Patent Publication Number: US-11047643-B2

Title: Ballistic chain cutting device

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 16/218,213, filed Dec. 12, 2018, and the foregoing related application, in its entirety, is hereby incorporated herein by reference. 
    
    
     FEDERALLY SPONSORED RESEARCH 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to devices for gaining forcible entry into locked premises and structures. More specifically, the invention is an improved ballistic chain cutting device that mounts on the barrel of a firearm and holds a target link from multi-link chain in the proper position for a projectile fired from the firearm to cut an opening in the target link. 
     2. Description of the Related Art 
     Military personnel and law enforcement officers often encounter situations where they need to gain access into premises or structures locked with a chain comprising multiple interconnected metal links (“multi-link chain”). In many of these situations, criminals, enemy combatants, or other wrongdoers are within the chain-locked premises or structures, and time is of the essence to rapidly gain access. Any time lost through cumbersome forcible entry methods allows additional time for those inside to prepare and defend against such entry, and can literally be the difference between life and death. 
     There are a variety of ways by which the military personnel and law enforcement personnel can gain access when presented with a chain-locked premise or structure. Ballistic opening of the multi-link chain is one way to rapidly gain access, but requires precision shot placement to properly open the target link. More specifically, the firearm must be aimed at the target link with enough accuracy to ensure the projectile creates an opening in the target link large enough for a link adjacent to the target link (“adjacent link”) to pass through the opening. If the first shot does not open the target link enough, multiple shots may be required. However, the first shot alerts those inside that forcible entry is being attempted and multiple shots gives them additional time to prepare and defend against the entry. Thus, reducing the number of shots required to open the target link is an important objective. 
     Additionally, the shot to open the target link is usually in close quarters with the multi-link chain and the person firing the shot is presented with increased danger from the potential ricochet of the projectile. The risk of ricochet-induced injury increases as more shots are fired. Thus, ensuring the projectile is accurately placed on the target link with the first shot helps reduce this risk. 
     U.S. Pat. No. 9,372,048 (“Prior Patent”), which Applicant developed and owns, discloses a Ballistic System and Method for Cutting a Multi-Link Metal Chain. The Prior Patent is the subject of Reissue Patent application Ser. No. 16/013,458 (“Reissue Application”) and as of the filing date of this Divisional Application the Prior Patent has re-issued as Reissue Patent No RE47,850. Both U.S. Pat. No. 9,372,048 and Reissue Patent application Ser. No. 16/013,458 are incorporated herein by reference in their entirety. 
     Applicant&#39;s Prior patent and the Reissue application disclose a system and method to properly position the target link of a multi-link chain for ballistic opening or “cutting” of the target link with a single projectile (i.e., with a single “shot”). The present application is directed to improvements of the system and apparatus disclosed in the Prior patent and the Reissue application. 
     BRIEF SUMMARY 
     The present invention is an Improved Ballistic Chain Cutting Device. It contains improvements over the Prior patent and the Reissue application to better secure the target link and the adjacent link within the device. The improvements help ensure the projectile is properly placed on the target link and that the target link opens with the first shot. The improvements generally comprise an embodiment with a stepped slot between a first target link pin and a second target link pin to better accommodate differing chain sizes, an embodiment with the slot extending below a planar surface on a base member of the device, an embodiment with curved adjacent link engagement regions to better accommodate differing chain sizes, an embodiment with a curved target link engagement surface, and variations or combinations of the aforementioned embodiments. Additionally, further improvements will become apparent in the detailed description of certain embodiments infra. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an embodiment of the present invention and a firearm barrel, from a distal end of the embodiment. 
         FIG. 2  is a perspective view of the embodiment shown in  FIG. 1 , from a proximal end of the embodiment. 
         FIG. 3  is a plan view of the proximal end of the embodiment shown in  FIG. 1 . 
         FIG. 4  is a side view of the embodiment shown in  FIG. 1 . 
         FIG. 5  is a perspective view of the embodiment shown in  FIG. 1 , from the distal end of the embodiment at an angle different than that shown in  FIG. 1 . 
