Patent Publication Number: US-2022236028-A1

Title: Devices and methods for extraction of high pressure cartridge casings

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 16/995,395, filed Aug. 17, 2020 and claims the benefit under 35 U.S.C. § 119(e) of the earlier filing date of U.S. Provisional Patent Application No. 62/887,139 filed on Aug. 15, 2019, and the disclosures of each are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to rifle chamber modifications or inserts for improving reliability and performance. 
     BACKGROUND OF THE INVENTION 
     A rifle chamber and cartridge are subjected to rapid changes in temperature and pressure when a bullet is fired and, subsequently, the spent cartridge casing is ejected from the chamber. Modern rifle designs may employ even greater pressures than previous designs. Moreover, there may be a variety of dimensional variations for cartridges of a given caliber; such variations may not be readily accommodated by a single rifle. 
     SUMMARY OF THE INVENTION 
     A gun barrel assembly comprises a gun barrel, a chamber formed at a proximate end of the gun barrel, and a chamber insert. The gun barrel is formed of a material comprising steel and configured for firing a cartridge within a range from .17-.50 caliber. The chamber insert is affixed in the chamber, the chamber insert dimensioned to extend along a body of a cartridge case and terminate proximate a neck of the cartridge case accommodated and fired by the gun barrel assembly. The chamber insert defines an interior surface for interfacing the cartridge casing, and the chamber insert is formed of a material comprising one of a tungsten carbide, a tungsten heavy alloy, and a bulk metallic glass, and the material comprising an elastic modulus that is from about 60×10 6  psi to about 200×10 6  psi. 
     A feature and benefit of embodiments is a gun barrel assembly wherein the chamber insert is configured to accommodate and extract a cartridge casing comprising steel due to the chamber insert comprising an elastic modulus of about two to six times greater than the elastic modulus of the cartridge casing. 
     In embodiments, the gun barrel assembly further includes a cartridge comprising a cartridge casing formed of a material comprising steel, wherein the elastic modulus of the chamber insert is from about two to six times greater than the elastic modulus of the cartridge casing. 
     In embodiments, the gun barrel assembly further includes said gun barrel shrunk fit onto said chamber insert. A feature and benefit of embodiments is a gun barrel assembly wherein the insert comprises a radial wall thickness that is less than one half of a diameter of a body portion of the chamber insert. 
     In other embodiments, a gun barrel assembly comprises a gun barrel, a chamber disposed at the proximal end of the gun barrel, and a dynamic insert mounted in the chamber. The gun barrel is configured for firing a cartridge within a range from .17-.50 caliber. The chamber includes a proximal angled wall, a body, and a neck. The dynamic insert is mounted in the chamber and including a wall portion, an angled waist, and an end web, said wall portion defining a plurality of slits that extend through a thickness of said wall portion, said plurality of slits extending axially from an end web disposed at an axial end of the dynamic insert, the dynamic insert being configured to surround an entirety of a cartridge casing. The dynamic insert is slidingly mounted in the chamber and is configured to radially contract and secure the cartridge casing when in a battery configuration and to radially expand and release the cartridge casing when in an out-of-battery configuration. The angled waist interfaces with the proximal angled wall to move the dynamic insert between the battery configuration and the out-of-battery configuration. 
     In embodiments, the gun barrel assembly further includes the slits dividing the dynamic insert into six segments. 
     In embodiments, the gun barrel assembly further includes the dynamic insert extending substantially the same axial length as the chamber. 
     In embodiments, the gun barrel assembly further includes the chamber having a proximal body portion extending substantially axially from the proximal angled wall and comprising a first diameter; and a distal neck portion extending substantially axially from the proximal angled wall toward the barrel and comprising a second diameter that is less than the first diameter. 
     In embodiments, the gun barrel assembly further includes the dynamic insert extending axially along both the body portion and the neck portion. 
     In embodiments, the gun barrel assembly further includes wherein the chamber defining a distal angled wall connecting the chamber to the barrel; and wherein the dynamic insert has an angled fore end for interfacing with the distal angled wall to move the dynamic insert between the battery configuration and the out-of-battery configuration. 
     In embodiments, the gun barrel assembly further includes the end web is a proximal end web formed at a proximal end of the dynamic insert; and the dynamic insert includes a distal end web formed at a distal end of the dynamic insert. 
     A feature and benefit of embodiments is a gun barrel assembly comprising the chamber and dynamic insert configured to adjustably accommodate and fire cartridges of different sizes. 
