is easily readable, potentially even by a person without any additional tools. It is only necessary to identify the area to which the cartridge case base deformed during firing, as each of the areas is assigned a corresponding contact force.This contact force can be determined through prior measurements and / or simulations. No changes to the ammunition are necessary to determine the contact force; that is, standard commercial cartridges can be used. Changing the shape of the breech face essentially does not alter the weapon's function or ballistics. Nevertheless, the contact force can be reliably determined with every shot.

[0009] Advantageously, the breech face has at least one contour, particularly in the form of a micro-engraving, with axial ridges and / or recesses. These ridges and / or recesses allow the axial flow behavior of the cartridge case head during firing to be influenced in such a way that a unique signature, particularly an identification code, can be created on the cartridge case head.

[0010] The signature increases the information content that can be transmitted through the imprint on the cartridge case head. Furthermore, it enables a simple and unambiguous identification of the firearm and the cartridge case fired from that firearm. Through the signature, especially the identification code, the cartridge case is then marked in relation to the individual firearm. The signature thus constitutes a marking. Due to the high pressure in the chamber of the firearm during firing, the cartridge case and its head are deformed elastically and plastically. This plastic deformation refers to the plastic expansion. Through this plastic expansion, the shape of the cartridge case, including the head, and especially its outer contour, adapts to the shape of the breech face and the inner circumference of the chamber. No modification of the ammunition is necessary for this; that is, commercially available cartridges can be used.This type of cartridge case marking prevents any loss of the firearm's effectiveness, ensuring that the firearm's accuracy is not reduced by the marking process. The alteration of the breech face shape does not fundamentally affect the weapon's function or ballistics. Nevertheless, the marking can be reliably generated with every shot. This provides a solid foundation for the widespread acceptance of this technology. Furthermore, marking the cartridge case head during firing allows for the identification of the cartridge case and the specific firearm from which it was fired, which is of paramount importance in crime investigation. The signature, particularly the identification code, can be converted into a string of characters, such as a numerical code.Such a string is particularly easy to process using data technology and to compare with already known information.

[0011] According to a preferred embodiment of the firearm, a binary identification code can be generated on the cartridge case base by means of the contour. The contour for generating a binary identification code is particularly easy to manufacture, whereby, in particular, similar protrusions and / or recesses are sufficient.

[0012] According to a particularly preferred embodiment of the firearm, the identification code includes a registration code for the firearm. This registration code is often already stored in databases in connection with the corresponding owner of the firearm. This information about the owner of the firearm is particularly important in criminal investigations and can aid in clarifying the facts of a case. The owner of the firearm can also be identified by the marking on the cartridge case base even if only the cartridge case, but not the firearm itself, is found at a crime scene.

[0013] Preferably, a firing pin bore penetrates a central area, the central area being the closest of all the areas to the muzzle of the firearm. A firing pin can be inserted through this firing pin bore to initiate the firing. The firing pin bore and / or the central area are preferably penetrated centrally by the central axis of the breech face. The central axis of the breech face coincides with the central axis of the firearm, in particular the central axis of the chamber and the central axis of the barrel.

[0014] According to a preferred embodiment of the firearm, the contour is formed in one of the areas, particularly the central area. If the contour is located in the area closest to the muzzle of the firearm, especially the central area, then the maximum contact force acts on the contour during firing, so that the contour is particularly well imprinted on the cartridge case base. This improves the legibility of the signature / marking created by the contour. According to a further advantageous embodiment of the firearm, the areas are arranged concentrically to one another. In particular, the areas are annular in shape. Thus, the contact force is evenly distributed circumferentially during firing, which has a positive effect on the pressure distribution within the cartridge case when the propellant charge inside the case ignites.The high precision of the firearm is thus ensured despite the creation of the impression to determine the contact force.

[0015] It can be advantageous if two or more of the areas each have a contour that is preferably similar with respect to the signature that can be generated. This makes the signature easier to determine and more legible. Alternatively, it would also be conceivable to generate different signatures in different areas using different contours in order to increase the information content that can be transmitted via the signatures.