         FIG. 6  is a side view of the embodiment shown in  FIG. 1 . 
         FIG. 7  is a side cross-sectional view of the embodiment shown in  FIG. 1 , taken along section line  7 - 7  in  FIG. 6 . 
         FIG. 8  is a side cross-sectional view of the embodiment shown in  FIG. 1 , taken along section line  8 - 8  in  FIG. 4 . 
         FIG. 9  is a plan view of the distal end of the embodiment shown in  FIG. 1 . 
         FIG. 10  is blown-up cross sectional view of embodiment shown in  FIG. 1 , taken along section line  5 - 5  in  FIG. 5 . 
         FIG. 11A  is a side cross-sectional view of the embodiment shown in  FIG. 1 , taken along section line  7 - 7  in  FIG. 6 , with a large-sized multi-link chain shown in phantom. 
         FIG. 11B  is a side cross-sectional view of the embodiment shown in  FIG. 1 , taken along section line  7 - 7  in  FIG. 6 , with a medium-sized multi-link chain shown in phantom. 
         FIG. 11C  is a side cross-sectional view of the embodiment shown in  FIG. 1 , taken along section line  7 - 7  in  FIG. 6 , with a small-sized multi-link chain shown in phantom. 
         FIG. 12  is a perspective view showing a second embodiment of the present invention and a firearm barrel, from a proximal end of the embodiment. 
         FIG. 13  is a side cross-sectional view of the embodiment shown in  FIG. 12 , taken along section line  13 - 13  in  FIG. 12 . 
         FIG. 14  is a perspective view showing a third embodiment of the present invention and a firearm barrel, from a proximal end of the embodiment. 
         FIG. 15  is a side cross-sectional view of the embodiment shown in  FIG. 14 , taken along section line  15 - 15  in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
       FIG. 1  shows an embodiment  10  that includes a base member  12  having a distal end  14  and a proximal end  16 . In operation, the proximal end  16  of the base member  12  faces toward a firearm barrel  18  and the distal end  14  faces away from the firearm barrel  18 . 
     A first target link pin  20 , a second target link pin  22 , and an adjacent link pin  24  extend from the distal end  14  of the base member  12 . Preferably, the distal end  14  has a planar surface  26  from which the first target link pin  20 , the second target link pin  22 , and the adjacent link pin  24  extend. Additionally, the base member  12  has exterior side surfaces intersecting the planar surface  26 , which may alternate between planar and curved. For example,  FIG. 1  shows a planar side surface  30  along the front of the embodiment  10  and a curved side surface  32  along the top of the embodiment  10 . Additionally, a beveled edge  34  may be placed at the intersection between the planar surface  26  and one or more of the side surfaces. 
     Referring to  FIGS. 1, 2 , &amp;  3 , a barrel-receiving portion  36  extends from the proximal end  16  of the base member  12 . The barrel-receiving portion  36  generally comprises at least one wall with an interior surface defining a substantially cylindrical volume. The barrel-receiving portion  36  can take many forms, depending on the embodiment. For example, the barrel-receiving portion  36  in the embodiment  10  comprises a wall  38  with a generally uniform interior surface  42  that forms a substantially cylindrical volume  40  and a non-uniform exterior surface  44 . Concerning the latter, the exterior surface  44  has a generally cylindrical profile, but the circumference around the cylindrical profile varies greatly due to features on the exterior. 
     As best shown in  FIG. 4 , the features on the exterior surface  44  includes a tapered surface  46  where the circumference of the generally cylindrical profile decreases from the base member  12 , a transition surface  48 , a flange  50 , and a barrel entry  52 . Additionally, the planar side surface  30  of the base member  12  continues into the barrel-receiving portion  36  so as to be adjacent the tapered surface  46 , while a beveled edge  54  is positioned between the curved side surface  32  of the base member  12  and the tapered surface  46 . 