     In still other embodiments, a gun barrel assembly comprises a gun barrel, a chamber disposed at a proximal end of said gun barrel, and an adaptable insert. The gun barrel is configured for firing a cartridge within a range from .17-.50 caliber. The chamber comprises an inner wall comprising a proximal angled wall. The adaptable insert includes a wall portion, an angled waist, and an end web, said wall portion comprising a plurality of segments with slits between the segments, the slits extending through a thickness of said wall portion, the slits extending axially from an end web disposed at an end portion of said wall portion, said adaptable insert being configured to surround at least a portion of a cartridge casing. The adaptable insert is slidingly mounted in the chamber and defines a radial gap between the wall portion and the inner wall of the chamber, and is configured to radially contract and chamber a first cartridge casing when in a battery configuration and to radially expand and release the first cartridge casing when in an out-of-battery configuration. The angled waist interfaces with the proximal angled wall to move the adaptable insert between the battery configuration and the out-of-battery configuration. The adaptable insert is configured to accommodate and fire cartridges of different sizes from the chamber and the radial gap varies when the adaptable insert holds different size cartridges of the same caliber. 
     A feature and benefit of embodiments is a gun barrel assembly wherein the adaptable insert is configured to selectively accommodate and fire any of at least a first cartridge and a second cartridge in the chamber, the second cartridge comprising one or more dimensions different than the first cartridge. 
     In embodiments, the gun barrel assembly further includes the one or more different dimensions including a body diameter, an axial length, and a headspace. 
     In embodiments, the gun barrel assembly further includes the first and second cartridges being .22 caliber, the first cartridge has a body diameter of 0.227 in. and the second cartridge has a body diameter of 0.243 in. 
     In embodiments, the gun barrel assembly further includes the adaptable insert defining an expansion gap between the plurality of slits when holding a cartridge; wherein the expansion gap is about 0.001 in. when holding the first cartridge and the expansion gap is about 0.010 in. when holding the second cartridge. 
     In embodiments, the gun barrel assembly further includes the chamber defining a distal angled wall connecting the chamber to the barrel; and wherein the adaptable insert has an angled fore end for interfacing with the distal angled wall to move the adaptable insert between the battery configuration and the out-of-battery configuration. 
     In embodiments, the gun barrel assembly further includes the end web being a proximal end web formed at a proximal end of the insert; and the adaptable insert includes a distal end web formed at a distal end of the adaptable insert. 
     The above summary of the various representative embodiments of the invention is not intended to describe each illustrated embodiment or every implementation of the invention. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the invention. The Figures in the detailed description that follow more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which: 
         FIG. 1  is a partial cross-sectional view of an example static insert in a barrel of a rifle in accord with embodiments of the present disclosure. 
         FIG. 2  is a partial cross-sectional view of another embodiment of a static insert in the barrel of  FIG. 1 . 
         FIG. 3  is a partial cross-sectional view of an example dynamic insert in a barrel of a rifle in accord with other embodiments of the present disclosure in a battery configuration. 
         FIG. 4  is a view of the embodiment of the dynamic insert of  FIG. 3  in a non-battery configuration. 
         FIG. 5  is a front isometric perspective view of the embodiment of the dynamic insert of  FIG. 4 . 
         FIG. 6  is a rear isometric perspective view of the embodiment of the dynamic insert of  FIG. 4 . 
         FIG. 7  is a partial cross-sectional view of another example adaptable insert in a barrel of a rifle in accord with other embodiments of the present disclosure when mounting a cartridge of a first size. 
         FIG. 8  is a partial cross-sectional view of the embodiment of the dynamic insert of  FIG. 6  when mounting a cartridge of a second size. 
         FIG. 9  is a plan view of an example .22 caliber long rifle cartridge. 
         FIG. 10  is a plan view of an example .22 caliber long rifle chamber. 
         FIG. 11  is a plan view of an example of a .22 caliber super cartridge. 
         FIG. 12  is a plan view of an example .22 caliber super chamber. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been depicted by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     As shown in  FIG. 1  and generally applicable to any embodiments of the present disclosure, an example gun barrel assembly  20  partially chambers a cartridge  80 . The cartridge  80  is provided with a cartridge case  82  that includes propellant inside the case  82  and a bullet  84 . The cartridge case  82  has a body  86 , an angled shoulder  88 , and a neck  90 . A proximal end  32  of the gun barrel  34  includes a chamber  28  that holds the cartridge case  82  and allows the cartridge case  82  to be ejected. The gun barrel  34  is in a generally cylindrical shape with a bore  36  extending axially to guide the bullet  84  of the cartridge  80  when fired as a projectile. The disclosed embodiments are beneficial for extracting a cartridge case  82  in ‘high pressure’ weapons systems (e.g., firing pressures of 60,000 pounds per square inch (psi) or more). Such high pressure weapons systems impart significant strain on the gun barrel assembly  20  due to high temperatures, high pressures, shock loads, and the like. Various embodiments have utility when using steel or other materials for a cartridge case  82 . Such steel cases may offer strength, cost, and manufacturability benefits as compared to conventional configurations, such as e.g. a brass case, particularly for high pressure weapon systems. 
