Patent Publication Number: US-9835401-B2

Title: Methods of manufacturing a muzzle brake

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a divisional of U.S. patent application Ser. No. 14/698,383 filed Apr. 28, 2015 now U.S. Pat. No. 9,683,802), which is a continuation-in-part of U.S. patent application Ser. No. 29/512,552 filed Dec. 19, 2014 (now U.S. Pat. No. D754,275), and a continuation-in-part of U.S. patent application Ser. No. 29/515,219 filed Jan. 21, 2015 (now U.S. Pat. No. D759,188), the disclosures of all of which are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     A common problem associated with shooting firearms is the tendency for the firearm to recoil or kick as a result of rapid expansion and propulsion of gases from the firearm during and after firing. The forces and torque generated by propellant gas during firing generally push the muzzle back toward the shooter and/or upward, forcing the shooter to adjust and re-aim after every shot, thereby making it extremely difficult or impossible to engage in accurate rapid fire. Recoil can also be painful or uncomfortable for the shooter. In an automatic, simulated automatic, or semi-automatic weapon, the recoil phenomenon is compounded, as the muzzle will recoil incrementally with each shot, causing the barrel to move farther and farther (or “walk”) away from the target. 
     SUMMARY 
     In general terms, this disclosure is directed to a muzzle brake for a firearm. In one possible configuration, and by non-limiting example, the muzzle brake includes a body portion having an internal bore and a plurality of gas vents, and a plurality of projections extending outward from the body portion. 
     One aspect a muzzle brake comprising a nose at a front end of the muzzle brake, a mounting portion at a back end of the muzzle brake, a body portion between the nose and the mounting portion that tapers towards the nose, the body portion comprising an internal bore and a plurality of gas vents, and a plurality of projections, wherein each projection of the plurality of projections extends outward from the body portion. 
     Another aspect is a muzzle brake comprising a nose at a front end of the muzzle brake, the nose comprising a depressed surface interior to the muzzle brake, a mounting portion at a back end of the muzzle brake, and a body portion between the nose and the mounting portion that tapers towards the nose, the body portion comprising a substantially hollow internal bore and a plurality of gas vents, each of the plurality of gas vents being defined by a frame comprising a top frame member, a bottom frame member, and a back frame member behind the gas vent, the back frame member being angled outward from the body portion of the muzzle brake. 
     A further aspect is a method of manufacturing a muzzle brake comprising: providing a mold for a muzzle brake, wherein the mold comprises a plurality of air-powered slides and the muzzle brake comprises a nose, a mounting portion, a body portion comprising an internal bore between the nose and the mounting portion and a plurality of gas vents, each of the plurality of gas vents being defined by a frame comprising a top frame member, a bottom frame member, and a back frame member behind the gas vent, the back frame member being angled outward from the body portion of the muzzle brake, the muzzle brake further comprising a plurality of projections extending outward from the body portion; injecting liquid wax into the muzzle brake mold; allowing the liquid wax to solidify in the muzzle brake mold; retracting the air-powered slides from the muzzle brake mold to open the plurality of gas vents and create the frames; extracting the solid wax from the muzzle brake mold; coating the extracted solid wax in ceramic to create a ceramic muzzle brake mold; melting the wax out of the ceramic muzzle brake mold; and pouring molten metal into the ceramic muzzle brake mold to cast a muzzle brake. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view of an example of a muzzle brake in accordance with the present disclosure mounted on a firearm muzzle. 
         FIG. 2  is a top, front end isometric view of an example of a muzzle brake in accordance with the present disclosure. 
         FIG. 3  is a bottom, front end isometric view of the muzzle brake of  FIG. 2 . 
         FIG. 4  is top, back end isometric view of the muzzle brake of  FIG. 2 . 
         FIG. 5  is a right side view of the muzzle brake of  FIG. 2 . 
         FIG. 6  is a left side view of the muzzle brake of  FIG. 2 . 
         FIG. 7  is a top view of the muzzle brake of  FIG. 2 . 
         FIG. 8  is a cross-sectional view of the muzzle brake of  FIG. 2  along line  8 - 8  in  FIG. 7 . 