       FIG. 4  also shows an obround cutout  56  that includes a breakaway aperture  58  on the first target link pin  20  adjacent the base member  12 . Although not shown, the embodiment  10  is symmetric and has a similarly shaped and positioned cutout and breakaway aperture on the second target link pin  22 . The cutout  56  is an area where material has been removed from a target link pin. When present, the cutout  56  and the breakaway aperture  58  encourage the first target link pin  20  and the second target link pin  22  to break apart from the base member  12  when the embodiment  10  is used and a shot is fired, thereby making the embodiment  10  a single-use device. 
     Referring to  FIGS. 1-4 , the barrel entry portion  52  comprises a plurality of fingers  64  separated by expansion gaps  66 . Each of the fingers  64  has a beveled edge  68  leading into an interior groove  70  that accepts a flange  72  on the exterior of the firearm barrel  18  and the expansion gaps  66  allow the fingers  64  to flex radially outward when the embodiment  10  is inserted onto the firearm barrel  18  over the flange  18 . Each of the expansion gaps  66  extends into a vent aperture  74  that extends between the interior surface  42  and the exterior surface  44  of the barrel-receiving portion  36  at the barrel entry  52 . Additional vent apertures  76  extending between the interior surface  42  and the exterior surface  44  are also present in the embodiment  10 . These additional vent apertures  76  exit the exterior surface  44  at the intersection of the tapered surface  46  and transition surface  48 . 
     The exact configuration of the barrel entry  52  and the shape of the substantially cylindrical volume  40  depend on the design of the firearm barrel  18  used with the device. In practice, the interior surface  42  preferably contains one or more features that allow the device to be fixed on the firearm barrel  18  so the device does not fall off the barrel  18  due to gravity when the barrel  18  is pointed or aimed in a downward direction. For example, the illustrated embodiment  10  is designed to fit onto a Surefire® flash suppressor Model Number SFMB-556-1/2-28 and the interior groove  70  on the interior surface  42  of each of the fingers  64  accepts the flange  72 , as discussed above. However, alternative embodiments contain different features which allow the device to be fixed onto other types of firearm barrels or other components (e.g., compensators, flash suppressors, silencers, etc.) attached to the muzzle end of a firearm barrel. 
     Additionally, the wall  38  may have other features designed to correlate with the type of firearm barrel  18  on which the device is mounted. For example, the vent apertures  74 ,  76  are alignable with vents  78  on the firearm barrel  18  so that the vents  78  can properly expel gas when the projectile is fired. More specifically, the embodiment  10  contains a total of four vent apertures  74  and four additional vent apertures  76  at ninety degree intervals around the substantially cylindrical volume  40 , making a total of eight vent apertures  74 ,  76 . The embodiment  10  can be rotated on the firearm barrel  18  about a center axis x to align some of the vent apertures  74 ,  76  with the vents  78  on the barrel  18 . While the illustrated firearm barrel  18  only requires a total of four vent apertures to align with its vents  78 , the extra vent apertures on the embodiment  10  reduce the amount of time and rotation required for alignment to be obtained. In particular, the embodiment  10  requires, at most, a ninety degree rotation about the center axis x before four of the vent apertures  74 ,  76  become properly aligned with the vents  78 . However, in alternative embodiments, more or less vent apertures  74 ,  76  may be present or even no vent apertures  74 ,  76  at all. 
       FIGS. 2 &amp; 3  also show a projectile aperture  80  at the proximal end  16  of the base member  12 . The projectile aperture  80  is defined by a sidewall  82  extending through the base member  12 , between its proximal end  16  and its distal end (not shown). The projectile aperture  80  is centered on the center axis x, with center axis x also being the center of the substantially cylindrical volume  40 . Preferably, but not necessarily, the sidewall  82  defines a substantially cylindrical projectile aperture  80 . 
       FIG. 5  shows the projectile aperture  80  and the center axis x at the distal end  14  of the base member  12 , with the aperture  80  opening into the planar surface  26  in the center of the embodiment  10 . Two of the fingers  64  and one of the expansion gaps  66  can be seen through the projectile aperture  80 , and the aperture  80  should be large enough for a projectile (not shown) exiting the firearm barrel  18  to pass through the aperture  80  without contacting the sidewall  82 . 