[0016] Advantageously, the areas are each located in planes perpendicular to the central axis of the breech face. The breech face then provides particularly good support for the cartridge case head during firing, meaning the forces generated by the ignition of the propellant charge are absorbed particularly well by the breech face. The areas are identifiable in the impression on the cartridge case head, especially by the edges that define them. Preferably, a transition area parallel to the central axis is formed between each pair of areas located perpendicular to the central axis of the breech face. However, such a transition area could also be angled to the central axis of the breech face.

[0017] Preferably, the axial distances between any two axially adjacent regions are substantially equal. In particular, the radial dimensions of the regions are substantially equal. Manufacturing the sleeve base with these similar regions is then particularly simple, especially possible with the same tool and in a similar manner.

[0018] According to an advantageous embodiment of the firearm, two axially adjacent areas each have an axial distance of 0.01 mm to 0.1 mm, preferably 0.045 mm to 0.055 mm, and particularly preferably 0.05 mm. These values ​​provide a good compromise between good legibility of the imprint and accuracy in determining the contact force. With larger distances, the imprint is more legible, but the contact force is less accurately determined. With smaller distances, the imprint is less legible, but the contact force can be determined more accurately. Furthermore, the axial distances between any two axially adjacent areas are preferably several times, and in particular at least twice, larger than the axial dimensions of the protrusions and / or recesses of the contour.The axial distances between any two axially adjacent areas are therefore of a different order of magnitude than the axial dimensions of the protrusions and / or recesses. In particular, the axial dimensions of the protrusions and / or recesses have values ​​between 0.001 mm and 0.05 mm. This makes it easy to identify which structures in the impression of the sleeve base serve to determine the contact force and by which the signature is formed. Furthermore, this ensures that the contour does not interfere with the determination of the contact force, and vice versa.

[0019] Advantageously, the axial dimensions of the raised areas and / or recesses are at least ten times larger than the roughness of the surface in the contour area. This ensures good legibility of the signature. In particular, no tool, or only a simple one, is required to determine / read the signature. For example, the signature could be read directly by a person or with a simple magnifying glass. Alternatively, a simple camera could suffice to capture a sufficiently sharp image of the signature. If the signature is captured with a camera, the captured images are preferably processed automatically, whereby, among other things, the information contained in the signature, especially the identification code, is determined and further processed.

[0020] Preferably, an outer area with the greatest distance from the central axis of the breech face has the greatest distance from the muzzle. In particular, the breech face has the shape of a stepped cone. The greater the distance of one of the areas from the central axis, the greater its distance from the muzzle. Such a stepped cone is particularly easy to manufacture. For example, to form the areas and / or the contour, especially in the form of a micro-engraving, the breech face is preferably partially abraded with the axial protrusions and / or recesses. The breech face can then initially be manufactured in the same way for all identical firearms, namely, in particular, with only one area lying in a plane perpendicular to the central axis. The abrading is then carried out individually for each firearm, at least for the contour.It is also conceivable that the areas are designed in the same way on identical firearms. Preferably, the chamber, particularly for creating the different areas, is removed using a milling, grinding, and / or polishing process. This further simplifies the removal of the breech face.

[0021] The problem underlying the invention is also solved by a method for analyzing a cartridge case base of a cartridge case fired with the aid of a firearm having a breech face, with the features of claim 13.

[0022] One aspect of the invention essentially lies in the fact that several areas are formed on the breech face, wherein the areas lie in different axially spaced planes, wherein the contact force acting between the breech face and the cartridge case base during firing is determined on the basis of the imprint of the breech face on the cartridge case base caused by the firing, in particular by determining a specific area of ​​the breech face up to which the cartridge case base has deformed in the axial direction during firing.