         FIG. 9  is a bottom view of the muzzle brake of  FIG. 2 . 
         FIG. 10  is a front view of the muzzle brake of  FIG. 2 . 
         FIG. 11  is a back view of the muzzle brake of  FIG. 2 . 
         FIG. 12  is a cross-sectional view of the muzzle brake of  FIG. 2  along line  12 - 12  in  FIG. 11 . 
         FIG. 13  illustrates an example method of manufacturing muzzle brakes in accordance with the present disclosure. 
         FIG. 14  illustrates an example method of manufacturing a muzzle brake model. 
         FIG. 15  illustrates an example investment casting method for making copies of a muzzle brake model. 
         FIG. 16  illustrates an example method of machining muzzle brake model copies into their final configuration for mounting on, and use with, a firearm. 
         FIG. 17  is a top, rear, left side perspective view of an alternative embodiment of a muzzle brake in accordance with the present disclosure. 
         FIG. 18  is a top view of the muzzle brake of  FIG. 17 . 
         FIG. 19  is a cross-sectional view of the muzzle brake of  FIG. 17  along line  19 - 19  in  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments are described herein in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the appended claims. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. 
       FIG. 1  is a schematic perspective view of a firearm  2 . In this example, the firearm  2  includes a receiver  6 , a barrel  8  having a muzzle end  9 , and a muzzle brake  10 . 
     In some embodiments the firearm  2  is a gun that fires a projectile, such as a bullet. The firearm  2  can be of a variety of types including at least handguns and rifles. The firearm can also have one of a variety of different types of actions, including single action, semi-automatic, fully automatic, or a combination. 
     The firearm  2  typically includes a receiver  6  that includes various mechanical components of the firearm, such as a trigger mechanism and other parts depending on the particular type and action of the firearm. 
     The barrel  8  is connected to and extends from a front end of the receiver  6 . The barrel  8  has a hollow bore through which the projectile can be fired. The barrel  8  guides the projectile toward the muzzle end  9  of the barrel where it exits the barrel  8  and begins traveling along a flight path toward its target. 
     The muzzle brake  10  is connected to and extends from the muzzle end  9  of the barrel  8 . In at least some embodiments the muzzle brake  10  operates to capture at least some of the expanding gas created during firing at the muzzle end  9  of the barrel  8  and to create turbulence and/or redirect the gas. In doing so, the muzzle brake  10  provides, in at least some embodiments, at least one of a forward and a downward force to the muzzle end  9  of the firearm  2 , which functions to counter the rearward and upward recoil forces generated in the firearm  2 . To do so, the muzzle brake  10  is typically affixed to the muzzle end  9  of the barrel  8  and aligned with the long axis of the barrel  8 . Turbulence, as well as redirecting expanding gas away from the long axis of the barrel  8  and/or towards the shooter tends to balance and neutralize axial recoil (i.e. recoil along the barrel toward the shooter), while turbulence, as well as redirecting expulsion of the gas upwards, tends to reduce the upward kick at the muzzle end  9  of the barrel  8 . 
       FIG. 2  is a top, front end isometric view of an example of a muzzle brake  10  in accordance with the present disclosure. In this example, the muzzle brake  10  includes a front end  11 , a nose portion  12 , a body portion  13 , a mounting portion  14 , a back end  15 , and an internal bore  17 . In some embodiments the body portion  13  includes an exterior surface  19  having a top surface  16  and a bottom surface  18 . 
     In this example the muzzle brake  10  includes the front end  11 , and a back end  15  opposite the front end  11 . 
     The nose portion  12  is arranged at and extends rearward from the front end  11  of the muzzle brake  10 . The nose portion  12  includes an opening formed therein through which the projectile can pass after being fired by the firearm  2 . 
     The body portion  13  extends between the nose portion  12  and the mounting portion  14 . In some embodiments the body portion  13  has a substantially tubular shape, such as having a substantially circular exterior cross-sectional shape, but for the gas vents and projections discussed below. Other embodiments have differently shaped body portions, such as having flat exterior surfaces, such as forming a square or hexagonal cross-section, or another shape. The term “substantially” includes both configurations that are precisely matching and configurations that are mostly, but not exactly, matching. For example, a substantially tubular body portion includes shapes that are entirely tubular and shapes that are mostly, but not entirely, tubular. 