       FIG. 5  also illustrates the preferred orientation of the first target link pin  20 , the second target link pin  22 , and the adjacent link pin  24  extending from the distal end  14  of the base member  12 . In the embodiment  10 , these elements extend from the planar surface  26 ; however in alternative embodiments the planar surface  26  may not be present such as, for example, if the surface  26  were not planar. Also shown are the alternating planar side surfaces  30  and curved side surfaces  32  on the exterior sides of the base member  12 , which may be shaped or configured differently in alternative embodiments. 
       FIG. 5  also illustrates a slot  90  between a first pin target link alignment region  92  on the first target link pin  20  and a second pin target link alignment region  94  on the second target link pin  22 . The first pin target link alignment region  92  and the second pin target link alignment region  94  are the areas of, respectively, the first target link pin  20  and the second target link pin  22  between which a target link of a multi-link chain (not shown) is positioned during use of the device. As such, the slot  90  has a first sidewall  96  at least partially defined by the first pin target link alignment region  92  and a second sidewall  98  at least partially defined the second pin target link alignment region  94 , as shown in  FIG. 6 . 
     As shown in  FIGS. 5 &amp; 6 , the first and second sidewalls  96 ,  98  preferably extend through the planar surface  26  into the base member  12  and come together to form a bottom  100  of the slot  90 . In the embodiment  10 , the slot  90  extends into one of the curved side surfaces  32  of the base member  12 . The sidewalls  96 ,  98  define a width w of the slot  90 , which varies in the illustrated embodiment  10 . For example, the sidewalls  96 ,  98  in the embodiment  10  have one or more pairs of corresponding steps where the width w increases, as the sidewalls  96 ,  98  extend further away from the bottom  100 . More specifically, the width w increases at a first pair of corresponding steps  102  positioned adjacent the planar surface  26  of the base member  12 , followed by a width w increase at a second pair of corresponding steps  104 . 
       FIG. 7  shows the second pin target link alignment region  94  of the second pin  22 . The second pin target link alignment region  94  is a mirror image of the first pin target link alignment region  92  (not shown) because the embodiment  10  is symmetric about the mid-plane at section line  7 - 7  in  FIG. 6 . Thus, if a first plane were extended between each step in the first pair of corresponding steps  102  and a second plane were extended between each step in the second pair of corresponding steps  104 , both planes would be parallel to the planar surface  26  at the distal end  14  of the base member  12 . In the embodiment  10 , the planar surface  26  is orthogonal to the center axis x and, thus, each of the pairs of corresponding steps  102 ,  104  in the embodiment  10  is oriented substantially orthogonal to the center axis x. 
     Preferably, the first pin and second pin target link alignment regions  92 ,  94  each have at least one planar surface substantially parallel to each other. For example,  FIG. 7  shows the embodiment  10  has a first planar surface  110  and a second planar surface  112  on the second pin target link alignment region  94 , with each planar surface  110 ,  112  separated by a bore wall  114  that contains the breakaway aperture  58 . Referring to  FIG. 8 , the first planar surface  110  is substantially parallel to a first planar surface  116  on the first pin target link alignment region  92  and forms a width w 1 , while the second planar surface  112  is substantially parallel to a second planar surface  118  on the first pin target link alignment region  92  and forms a width w 2 . Additionally, each of the planar surfaces  110 ,  112 ,  116 ,  118  in the embodiment  10  is oriented substantially orthogonal to the planar surface  26  of the distal end  14  because they would form a ninety-degree angle with the planar surface  26  if they intersected it. 
     Referring back to  FIG. 5 , the first target link pin  20  has a first pin adjacent link engagement region  130  and the second target link pin  22  has a second pin adjacent link engagement region  132 . As will be seen, the first pin and second pin adjacent link engagement regions  130 ,  132  are areas where a link adjacent to the target link (the “adjacent link”) rests against, or engages, when the target link is placed in the slot  90  for operation of the device. In the embodiment  10 , the first pin and second pin adjacent link engagement regions  130 ,  132  each contain at least one curved surface for a semicircular end of the adjacent link to nest within. More specifically, the curved surface on the first pin adjacent link engagement region  130  and the curved surface on second pin adjacent link engagement region  132  are aligned to define part of a circumference of a circle having a radius equal to the radius of the outer circumference of the semicircular end of the adjacent link. 