[0023] This elastic and plastic deformation occurs due to the high pressure inside the cartridge case during firing. Through this plastic deformation, the shape of the cartridge case base conforms to the shape of the breech face, creating an impression of the breech face in the cartridge case base. The contact force during firing provides information about the friction between the cartridge case and the chamber of the firearm. This information, along with other details, can help identify a perpetrator.

[0024] Advantageously, the contact force used to measure moisture on the cartridge case surface during firing can be determined. Even more preferably, the contact force can be used to measure the relative humidity of the air surrounding the firearm during firing. In particular, a certain percentage of moisture condenses on the cartridge case surface due to the correspondingly high relative humidity of the air surrounding the firearm during firing. If the relative humidity at a crime scene is known at what time, the contact force can be used to determine, or at least narrow down, the time of firing.

[0025] Ideally, both the firearm and the ammunition should remain traceable from the factory.

[0026] There are now numerous possibilities for advantageously designing and further developing the firearm and the inventive method for analyzing the cartridge case base according to the invention. Reference is made here to the claims subordinate to claims 1 and 13. In the following, a preferred embodiment of the firearm and the inventive method for analyzing the cartridge case base according to the invention will be explained and described in more detail with reference to the drawing and the accompanying description. The drawing shows:

[0027] Fig. 1 schematically represents an embodiment of the firearm with a cartridge arranged therein in a side view in section before firing the cartridge.

[0028] Fig. 2 shows a schematic representation of a breech face of the firearm from Fig. 1 in a side view, and

[0029] Fig. 3 shows a schematic representation of the breech face of the firearm from Fig. 1 in a top view.

[0030] Fig. 1 shows a firearm 1 with a breech face 2 for supporting a cartridge case head 3 of a cartridge case 4 of a cartridge 5 when firing from the firearm 1. The breech face 2 is shown separately in two different views in Fig. 2 and Fig. 3.

[0031] Several areas 6.1 to 6.5 are formed on the breech face 2. As shown particularly in Fig. 2, these areas 6.1 to 6.5 lie in different axially spaced planes E in order to determine the contact force acting between the breech face 2 and the cartridge case base 3 during firing, based on the impression of the breech face 2 in the cartridge case base 3. Five areas are shown here by way of example: a first area 6.1, a second area 6.2, a third area 6.3, a fourth area 6.4, and a fifth area 6.5.

[0032] The breech face 2 is designed to influence the flow behavior of the cartridge case base 3 for generating the indentation during firing, such that the contact force acting during firing can be determined from the indentation. Before firing, the cartridge 5 is positioned in a chamber of the firearm 1. A barrel of the firearm 1 is connected to the chamber. During firing, a projectile 12 of the cartridge 5, which is connected to the cartridge case 4 before firing, is accelerated in axial direction A by the ignition of a propellant charge 13 of the cartridge 5 located in the cartridge case 4 and is thereby detached from the cartridge case 4. The projectile 12 then travels through the barrel of the firearm 1 and exits through a muzzle 11 of the barrel. The ignition of the propellant charge 13, in particular by means of a firing pin 14 of the firearm 2, creates a high internal pressure of up to approximately 4200 bar within the cartridge case 4.This high internal pressure causes the cartridge case 4 to deform and conform to the breech face 2. This process is called compression. The deformation of the cartridge case 4 consists of an elastic and a plastic component. The plastic component leads to the aforementioned indentation, which is also visible on a cartridge case 4 ejected from the firearm 1 after firing. The material of the cartridge case 4 is sufficiently ductile to achieve the described plastic deformation, namely the corresponding flow behavior. The cartridge case 4 preferably consists of appropriately ductile brass.

[0033] The breech face 2 has at least one contour 7, in particular in the form of a micro-engraving, with axial protrusions 8 and / or recesses 9. The axial flow behavior of the cartridge case head 3 during firing can be influenced by means of the protrusions 8 and / or recesses 9, such that a unique signature, in particular an identification code, can be generated on the cartridge case head 3 by means of the contour 7. The imprint thus also has a negative form of the contour 7. During firing, the cartridge case head 3 then adapts not only at least partially to the areas 6.1 to 6.5 due to its plastic deformation, but also to the contour 7.