     Referring to  FIGS. 1 and 2 , the gun barrel assembly  20  includes a chamber  28  mounting a static chamber insert  30 ,  60  at a proximal end  32  of a gun barrel  34  that defines a bore  36  at a distal end thereof. The static chamber insert  30 ,  60  includes an inner surface  42  that defines a body portion  44 , an angled shoulder portion  46 , and a neck portion  48  that is of a smaller diameter than the body portion  44 . The static chamber insert  30  may be formed from a material with a high elastic modulus, such as tungsten or tungsten alloys. The static chamber insert  30  also defines a radial wall thickness  50 . In the illustrated embodiments, the wall thickness  50  is less than a thickness  52  of the chamber  28  and less than half of a diameter  54  of the body portion  44 , although these relative dimensions may vary, including embodiments wherein the static chamber insert  30  is effectively an inner liner for the chamber  28 , and embodiments where the chamber  28  is entirely comprised by the static chamber insert  30 . 
     In the embodiment shown in  FIG. 1 , the static chamber insert  30  is dimensioned with a length  56  to substantially coextend with a high pressure cartridge case  82 , including coextending with one or more of the angled shoulder  88  and the neck  90 . In the embodiment shown in  FIG. 2 , a static chamber insert  60  is dimensioned to extend over a portion of the full length of the casing  82 , with the static chamber insert  60  having an axial length  62  that is coextensive with the body  86  of the cartridge case  82 . A distal end  64  of the static chamber insert  60  terminates proximate the shoulder  88  of the cartridge, such that the chamber  28  of the gun barrel assembly  20  may define an inner shoulder portion  66  and neck portion  68  for receiving the cartridge  80 . In other embodiments, the static chamber insert  60  may extend along about 50% or about 75% of the length of the body  86  of the cartridge case  82 . This embodiment is otherwise substantially similar to  FIG. 1 . 
     As noted, the static chamber insert  30 ,  60  is fabricated from a material having a high modulus of elasticity, defined herein as a modulus of elasticity that is at least 60×10 6  pounds per square inch, and a sufficiently high yield strength. In some embodiments, the static chamber insert  30 ,  60  comprises a tungsten alloy, a bulk metallic glass (“BMG”), or other material exhibiting comparable elastic modulus and yield strength. For example, the static chamber insert  30 ,  60  may comprise one of a tungsten carbide and a tungsten heavy alloy. In certain embodiments tungsten carbide includes tungsten and carbon with tungsten comprising about 50-96% of the alloy. Other tungsten-based materials are contemplated including other ratios of tungsten-to-carbon and materials including about 0-20% of cobalt and other elements. A tungsten heavy alloy may be formed from about 80% or more of tungsten, about 90% or more of tungsten, or about 95% or more of tungsten. Such tungsten heavy alloys may include about 0-20% or 0-10% of one or more of iron, copper, nickel, molybdenum, or similar elements. A BMG is a type of amorphous metal alloy (i.e., having a disordered atomic-scale structure) that is based on one or more of zirconium, palladium, iron, titanium, copper, and magnesium. BMG typically is formed from two, three, four or more elements that are cooled with a disordered state instead of a crystalline structure. BMG is formed with a thickness of about 20-50 microns up to about 2 cm. 
     In certain embodiments, the static chamber insert  30 ,  60  is affixed within the chamber  28  of the gun barrel assembly  20 , which may be formed of various materials such as steel alloys. In some embodiments, the gun barrel  34  and chamber  28  are shrink fit onto the static chamber insert  30 ,  60 . For example, the gun barrel  34  and chamber  28  may be heated to expand, placed over the static chamber insert  30 ,  60 , and subsequently shrink during cooling to provide a permanent interference fit. In other embodiments, the static chamber insert  30  may be mounted in a press fit or other similar permanent or semi-permanent arrangements including those used in the firearm industry for assembling barrels, bolts, and accessories thereto. Further embodiments may include a fastener through a radial cross-drill perpendicular to the axis of the gun barrel  34  or the chamber  32 , a cross pin extending off-axis through a majority or all of the barrel, a roll pin mounted around the barrel in a groove, or the like. The above mounting arrangements may be supplemented by set screws, collars, saddles, or the like. . 
     Functionally, the expansion and relaxation of the disclosed chamber insert are reduced relative to that of the high pressure cartridge casing. The elastic modulus of the steel casing is typically about 30×10 6  pounds per square inch. After discharge of the cartridge  80 , the case  82  undergoes a relaxation in strain, whether the deformation of the case was elastic or plastic. Meanwhile, in certain embodiments of this invention, the expansion and relaxation of the chamber  30  is substantially less due to the high modulus of elasticity. Accordingly, the cartridge case  82  will relax more than the chamber  30 , enabling the cartridge casing  82  to be removed from the chamber  30  without excessive force requirements. 