     In the illustrated embodiment  10 , three distinct curved surfaces on the first pin adjacent link engagement region  130  align with three distinct curved surfaces on the second pin adjacent link engagement region  132 . Referring to  FIG. 8 , the first pin adjacent link engagement region  130  has a primary curved surface  150 , a secondary curved surface  154 , and tertiary curved surface  158  that each align with, respectively, a primary curved surface  162 , a secondary curved surface  166 , and tertiary curved surface  170  of the second pin adjacent link engagement region  132 . Preferably, but not necessarily, the primary curved surfaces  150 ,  162  intersect with the planar surface  26 . 
     As shown in  FIG. 10 , the intersection between the primary curved surface  162  of the second pin adjacent link engagement region  132  forms an angle θ between the primary curved surface  162  and the planar surface  26 , with angle θ being greater than ninety degrees. Although not shown in  FIG. 10 , an angle equal to angle θ is also formed at the intersection of the primary curved surface  150  of the first pin adjacent link engagement region  130  due to the symmetry of the embodiment  10   
     Referring back to  FIG. 8 , the illustrated embodiment  10  has steps separating the various curved surfaces, thereby creating pairs of corresponding steps between the first pin adjacent link engagement region  130  and the second pin adjacent link engagement region  132 . In particular, there is a first pair of corresponding steps  174  separating the primary curved surfaces  150 ,  162  and the secondary curved surfaces  154 ,  166 , as well as a second pair of corresponding steps  176  separating the secondary curved surfaces  154 ,  166  and the tertiary curved surfaces  158 ,  170 . At each of the pairs of corresponding steps  174 ,  176  the partial circumference defined by the curved surfaces expands. 
     As shown in  FIG. 9 , the three distinct curved surfaces on the first and second pin adjacent link engagement regions  130 ,  132  are aligned to form the partial circumference of three distinct circles having three distinct centers. In particular, the primary curved surfaces  150 ,  162  are aligned to form a partial circumference of Circle  1  having center C 1 , the secondary curved surfaces  154 ,  166  are aligned to form a partial circumference of Circle  2  having center C 2 , and the tertiary curved surfaces  158 ,  170  are aligned to form a partial circumference of Circle  3  having center C 3 , and none of the circle centers C 1 , C 2 , or C 3  is coaxial with the center axis x of the projectile aperture  80 . As shown, Circle  1  is smaller than Circle  2  and Circle  2  is smaller than Circle  3 , and the partial circumference formed by the primary curved surfaces  150 ,  162  is smaller than the partial circumference formed by the secondary curved surfaces  154 ,  166 , and the partial circumference formed by the secondary curved surfaces  154 ,  166  is smaller than the partial circumference formed by the tertiary curved surfaces  158 ,  170 . 
     With three differently sized partial circumferences being formed by the three sets of aligned curved surfaces, three different sizes of multi-link chains are accommodated in the embodiment  10 . More specifically, Circle  1  has a radius R 1  equal to the radius of the outer circumference of the semicircular end of a small-sized adjacent link, Circle  2  has a radius R 2  equal to the radius of the outer circumference of the semicircular end of a medium-sized adjacent link, and Circle  3  has a radius R 3  equal to the radius of the outer circumference of the semicircular end of a large-sized adjacent link. For example, a ¼″ chain may nest within the partial circumference defined by the primary curved surfaces  150 ,  162 , a 5/16″ chain may nest within the partial circumference defined by the secondary curved surfaces  154 ,  166 , and a ⅜″ chain may nest within the partial circumference defined by the tertiary curved surfaces  158 ,  170 . 