[0034] The signature, in particular the identification code, can then be read, for example, after the cartridge case 4 is found at a crime scene. The signature, in particular the identification code, can be read by a person and / or by appropriate means, e.g., optical scanning. The signature, in particular the identification code, is converted into the contour 7 with the raised areas 8 and / or recesses 9 for the production of the breech face 2, namely by appropriately forming the contour 7. The contour 7 is formed in such a way that the signature, in particular the identification code, can be read without errors in the imprint on the cartridge case base 3 after firing.

[0035] Using contour 7, for example, a binary identification code can be generated on the cartridge case base 3. After firing, the imprint on the cartridge case base 3 in the signature area then only has two states, namely, for example, raised and removed, whereby these two states are converted into zeros and ones during the reading process.

[0036] In particular, a system similar to that used for barcodes can be employed for encoding, where a raised area 8 or a recess 9 represents a black line or a space between two black lines. The signature, especially the identification code, contains a registration code for firearm 1. Other information may also be stored in the signature, especially the identification code.

[0037] A firing pin bore 10 penetrates a central, in particular the first, area 6.1, wherein the central area 6.1 has the smallest distance of the areas to the muzzle 11 of the firearm 1. The firing pin 14 of the firearm 2 can be passed through the firing pin bore 10 to initiate firing, in particular to ignite the propellant charge 13. It would also be conceivable that another of the areas has the smallest distance of the areas to the muzzle of the firearm, but the support of the cartridge case head 3 during firing is least affected by the special shape of the breech face 2 if the central area 6.1 has the smallest distance of the areas to the muzzle 11 of the firearm 1.

[0038] Contour 7 is formed in one of the regions 6.1 to 6.5, in particular the central region 6.1. Contour 7 has, in particular, radially oriented recesses 9, which alternate in the circumferential direction U with intervening radially oriented protrusions 8. The protrusions 8 and / or recesses 9 can also have the form of circular ring sectors. It is also conceivable that the protrusions 8 and / or recesses 9 are arranged parallel to each other.

[0039] Areas 6.1 to 6.5 are arranged concentrically. Areas 6.1 to 6.5 are annular in shape. Other arrangements, e.g., asymmetrical arrangements and / or other shapes of the areas are conceivable; for example, the outer boundary of at least one of the areas could have a rectangular shape.

[0040] Two or more of the areas 6.1 to 6.5 each have a contour 7 that is preferably identical with respect to the generable signature. Fig. 3 shows that the first area 6.1, the third area 6.3, and the fourth area 6.4 have a contour 7 that is identical with respect to the generable signature. The distances between the individual protrusions 8 and / or recesses 9, or their circumference, are greater the further they are from the central axis M of the impact surface 2. In the first area 6.1 and the third area 6.3, the contour 7 is formed radially centered in the respective area 6.1, 6.3. In the fourth area 6.4, the contour 7 is formed only in the outer edge region. However, different areas could also have different contours with differing information content. The areas 6.1 to 6.5 each lie in planes E perpendicular to the central axis M of the impact surface 2.Alternatively, the areas could also be formed in planes at an angle to the central axis M and / or curved areas could be provided. Between two adjacent areas of regions 6.1 to 6.5, the impact base 2 preferably has a cylindrical outer circumference.

[0041] The axial distances between any two axially adjacent regions 6.1 to 6.5 are essentially equal. The radial dimensions of regions 6.1 to 6.5 are also essentially equal. "Essentially" in this context means that deviations of up to 10% from these equal values ​​are permissible.

[0042] Two axially adjacent regions 6.1 to 6.5 each have an axial distance of 0.01 mm to 0.1 mm, preferably of 0.045 mm to 0.055 mm, particularly preferably of 0.05 mm.