     In various embodiments of the disclosure, a static chamber insert  30 ,  60  is formed from a material having a modulus of elasticity much higher than the case of the high pressure cartridges to be contained therein. In this way, the expansion as well as the relaxation of the chamber is reduced relative to the cartridge case  82  such that the magnitude of the case ‘relaxation’ can be reduced and still result in a clearance with the chamber post-firing. Theoretically, a chamber wall (or insert) that exhibits zero radial deflection under load would enable the use of any cartridge case material, including any steel alloys, because there will always be a relaxation in strain that follows the modulus of elasticity slope while the dimension of the chamber remains fixed, even after plastic deformation. Because such a zero-deflection chamber wall or insert is not feasible, embodiments of the present disclosure utilize high modulus materials, such as tungsten carbide, tungsten heavy alloys, or BMG, as elastic strain is driven primarily by the elastic modulus value. In some embodiments, chamber materials exceeding 98×10 6  pounds of force per square inch (psi) are utilized—more than three times that of steel alloys (typically about 30×10 6  psi). In some embodiments, the static chamber insert  30 ,  60  is formed from materials having elastic moduli that are within a range from about 60×10 6  psi up to about 200×10 6  psi, in other words, ranging from about two times to six times that of steel alloy cartridge casing materials. Because of the high elastic modulus of the static chamber insert  30 ,  60 , the use of cartridge cases  82  having a wide range of material properties is enabled. 
     It will be appreciated that, due to similar material properties between conventional weapon barrels and chambers (formed of steel or steel alloys) and steel cartridge cases, there is a propensity for steel cases to form a quasi-interference fit with the chamber of the weapon when chamber pressures exceed the yield strength of the cartridge case material. Such quasi-interference fits can result in excessive chamber-case extraction forces (e.g., greater than 500 pounds of force for 7.62×51 mm-based weapon systems). The excessive chamber-case extraction forces increase the stresses required of extractors, thereby reducing extractor life. By contrast, the present disclosure results in significantly reduced extraction forces, such as about 150 pounds of force or less for 7.62×51 mm-based weapon systems. 
     Because of the similarity in the elastic/plastic deformation properties of the materials in conventional arrangements, i.e. a steel barrel and chamber (elastic) and steel case (plastic), both the cartridge case  82  and the chamber (or insert) tend to deflect to the same extreme deflection at their interface during firing of the cartridge  80 , then undergo relaxations afterwards (following the Modulus of Elasticity slope), such that after firing, the cartridge case  82  may have the same dimension at the interface of the chamber  102 . If the cartridge case  82  yield strength is insufficiently low, there is not enough ‘relaxation’ possible for the case  82  to result in a post-firing diameter smaller than the diameter of a static chamber (or chamber insert) that only undergoes elastic deformation during firing. This exacerbates the problem of the quasi-interference fit and attendant excessive extraction forces. By contrast, embodiments of the present disclosure maintain a sufficient difference between the respective elastic moduli of the cartridge case  82  and the static chamber insert  30 ,  60  so as to circumvent this issue. 
     Referring to  FIGS. 3-6 , another embodiment of a gun barrel assembly  100  includes a dynamic chamber insert  110  inserted to a chamber  102  at a proximal end  103  of a gun barrel  104 . In  FIG. 3 , the dynamic chamber insert  110  is depicted in an out-of-battery or “open” configuration  106  exaggerated in an axial direction for illustrative purposes; typically the out-of-battery configuration  106  occurs with the dynamic chamber insert  110  slightly backed out before full engagement with the chamber  102 . In  FIG. 4 , the dynamic chamber insert  110  is depicted in a battery or “closed” configuration  108  ready for firing. The dynamic chamber insert  110  is so-named because it is slidingly engaged to the chamber  102  of the gun barrel  104  and is also configured to radially expand and contract about the cartridge case  82  of the cartridge  80 . Thus, the cartridge  80  is held in the dynamic chamber insert  110  in the manner of a collet. 
     In certain embodiments, the dynamic chamber insert  110  includes a wall portion  112  that defines a plurality of slits  114  that extend through a thickness of the wall portion  112 . In certain embodiments, the plurality of slits  114  extend in an axial direction parallel to a bore axis  118  of the gun barrel  104 . In certain embodiments, the dynamic chamber insert  110  includes at least one web  122  at an axial end from which the plurality of slits  114  extend. In some embodiments, the at least one web  122  is disposed at a proximal end  124  of the dynamic chamber insert  110 ; in some embodiments, the at least one web  122  is disposed at a distal end  126  of the dynamic chamber insert  110 . In embodiments with one web  122 , the slits  114  may extend to the opposite end of the insert  110  (e.g., from the proximal end  124  to the distal end  126 ), such that the opposite end of the insert  110  is open, in other words, with no interconnecting web. In other embodiments, both the proximal end  124  and the distal end  126  include a respective web  122 , with the slits  114  alternating in origination from the proximal end  124  and