     It should be noted, however, that in alternative embodiments the curved surface on the first pin adjacent link engagement region  130  and the curved surface on the second pin adjacent link engagement region  132  may be configured differently or may not be curved. Additionally, there may be more or less pairs of corresponding steps between the first pin adjacent link engagement region  130  and the second pin adjacent link engagement region  132 , or no steps at all. 
       FIG. 9  also shows a bore  180  that is preferably between the first and second target link pins  20 ,  22 . The bore  180  extends through the first and second pairs of corresponding steps  102 ,  104  on the first pin and second pin target link alignment regions  92 ,  94 . As best shown in  FIG. 7 , the bore wall  114  extends along the second pin target alignment region  94  with the bore  180  being not quite perpendicular to the planar surface  26 . The bore  180  terminates a bottom end  182  further within the base member  12  than the bottom  100  of the slot  90 . The bore wall  114  extends along the first pin target link alignment region  92  in a similar manner due to the symmetry of the embodiment  10 . When present, the bore  180  provides additional space for a chain weld on the target link to fit within. 
     Referring back to  FIG. 6 , the adjacent link pin  24  can be seen though the slot  90 . The adjacent link pin  24  preferably has a curved surface  184  that narrows as it approaches the planar surface  26 . The curved surface  184  in the embodiment  10  also extends from the adjacent link pin  24  into the base member  12 , slightly below the planar surface  26 .  FIG. 7  shows part of the curved surface  184  on the adjacent link pin  24 , as well as an angled back surface  186  opposite the curved surface  184 . The angled back surface  186  extends from a generally vertical back surface  188 , with the generally vertical back surface  188  intersecting the planar surface  26  of the distal end  14  at a substantially perpendicular angle. Preferably, the angled back surface  186  is oriented at an acute angle with respect to the center axis x. As shown, if the angled back surface  186  was extended, it would intersect the center axis x at an acute angle α. 
       FIGS. 11A-11C  illustrate a cross section of the embodiment  10  in use with a multi-link chain of different sizes. In  FIG. 11A , a small-sized chain  200  is shown, with a target link  204  and an adjacent link  206 . The target link  204  fits within the slot  90  such that a portion of the target link  204  rests against the bottom  100  of the slot  90 . The portion that rests against the bottom  100  of the slot  90  also fits tightly within the portion of the slot sidewall  98  between the bottom  100  and the planar surface  26  and the corresponding portion of the slot sidewall  96  between the bottom  100  and the planar surface  26  (not shown) at width w 1  in  FIG. 8 . A chain weld  208  on the target link  204  is within the bore  180  and a semicircular end  210  of the target link  204  is engaged with the curved surface  184  of the adjacent link pin  24  close to the projectile aperture  80 , with a portion of the target link  204  within the aperture  80 . The adjacent link pin  24  is inserted through the adjacent link  206  and a semicircular end  212  of the adjacent link  206  is nested within the primary curved surface  162  of second pin adjacent link engagement region  132 . 
     In  FIG. 11B , a medium-sized chain  220  is shown, with a target link  224  and an adjacent link  226 . The target link  224  fits within the slot  90  such that a portion of the target link  224  rests against the first pair of corresponding steps  102 . The portion that rests against the first pair of corresponding steps  102  also fits tightly within the first planar surface  110  of the second pin target link alignment region  94  and the first planar surface  116  of the first pin target link alignment region  92  (not shown) at width w 2  in  FIG. 8 . A chain weld  228  on the target link  224  is within the bore  180  and a semicircular end  220  of the target link  224  is engaged with the curved surface  184  of the adjacent link pin  24  at a location on the curved surface  184  further away from the projectile aperture  80  than the location where the small-sized chain  200  was engaged, and none of the target link  224  is within the aperture  80 . The adjacent link pin  24  is inserted through the adjacent link  226  and a semicircular end  232  of the adjacent link  226  is nested within the secondary curved surface  166  of second pin adjacent link engagement region  132 . 