[0043] The axial distances between any two axially adjacent areas 6.1 to 6.5 are many times larger than the axial dimensions of the protrusions 8 and / or recesses 9 of the contour 7. In particular, the axial dimensions of the protrusions 8 and / or recesses 9 have values ​​between 0.001 mm and 0.05 mm.

[0044] The axial dimensions of the protrusions 8 and / or recesses 9 are at least 10 times larger than the roughness of the impact base 2 in the area of ​​the contour 7.

[0045] An outer region 6.5, with the greatest distance of regions 6.1 to 6.5 from the central axis M of the breech face 2, has the greatest distance of regions 6.1 to 6.5 from the mouth 11. The breech face 2 has the shape of a stepped cone.

[0046] The butt plate 2 is removed, in particular by a milling process, a grinding process, and / or a polishing process, to create areas 6.1 to 6.5. Other removal methods are conceivable. Alternatively, areas 6.1 to 6.5 could also be produced by other (primary forming) processes for manufacturing the butt plate 2 without removal. The contour 7 with the protrusions 8 and / or recesses 9 is produced, in particular, by electrical discharge machining (EDM), spark erosion (EDM), milling, and / or by an engraving tool, whereby the butt plate 2 is removed accordingly. Other methods for producing the contour 7 are conceivable. The contour 7 could also be produced by other methods without removal.

[0047] The following describes a method for analyzing the cartridge case base 3 of the cartridge case 4 of the cartridge 5 fired using the firearm 1 having the breech face 2.

[0048] The contact force acting between the breech face 2 and the cartridge case base 3 during firing is determined based on the impression of the breech face 2 in the cartridge case base 3 caused by the firing, in particular by determining a specific area 6.1 to 6.5 of the breech face 2 up to which the cartridge case base 3 has deformed in axial direction A during firing.

[0049] Each area 6.1 to 6.5 is assigned a contact force. If the impression on the cartridge case head 3 still shows the third area 6.3, but not the fourth area 6.4, then the contact force lies between the value corresponding to the third area 6.3 and the value corresponding to the fourth area 6.4. The axial distances between areas 6.1 to 6.5 ensure a corresponding level of accuracy in determining the contact force. The contact force values ​​corresponding to areas 6.1 to 6.5 are determined through tests and / or calculations, e.g., simulations, whereby areas 6.1 to 6.5 are designed according to the expected contact forces and the desired accuracy in their determination. In particular, the outer edges of areas 6.1 to 6.5 are imprinted into the cartridge case head 3 during firing, so that corresponding shapes are easily recognizable in the impression.

[0050] The contact force is used to determine the moisture content on the surface of cartridge case 4 during firing, and / or the relative humidity of the air surrounding the firearm 1 during firing is determined from the contact force. The corresponding relationships are first established through experiments and / or calculations, e.g., simulations. The moisture content on the surface of cartridge case 4 affects the friction between the cartridge case 4 and the chamber of the firearm 1, and thus also the contact force during firing. The moisture content on the surface of cartridge case 4 depends on the relative humidity of the air surrounding the firearm 1 during firing. (Reference symbol list)

[0051] 1 firearm

[0052] 2 impact floor

[0053] 3 sleeve bottoms

[0054] 4 Sleeve

[0055] 5 cartridges

[0056] 6.1 first, middle area

[0057] 6.2 second area

[0058] 6.3 third area

[0059] 6.4 fourth area

[0060] 6.5 fifth area

[0061] 7 Contour

[0062] 8 surveys

[0063] 9 exceptions

[0064] 10 firing pin bore

[0065] 11 Mouth

[0066] 12 projectiles

[0067] 13 propellant charge

[0068] 14 firing pins

[0069] E levels

[0070] M Central axis of the shock absorber 2

[0071] A Axial direction

[0072] U circumferential direction

Claims

Patent claims 1. Firearm (1) with a breech face (2) for supporting a cartridge case head (3) of a cartridge case (4) of a cartridge (5) during firing from the firearm (1), characterized in that several areas (6.1 to 6.5) are formed on the breech face (2), wherein the areas (6.1 to 6.5) are located in different axially spaced planes (E) in order to determine the contact force acting between the breech face (2) and the cartridge case head (3) during firing, based on the impression of the breech face (2) in the cartridge case head (3) created by firing.