the distal end  126 . In certain embodiments, the web  122  acts to integrate the dynamic chamber insert  110  so that the dynamic chamber insert  110  is an integrally formed unitary component such as the dynamic chamber insert  110  shown in  FIGS. 5-6 . As best shown in  FIGS. 5-6 , in certain embodiments the dynamic insert  110  may be divided into segments  128 , for example six segments  128  of equal size, spread about the circumference of the dynamic insert  110 . The at least one web  122  therefore is defined by axial ends of the segments  128  and contributes to a resilient bias of the dynamic insert  110  in a radially outward direction, i.e., expansion. The dynamic chamber insert  110  has an axial length L 1 , whereas the slits  114  extend for a relatively shorter axial length L 2 . The length L 2  of the slits  114  may be from about 80% to about 99% of the length L 1  of the dynamic chamber insert  110 , and in certain embodiments may be about 95% of the length L 1 . In certain embodiments, the slits  114  do not extend the entire length L 1 , such that the web  122  bridges the slits  114  between two corresponding legs of each segment. In this manner, the dynamic chamber insert  110  is unitary as a continuous serpentine cord of material. The unitary nature of the dynamic chamber insert  110  provides ease of manufacturing assembly, as well as disassembly/reassembly or replacement during maintenance of the gun barrel  104 . 
     Referring to  FIGS. 3 and 4 , the dynamic chamber insert  110  is sized to closely fit within the chamber  102  of the gun barrel assembly  100 . The chamber  102  has an inner wall  130  defining a foot portion  132  and a body portion  134  connected by a proximal angled wall  136 . A distal angled wall  138  connects the body portion  134  of the chamber to the barrel  104 . Correspondingly, the dynamic chamber insert  110  extends axially along the inner wall  130  and includes an angled waist  140  for interfacing with the proximal angled wall  136  and, in some embodiments, also includes an angled fore end  142  for interfacing with the distal angled wall  138 . By interfacing with the proximal angled wall  136  in this manner, the dynamic chamber insert  110  has freedom to radially expand when moved in an axially rear direction A R  (e.g., when in the out-of-battery configuration  106  before and after firing) and is forced to radially contract when moved in an axially forward direction A F  (e.g., when loading a cartridge and moving to the battery configuration  108 ). The slits  114  define a variable expansion gap  144  ( FIG. 5 ) between portions of the wall portion  112  that varies to be relatively wider in the out-of-battery configuration  106  than in the battery configuration  108 . In some embodiments, the foot portion  132  of the chamber  102  may have various guiding or retention features to engage with the dynamic chamber insert  110  (or a complementary structure thereon) to prevent accidental back-out of the dynamic chamber insert  110 ; such structures may be a catch, complementary indent-detent, slot, or the like. 
     The dynamic chamber insert  110  is resiliently biased toward a rest position with an inner diameter  150  that is greater than the cartridge case  82  diameter, resulting in ready release of the cartridge case  82  once the dynamic chamber insert  110  moves axially in rearward direction A R . The axial movement and resulting radial contraction and expansion of the dynamic chamber insert  110  may be driven, for example, by the action of the bolt (not shown). Therefore, the dynamic chamber insert  110  automatically expands radially during extraction of the cartridge case  82 . When the cartridge  80  is loaded to the battery configuration before firing, the dynamic chamber insert  110  contracts radially to the dimension of the cartridge  80  and firmly holds the cartridge case  82 . In certain embodiments, the dynamic chamber insert  110  includes an inner wall  152  generally shaped to correspond to the cartridge  80  and surround the cartridge  80 , including a wide body portion  154 , a reduced-diameter neck portion  156 , and an angled surface  158  connecting the two portions. 
     In certain embodiments, the dynamic chamber insert  110  is sized to surround a substantial entirety of the cartridge case  82 , e.g., extending along the entire body  82 , the body  82  and the shoulder  88 , or the entire cartridge case  82  including the shoulder  88  and the neck  90 . In other embodiments, the dynamic chamber insert  110  may extend along only a portion of the body  82  of the cartridge case  82 . The wide body portion  154  is sized to closely correspond to a diameter  160  of the inner wall  134  of the chamber  102  when in the battery configuration  108 . During cartridge case extraction, the dynamic chamber insert  110  moves to the out-of-battery configuration  106  and expands radially to relieve pressure on the cartridge casing  82  to allow for extraction, even overcoming any quasi-interference fit that may occur between the dynamic chamber insert  110  and the fired cartridge casing  82 . 