     In some embodiments the body portion  13  includes an exterior surface  19  having a top surface  16 , a bottom surface  18 , and an internal bore  17 . In the illustrated example, the exterior surface  19  has a circular cross-sectional shape, such that the top and bottom surfaces  16  and  18  are curved. The internal bore  17  also has a circular cross-sectional shape defining a substantially hollow internal passageway through which the projectile (e.g., a bullet) can pass upon firing of the firearm  2 , such as shown in  FIG. 1 , to which the muzzle brake  10  is mounted. Throughout this application, it should be understood that both of the terms “substantially hollow” and “hollow” include both entirely hollow configurations, and configurations that are mostly, but not necessarily entirely, hollow. 
       FIG. 3  is a bottom, front end isometric view of the example muzzle brake  10  shown in  FIG. 2 . As discussed above, the example muzzle brake  10  includes the front end  11 , the nose portion  12 , the body portion  13 , the mounting portion  14 , the back end  15 , and the internal bore  17 . Additionally, in this example the nose portion  12  includes a depressed region  30 , a chamfer  31 , and an opening  32 . 
     In some embodiments, the nose portion  12  of the muzzle brake  10  includes an annular depressed region  30  and an opening  32 . 
     The annular depressed region  30  is formed at the front end  11  of the muzzle brake  10  and has a slightly tapered surface in some embodiments, which guides the ejected gases outward away from the opening  32 . 
     The opening  32  is in open communication with the internal bore  17  of the body portion  13 . In this example, an annular outside edge of annular depressed region  30  has a chamfer  31  to avoid forming sharp angles or edges. 
     An interior configuration of the nose portion  12  is illustrated and described in more detail with reference to  FIG. 12 . 
       FIG. 4  is a top, back end isometric view of the example muzzle brake shown in  FIG. 2 . As discussed above, the example muzzle brake  10  includes the front end  11 , the nose portion  12 , the body portion  13 , the mounting portion  14 , the back end  15 , and the internal bore  17 . Additionally, in this example the mounting portion  14  includes a muzzle engagement part  40 , opening  42 , screw threads  44 , flattened sides  46 , annular shoulder  48 , chamfer  50 , annular groove  52 , and top  54  of the muzzle engagement part  40 . 
     Muzzle engagement part  40  engages the muzzle end of the barrel of a firearm to secure the example muzzle brake  10  to the firearm. To secure the muzzle brake  10  to the firearm, opening  42  is placed over the muzzle end of the firearm barrel. Screw threads  44  are internal to the muzzle engagement part  40  and mate with corresponding screw threads on the muzzle end of the firearm barrel. 
     Opening  42  is in open communication with, and extends without interruption through mounting portion  14  and through to the internal bore  17  of body portion  13 . 
     Flattened sides  46  of muzzle engagement part  40  facilitate mounting of the muzzle brake  10  to the muzzle end of the firearm barrel. The muzzle brake can be mounted on the muzzle end of a firearm with any suitable tool, for example with a wrench. By way of example, a wrench can grasp the flattened sides  46  of muzzle engagement part  40  to facilitate mounting of the muzzle brake on the muzzle end of the firearm barrel. In some embodiments, the muzzle engagement part of the muzzle brake may have more or fewer flattened sides. 
     Annular shoulder  48  is at the forward end of mounting portion  14 . The forward edge of annular shoulder  48  has a chamfer  50 . Chamfer  50  creates a gradual transition from the relatively wider mounting portion  14  to the relatively narrower body portion  13  of muzzle brake  10  to avoid forming sharp angles or edges. 
     Annular groove  52  in the example muzzle brake  10  is situated between muzzle engagement part  40  and annular shoulder  48  and corresponds to a reduction in the amount of metal necessary to manufacture muzzle brake  10 , thereby additionally reducing the weight of the muzzle brake. Annular groove  52  also facilitates grasping the muzzle engagement part  40  of the muzzle brake  10  with suitable mounting tools. 