2. Firearm (1) according to claim 1, characterized in that the breech face (2) has at least one contour (7), in particular in the form of a micro-engraving, with axial protrusions (8) and / or recesses (9), wherein the axial flow behavior of the cartridge case base (3) during firing can be influenced by means of the protrusions (8) and / or recesses (9) in such a way that a unique signature, in particular according to an identification code, can be produced on the cartridge case base (3) by means of the contour (7).

3. Firearm (1) according to one of the preceding claims, characterized in that a firing pin bore (10) penetrates a central area (6.1), wherein the central area (6.1) has the smallest distance of the areas to a muzzle (11) of the firearm (1).

4. Firearm (1) according to claim 2 or 3, characterized in that the contour (7) is formed in one of the areas (6.1 to 6.5), in particular the middle area (6.1).

5. Firearm (1) according to one of the preceding claims, characterized in that the areas (6.1 to 6.5) are arranged concentrically to each other and / or wherein the areas (6.1 to 6.5) are formed in an annular shape.

6. Firearm (1) according to one of claims 2 to 5, characterized in that two or more of the areas (6.1 to 6.5) each have a contour (7) that is preferably similar with respect to the signature that can be produced.

7. Firearm (1) according to one of the preceding claims, characterized in that the areas (6.1 to 6.5) each lie in planes (E) perpendicular to the central axis (M) of the breech face (2).

8. Firearm (1) according to one of the preceding claims, characterized in that the axial distances between each pair of axially adjacent regions (6.1 to 6.5) are substantially the same and / or wherein the dimensions of the regions (6.1 to 6.5) in the radial direction are substantially the same.

9. Firearm (1) according to one of the preceding claims, characterized in that two axially adjacent areas (6.1 to 6.5) each have an axial distance of 0.01mm to 0.1mm, preferably 0.045mm to 0.055mm, particularly preferably 0.05mm.

10. Firearm (1) according to one of claims 2 to 9, characterized in that the axial distances between each of two axially adjacent areas (6.1 to 6.5) are many times larger than the axial dimensions of the protrusions (8) and / or recesses (9) of the contour (7), in particular wherein the axial dimensions of the protrusions (8) and / or recesses (9) have values ​​between 0.001mm and 0.05mm.

11. Firearm (1) according to one of claims 2 to 10, characterized in that the axial dimensions of the protrusions (8) and / or recesses (9) are at least 10 times larger than the roughness of the breech face (2) in the area of ​​the contour (7).

12. Firearm (1) according to one of the preceding claims, characterized in that an outer region (6.5) with the greatest distance of the regions (6.1 to 6.5) to the central axis (M) of the breech face (2) has the greatest distance of the regions (6.1 to 6.5) to the muzzle (11) and / or wherein the breech face (2) has the shape of a stepped cone.

13. Method for analyzing the base of a cartridge case (3) of a cartridge case (4) of a cartridge (5) fired by means of a firearm (1) having a breech face (2), in particular according to one of the preceding claims, characterized in that several areas (6.1 to 6.5) are formed on the breech face (2), wherein the areas (6.1 to 6.5) lie in different axially spaced planes (E), wherein the impression of the breech face (2) in the cartridge case base (3) resulting from the firing process is used to determine the The contact force acting between the breech face (2) and the cartridge case head (3) during firing is determined, in particular by determining a specific area (6.1 to 6.5) of the breech face (2) up to which the cartridge case head (3) has deformed in the axial direction (A) during firing.

14. Method according to claim 13, characterized in that moisture on the surface of the sleeve (4) is determined from the contact force during firing and / or that humidity of an air atmosphere surrounding the firearm (1) during firing is determined from the contact force.

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