     It will be appreciated that in certain applications, the dynamic chamber insert  110  may not fit tightly within the chamber  102 , leaving a radial gap to the inner wall  130  (similar to a radial gap  246  shown in  FIGS. 7-8 ) and/or an axial gap in front of the distal end  126 . These gaps allow the chamber insert  110  to release the case  82  without the dynamic chamber insert  110  being entirely removed from the chamber  102 . In these embodiments, the dynamic chamber insert  110  is secured in battery by contact between the angled waist  140  and proximal angled wall  136  and/or the angled fore end  142  and distal angled wall  138 , with no contact being made between the foot portion  132  and body portion  134  of the chamber  102  and the corresponding portions of the outer diameter of the dynamic chamber insert  110 . In these embodiments, in order to release the case  82 , the dynamic chamber insert  110  need only move and expand enough to release the case, and may maintain contact with some portions of the angled waist  140  and proximal angled wall  136  and/or the angled fore end  142  and distal angled wall  138  throughout the cycle between in battery and out of battery configurations  106 ,  108 . In other words, the movement between in battery and out of battery configurations of the dynamic chamber insert  110  may consist of the dynamic chamber insert  110  sliding in and out along the angled waist  140  and proximal angled wall  136  and/or the angled fore end  142  and distal angled wall  138 . In certain embodiments, the dynamic chamber insert  110  may make contact with the foot portion  132  and/or body portion  134  of chamber  102  when in the out of battery position, such contact defining the end of the out of battery movement of the dynamic chamber insert  110 . Moreover, the dynamic chamber insert  110  may not tightly retain the cartridge case  82  when initially in battery and before firing, instead providing some degree of radial clearance similar to conventional chambers. 
     Referring to  FIGS. 5-8 , an adaptable chamber insert  210  is shown in a given chamber  202  of a gun barrel  204  while accommodating a first cartridge ( FIG. 7 ) or a second cartridge ( FIG. 8 ). In certain embodiments, the first and second cartridges (not shown) are of a same caliber but have at least some dimensional variation. As shown in  FIGS. 5-6 , the adaptable chamber insert  210  may be structurally similar to the dynamic chamber insert  110 , including a wall portion  212  that defines a plurality of slits  214 . The plurality of slits  214  extend in an axial direction parallel to a bore axis  218  of the gun barrel  204 . In certain embodiments, the adaptable chamber insert  210  may be sized to surround a substantial entirety of the cartridge case  82  or extend along only a portion of the body  82  of the cartridge case  82 . The adaptable chamber insert  210  includes at least one web  222  at an axial end from which the plurality of slits  214  extend, which web  222  may be disposed at a proximal end  224  of the adaptable chamber insert  210 , a distal end  226  of the adaptable chamber insert  210 , or both proximal and distal ends  224 ,  226 . In embodiments with one web  222 , the slits  214  may extend to the opposite end of the insert  210  (e.g., from the proximal end  224  to the distal end  226 ), such that the opposite end of the insert  210  is open, in other words, with no interconnecting web. The adaptable chamber insert  210  may be an integrally formed unitary component such as the dynamic chamber insert  110  shown in  FIGS. 5-6 . As best shown in  FIGS. 5-6 , the adaptable insert is divided into segments  228 , for example six segments  228  of equal size, spread about the circumference of the adaptable insert  210 . The adaptable chamber insert  210  has an axial length L 1 , whereas the slits  214  extend for a relatively shorter axial length L 2  that may be from about 80% to about 99% of the length L 1  of the adaptable chamber insert  210 , and in certain embodiments may be about 95% of the length L 1 . In this manner, the adaptable chamber insert  210  is unitary as a continuous serpentine cord of material. 
     The adaptable chamber insert  210  is sized to closely fit within the chamber  202  of the gun barrel assembly  200 . The chamber  202  has an inner wall  230  defining a foot portion  232  and a body portion  234  connected by a proximal angled wall  236 . A distal angled wall  238  connects the body portion  234  of the chamber to the barrel  204 . Correspondingly, the adaptable chamber insert  210  extends axially along the inner wall  230  and includes an angled waist  240  for interfacing with the proximal angled wall  236  and an angled fore end  242  for interfacing with the distal angled wall  238 . By interfacing with one or more of the proximal angled wall  236  and the distal angled wall  238  in this manner, the adaptable chamber insert  210  has freedom to radially expand when moved in an axially rear direction A R  and is forced to radially contract when moved in an axially forward direction A F  (e.g., when loading a cartridge and moving to the battery configuration). Depending on the particular dimensions of the embodiment and selected cartridge  80 , the distal end  226  may not be able to be inserted as far in the forward direction A F , as shown in  FIGS. 7-8 . In other words, when the adaptable chamber insert is secured around the larger of the cartridges that it is configured to accept, the distal end  226  may not be able to be inserted as far in in the forward direction A F , as shown in  FIGS. 7-8 . The slits  214  define a variable expansion gap  244  between portions of the wall portion  212 . In some embodiments, the foot portion  232  of the chamber  202  may have various guiding or retention features to engage with the adaptable chamber insert  210  (or a complementary structure thereon) to prevent accidental back-out of the adaptable chamber insert  210 ; such structures may be a catch, complementary indent-detent, slot, or the like. 