     In alternative examples of a muzzle brake in accordance with the present disclosure, the muzzle brake is mounted by alternative means (e.g. without screw threads), as will be apparent to those having skill in the art. 
       FIGS. 5-6  illustrate side views of the example muzzle brake  10  shown in  FIG. 2 .  FIG. 5  is a right side view of the muzzle brake  10 .  FIG. 6  is a left side view of the muzzle brake  10 . As discussed above, the example muzzle brake  10  includes the front end  11 , the nose portion  12 , the body portion  13 , the mounting portion  14 , the back end  15 , and the internal bore  17 . Additionally, in this example the body portion  13  of muzzle brake  10  also includes gas vents  70   a  and  70   b , projections  72   a  and  72   b , gas vent frames  74   a  and  74   b , top frame members  76   a  and  76   b , bottom frame members  78   a  and  78   b , and back frame members  80   a  and  80   b .  FIGS. 5-6  also show the flattened sides  46  of mounting portion  14 , the annular shoulder  48 , chamfer  50 , and annular groove  52  discussed above. 
     Gas vents  70   a  and  70   b  are provided to vent and redirect gas therethrough that is ejected from the muzzle end  9  of a firearm  2 . Gas vents  70   a  and  70   b  are approximately rectangles with rounded edges. In alternative embodiments, the gas vents are other shapes, including but not limited to parallelograms, triangles, circles, or ovals. 
     Projections  72   a  and  72   b  extend from the front sides of gas vents  70   a  and  70   b , respectively, and are provided to collect gas that passes through gas vents  70   a  and  70   b , respectively, and to redirect that gas in a preferred direction to reduce recoil of the firearm  2 . Projections  72   a  and  72   b  also create turbulence in gas that passes through gas vents  70   a  and  70   b , respectively. Projections  72   a  and  72   b  are approximately trapezoidal with rounded corners and extend from the body portion  13  of the muzzle brake  10 . However, the precise shape and dimensions of the projections can vary. In alternative embodiments, the projections are other shapes, including but not limited to rectangles, squares, semi-circles, as well as irregular shapes and designs. In further alternative embodiments, the projections have flared tips. 
     Gas vents  70   a  and  70   b  are bounded by gas vent frames  74   a  and  74   b , respectively. Gas vent frames  74   a  and  74   b  consist of top frame members  76   a  and  76   b , bottom frame members  78   a  and  78   b , and back frame members  80   a  and  80   b.    
     Top frame members  76   a  and  76   b , as well as bottom frame members  78   a  and  78   b , are substantially flat. The pair of top frame member  76   a  and bottom frame member  78   a , as well as the pair of top frame member  76   b  and bottom frame member  78   b , each define a distinct plane having a normal line with a component that is sideways and outward from the axis A 1  (referred to hereinafter as the longitudinal axis) that goes through the center of the body portion  13  of muzzle brake  10 , and a component that is upward and outward from the longitudinal axis A 1  of the body portion  13 . The sideways, outward components of these planes results from the gas vents&#39;  70   a  and  70   b  positioning on the right and left sides, respectively, of the body portion  13  of muzzle brake  10 . The upward, outward components of these planes results from each of the gas vents&#39;  70   a  and  70   b  being positioned with a bias towards the top of the body portion  13  of muzzle brake  10 , as discussed in greater detail below. 
     Back frame member  80   a  is formed on the annular shoulder  48  and is angled outward from the body portion  13  of the muzzle brake  10 , and likewise angled relative to the top frame member  76   a  and bottom frame member  78   a . Likewise, back frame member  80   b  is also formed on the annular shoulder  50  and is angled outward from the body portion  13  of the muzzle brake  10 , and likewise angled relative to the top frame member  76   b  and bottom frame member  78   b . The angles of back frame members  80   a  and  80   b  will be discussed in greater detail below. 
     As further shown in  FIGS. 5-6 , the exterior surface of body portion  13  of example muzzle brake  10  tapers towards nose portion  12 . The tapering of the outer surface of body portion  13  facilitates the casting process (as described below), and can also reduce the amount of material required to manufacture, and therefore the weight and cost of, the muzzle brake  10 . In an alternative embodiment, the body portion of the muzzle brake is substantially cylindrical and not tapered. 