     In  FIG. 11C , a large-sized chain  240  is shown, with a target link  244  and an adjacent link  246 . The target link  244  fits within the slot  90  such that a portion of the target link  244  rests against the second pair of corresponding steps  104 . The portion that rests against the second pair of corresponding steps  104  also fits tightly within the second planar surface  112  of the second pin target link alignment region  94  and the second planar surface  118  of the first pin target link alignment region  92  (not shown) at width w 3  in  FIG. 8 . A chain weld  248  on the target link  244  is within the bore  180  and a semicircular end  250  of the target link  244  is engaged with the curved surface  184  of the adjacent link pin  24  at a location on the curved surface  184  further away from the projectile aperture  80  than the location where the medium-sized chain  220  was engaged, and none of the target link  244  is within the aperture  80 . The adjacent link pin  24  is inserted through the adjacent link  246  and a semicircular end  252  of the adjacent link  246  is nested within the tertiary curved surface  166  of second pin adjacent link engagement region  132 . 
       FIG. 12  shows a second embodiment  300  of the device for use with a standard, military specified A 2  Birdcage firearm barrel  302 . The embodiment  300  has a barrel-receiving portion  308  with a wall  310  having a generally uniform interior surface  312  that forms a substantially cylindrical volume  314  and a non-uniform exterior surface  316 . Concerning the latter, the exterior surface  316  has a generally cylindrical profile, but the circumference around the cylindrical profile varies greatly due to features on the exterior. The features on the exterior surface  316  include a tapered surface  318 —where the circumference of the generally cylindrical profile decreases from a cylindrical base member  320 —and a skirted flange  322 , with the skirted flange  322  at least partially surrounding a continuous barrel entry  324  that does not have expansion gaps. 
       FIG. 13  illustrates the substantially cylindrical volume  314  formed by the interior surface  312  of the wall  310 . The interior surface  312  has a groove  326  disposed therein that accepts an O-ring  328 . The firearm barrel  302  has a flange  330  and a groove  332  disposed around its circumference and, during insertion, the O-ring  328  flexes radially outward until the flange  330  is between the groove  326  and a proximal end  334  of the base member  320  with a projectile aperture  336 . Then, once the flange  330  is positioned between the groove  326  and the proximal end  334 , the O-ring  328  rests within the groove  326  on the interior surface  312  and the groove  332  on the firearm barrel  302 , thereby helping to hold the embodiment  300  in place on the firearm barrel  302 . 
       FIG. 14  shows a third embodiment  400  of the device for use with a silencer  402  on a firearm barrel  404 . The embodiment  400  has a barrel-receiving portion  408  with a wall  410  having a generally uniform interior surface  412  that forms a substantially cylindrical volume  414  and a generally uniform exterior surface  416 . Concerning the latter, the exterior surface  416  has a cylindrical profile that does not vary due to features on the exterior. Rather, the exterior surface  416  is a single, continuous surface that extends from a cylindrical base member  418   
       FIG. 15  illustrates the substantially cylindrical volume  414  formed by the interior surface  412  of the wall  410 . The interior surface  412  has a groove  426  disposed therein that accepts an O-ring  428 . The silencer  402  has a flange  430  and a groove  432  disposed around its circumference and, during insertion, the O-ring  428  flexes radially outward until the flange  430  is between the groove  426  and a proximal end  434  of the base member  418  with a projectile aperture  436 . Then, once the flange  430  is positioned between the groove  426  and the proximal end  434 , the O-ring  428  rests within the groove  426  on the interior surface  412  and the groove  432  on the silencer  402 , thereby helping to hold the embodiment  400  in place on the silencer  402 . 
     The present invention may be manufactured in a variety of ways. For example, the device may be made from a hard plastic or metal (e.g., aluminum) blank inserted into a computer numerical control (CNC) machine with the appropriate machine control instructions. Alternatively, the device may be made from injection-molded plastic or made from other manufacturing methods known in the art. 
     The present invention is described in terms of specifically described embodiments. Those skilled in the art will recognize that other embodiments of such device can be used in carrying out the present invention. Other aspects and advantages of the present invention may be obtained from a study of this disclosure and the drawings, along with the appended claims.