     Notably, as shown in  FIGS. 7-8  the adaptable chamber insert  210  provides a radial gap  246  between the wall portion  212  and the inner wall  230  of the chamber  202 . The radial gap  246  may exist even when the angled waist  240  and the angled fore end  242  are respectively engaged with the proximal and distal angled walls  236 ,  238 . The radial gap  246  allows for the adaptable chamber insert  210  to adapt in size, including varying an outer diameter  248 , to hold various cartridges of varying dimensions and to release the largest size case  82  that it is configured for without needing to withdraw the adaptable chamber insert  210  entirely from the chamber  202 . In these embodiments, the adaptable chamber insert  210  is secured in battery by contact between the angled waist  240  and angled fore end  242  are respectively engaged with the proximal and distal angled walls  236 ,  238 , with no contact being made between the wall portion  212  and the inner wall  230  of the chamber  202 . In these embodiments, in order to release the case  82  or expand to accept a larger case, the adaptable chamber insert  210  need only move and expand enough to release the case and/or accept a new case, and may maintain contact with some portions of the angled waist  240  and angled fore end  242  and respective proximal and distal angled walls  236 ,  238  throughout the cycle between in battery and out of battery configurations. In other words, the movement between in battery and out of battery configurations of the adaptable chamber insert  210  may consist of the adaptable chamber insert  210  sliding in and out along the angled waist  240  and angled fore end  242  and respective proximal and distal angled walls  236 ,  238 . In certain embodiments, the wall portion  212  may make contact with the inner wall  230  of the chamber  202  when in the out of battery position, such contact defining the end of the out of battery movement of the adaptable chamber insert  210 . Moreover, the adaptable chamber insert  210  may not tightly retain the cartridge case  82  when initially in battery and before firing, instead providing some degree of radial clearance between the adaptable chamber insert  210  and the case  82 , similar to conventional chambers, which may be achieved by indexing the adaptable chamber insert  210  along the angled waist  240  and angled fore end  242  and respective proximal and distal angled walls  236 ,  238  to respective different chamber positions for respective different size cartridges by controlling the movement of the adaptable chamber insert  210  in the axial direction A F . In certain embodiments, the cartridges are of a same caliber but have one or more other dimensions varied, for example the dimensions of the case, for example diameter and length of the case. 
     The adaptable chamber insert  210  is resiliently biased toward a rest position with an inner diameter  250  that is greater than the cartridge  80  caliber, resulting in ready release of the cartridge  80  once the dynamic chamber insert  210  moves axially in rearward direction A R . The axial movement and resulting radial contraction and expansion of the adaptable chamber insert  210  may be driven, for example, by the action of the bolt (not shown). Therefore, the adaptable chamber insert  210  automatically expands radially during extraction of the cartridge case  82 . When the cartridge  80  is loaded before firing, the adaptable chamber insert  210  contracts radially to the dimension of the cartridge  80  and firmly holds the cartridge case  82 . As noted above, the adaptable chamber insert  210  may contract radially when inserted into the chamber  202  in the forward axial direction A F . The adaptable chamber insert  210  includes an inner wall  252  generally shaped to correspond to the cartridge  80 , including a body portion  254 . In embodiments for .22 caliber cartridges, the inner wall  252  may have a consistent diameter and cylindrical shape, omitting the neck portion and angled surface shown in  FIGS. 3-4 . 
     In one example for the adaptable dynamic chamber insert  210 , the first cartridge  80 LR is a .22 long rifle (“22 LR”) cartridge as shown in  FIGS. 9-10  and the second cartridge is a .22 caliber super (“22 Super”) cartridge as shown in  FIGS. 11-12 . The 22 LR has various standardized dimensions including, for example, a body diameter D B  of 0.227 inches and a headspace H in a range of 0.043-0.051 in. The body diameter D B  corresponds to a casing diameter D C  of the cartridge  80 LR. Moreover, as shown in  FIG. 10 , a corresponding chamber  202 LR for a 22 LR has standardized dimensions including a chamber length L C  of 0.818 in. 
     By contrast, a chamber  202 S for a 22 Super cartridge provides a body diameter D B  of 0.243 in. (i.e., 0.016 in. larger than the 22 LR cartridge) along with a headspace H of 0.0495-0.0505 in. and a chamber length L C  of 0.7550 in. The adaptable insert  210  of certain embodiments provides a length L 1  ( FIG. 5 ) and headspace H ( FIGS. 7-8 ) that may be substantially equal to the chamber length L C  and headspace H of the standard 22 LR of  FIGS. 9-10 , i.e., respectively 0.818 in., and 0.043-0.051 in. Due to its expandable arrangement, the adaptable insert  210  can accommodate, securely hold, fire, and eject cartridges of either the 22 LR or the 22 Super design. One skilled in the art will appreciate that an adaptable insert  210  applicable to the present disclosure may be implemented for a variety of groups of cartridges of similar sizes, such as various cartridges of a given caliber. Accordingly, the following Table 1 provides example cartridge arrangements for a range of .22 caliber options that may be applicable to the present disclosure by being accommodated within the adaptable chamber insert  210 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Selected Dimensions of .22 
               
               
                 Caliber Cartridges and Chambers 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Body  
                   
                 Chamber 
               
               
                   
                   
                 Diameter 
                 Headspace  
                 Length  
               
               
                   
                 Name 
                 D B  (in.) 
                 H (in.) 
                 L C  (in.) 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 22 LR 
                 0.227 
                 0.043-0.051 
                 0.818 
               
               
                   
                 22 Super 
                 0.243 
                 0.0495-0.0505 
                 0.7550 
               
               
                   
                 22 Short 
                 0.227 
                 0.043-0.051 
                 0.474 
               
               
                   
                 22 Long 
                 0.226 
                 0.043-0.051 
                 0.818 
               
               
                   
                 22 
                 0.2435 
                 0.050-0.056 
                 0.980 
               
               
                   
                 Winchester 
                   
                   
                   
               
               
                   
                 Magnum 
                   
                   
                   
               
               
                   
                 22 
                 0.2435 
                 0.050-0.056 
                 0.980 
               
               
                   
                 Winchester 
                   
                   
                   
               
               
                   
                 Rimfire 
               
               
                   
                   
               
            
           
         
       
     
       FIGS. 7 and 8  approximate the arrangement of the adaptable chamber insert  210  for 22 LR cartridge and a 22 Super cartridge. Due to the smaller diameter of the 22 LR cartridge, the radial gap  246  between the adaptable dynamic insert  210  and the inner wall  212  of the chamber  202  is larger with the 22 LR cartridge ( FIG. 7 ) than the corresponding radial gap  246  with the 22 Super cartridge ( FIG. 8 ). The use of an adaptable chamber insert  210  allows this variety of cartridges to be readily fired from the same firearm without rupture of the cartridge case during firing, including the same gun barrel assembly  200 , gun barrel  204 , chamber  202 , and adaptable chamber insert  210 . Moreover, the chamber  202  of this example may have a larger diameter  260  than the chamber diameter  160  illustrated in  FIGS. 3-4  for the dynamic chamber insert  110  for a barrel of the same caliber. In some embodiments and certain cartridge applications, the radial gap  246  may be effectively eliminated (e.g., a gap of about 0 in.) with a close fit within the inner wall  212  of the chamber  202 , for example when the adjustable chamber insert is configured to receive the largest cartridge that it is designed to accommodate. Likewise, the variable expansion gap  244  may be effectively eliminated (e.g., a gap of about 0 in.) in some embodiments. 
     Various modifications to the above examples are contemplated to be within the scope of the present disclosure. The various angled surfaces of the chamber, chamber inserts, and cartridges are illustrated as about 45 degree angles relative to the gun barrel axis, although other angles are contemplated including from about 15 degrees to 75 degrees and from about 30 degrees to about 60 degrees. Certain embodiments herein are specifically addressed to projectiles from .17 caliber to .50 caliber. In some embodiments, the cartridge has a .17 caliber, .223 caliber, or 5.56 NATO projectile. In other embodiments, the cartridge has a .22 caliber projectile. In embodiments, cartridges may have a lead-free, lead, or jacketed bullet. The present disclosure may also be applicable to centerfire as well as rimfire cartridges, as well as various types of firearms including handguns, rifles, semiautomatics, automatics, combinations thereof, and the like. Applicable rifles may include match, sporting, and shotgun styles. 
     In certain embodiments, one of ordinary skill in the art will appreciate that the inserts  110 ,  210  may be actuated by a bolt that pushes the insert  110 ,  210  forward in the in the axial direction A F  when chambering a cartridge  80 . After firing, the insert  110 ,  210  may reverse direction and move out of battery when the bolt reverses in the in the axial direction A F , for example simply by the pressure of the bolt on the insert  110 ,  210  being removed, or by some mechanical connection to the bolt or bolt carrier, or by a separate mechanical action initiated by the user. An extractor associated with the bolt or bolt carrier may engage with the case  82  as the bolt is being extracted, and at least initially, any friction between the case  82  and the insert  110 ,  210  may assist the insert  110 ,  210  in its initial out of battery motion. The chamber  102 ,  202  may include a mechanical stop to limit the insert&#39;s  110 ,  210  out of battery motion while the bolt travels further in the axial direction A F  in order for the bolt and extractor to eject the spent case  82  and/or chamber a new cartridge  80 . 
     In some embodiments of either the dynamic chamber insert  110  or adaptable chamber insert  210 , the slits  114 ,  214  may include a pliable filler or sheet of material to occupy the space of the variable expansion gap  144 ,  244  while preventing any buildup of residue or debris that results from firing of cartridges, or from other dirt and debris infiltrating the chamber. In certain embodiments, this filler may include a thermoplastic elastomer, rubber, fabric, non-woven material, or other such material. In certain embodiments, the insert  110 ,  210  may be provided with fewer or greater than the disclosed six segments and slits, such as one slit and one segment, two, three, four, five, seven, eight, nine, ten, eleven, or twelve. In one embodiment that includes one slit, the one slit may traverse a partial length of the insert  110 ,  210  and terminating at a web, or it may traverse the entire length of the insert  110 ,  210  such that there is no web and the insert  110 ,  210  is akin to “C” shape in profile. Moreover, the principles of the invention may be embodied in other embodiments including structures that similarly provide a radially-outward bias for cartridge case extraction and can be selectively engaged with a cartridge while inserted into a firearm chamber. The inserts may be a sleeve-like constant-force spring such as a sheet of resilient metal wrapped once over itself, or wrapped less or more than once over itself, with the amount of overlap varying the diameter of the insert. In such embodiments, the chamber contracts when the coil of the spring is tightened, and the chamber expands when the tension on the spring is released. In other embodiments, inserts may be provided as a helical insert made from e.g. coiled wire, also known as a screw thread insert or STI. In such embodiments, the spring undergoes a twisting motion to tighten about the cartridge or a reversed twisting motion to loosen when in the out-of-battery configuration. 
     All of the features disclosed, claimed, and incorporated by reference herein, and all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is an example only of a generic series of equivalent or similar features. Inventive aspects of this disclosure are not restricted to the details of the foregoing embodiments, but rather extend to any novel embodiment, or any novel combination of embodiments, of the features presented in this disclosure, and to any novel embodiment, or any novel combination of embodiments, of the steps of any method or process so disclosed. 
     Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement calculated to achieve the same purpose could be substituted for the specific examples disclosed. This application is intended to cover adaptations or variations of the present subject matter. Therefore, it is intended that the invention be defined by the attached claims and their legal equivalents, as well as the illustrative aspects. The above described embodiments are merely descriptive of its principles and are not to be considered limiting. Further modifications of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the inventive aspects.