       FIG. 7  is a top view of the example muzzle brake of  FIG. 2 . As discussed above, the example muzzle brake  10  includes the front end  11 , the nose portion  12 , the body portion  13 , the mounting portion  14 , the back end  15 , and the internal bore  17 . In this example, the body portion  13  of the muzzle brake  10  also has a top surface  16  as described above.  FIG. 7  also shows the projections  72   a  and  72   b , gas vent frames  74   a  and  74   b , top frame members  76   a  and  76   b , and back frame members  80   a  and  80   b  as discussed above. 
     As shown in  FIG. 7 , muzzle brake  10  has an angle x 1  between a rearward facing gas capturing surface of the projection  72   a  and top frame member  76   a , and an equivalent angle x 1  between a rearward facing gas capturing surface of the projection  72   b  and the top frame member  76   b . There is also an angle y 1  between back frame member  80   a  and an imaginary line B 1  extending from top frame member  76   a , and an equivalent angle y 1  between back frame member  80   b  and an imaginary line B 2  extending from top frame member  76   b . In this exemplary embodiment, x 1 =y 1 . 
     The angled orientation of the projections  72   a  and  72   b  relative to the body portion  13  of the muzzle brake  10  helps to create the desired turbulence and redirection of expanding gases generated during firing of a firearm to reduce or neutralize recoil. 
     When the muzzle brake  10  is fully mounted on the firearm  2 , the apex of the muzzle brake, as defined by an imaginary line C 1  on the top surface  16  of the muzzle brake body portion  13  of the muzzle brake  10  that bisects the top surface  16  between the projections  72   a  and  72   b , is at the 12 o&#39;clock position as measured when the firearm is being held in a conventional firing position. To facilitate this desirable mounted configuration, the mounting portion  14  of the muzzle brake  10  is configured to screw onto the muzzle end of the barrel such that the screw threads stop advancing onto the muzzle end of the barrel when the aforementioned apex of the muzzle brake reaches the 12 o&#39;clock position. Mounting the muzzle brake with its apex at the 12 o&#39;clock position optimizes the direction of the deflection of exploding gases by projections  72   a  and  72   b  and optimizes the angle of capture and redirection of gas flow through muzzle brake&#39;s gas vents to reduce or eliminate both axial recoil and upward kick of the firearm resulting from firing. 
     In an alternative embodiment, washers or other annular discs (through which a projectile can travel without impediment) can be inserted into the threaded cavity in the mounting portion  14  of the muzzle brake  10  to decrease the depth of the cavity such that the apex of the muzzle brake aligns with the 12 o&#39;clock position when the threads are fully screwed onto the muzzle end of the barrel and stop rotating. In one non-limiting example, a desired number of suitable washers having a thickness of 1/2000 th  of an inch or less can be arranged together and used for this purpose to ensure a high degree of precision with respect to achieving a 12 o&#39;clock position for the apex of the muzzle brake when the firearm is held in the conventional firing position. 
       FIG. 8  is a cross-sectional view of the example muzzle brake  10  of  FIG. 2  along line  8 - 8  in  FIG. 7 . As discussed above, the example muzzle brake  10  includes a body portion  13 . Body portion  13  has top surface  16 , bottom surface  18 , and projections  72   a  and  72   b  extending therefrom.  FIG. 8  also shows the opening  32  discussed above. 
     As shown in  FIG. 8 , top surface  16  of the body portion  13  of muzzle brake  10  has a width W 1  that is narrower than a width W 2  of bottom surface  18 . This is due to the positioning bias of the projections  72   a  and  72   b , and corresponding gas vents situated directly behind the projections, towards top surface  16  and away from bottom surface  18 . The bias of the gas vents, and of the projections  72   a  and  72   b , towards the top surface  16  of the muzzle brake (as discussed in greater detail below), provides an upward component to the velocity of expelled gases through the gas vents, thereby reducing or neutralizing upward kick/recoil of the firearm. 
       FIG. 9  is a bottom view of the example muzzle brake of  FIG. 2 . As discussed above, the example muzzle brake  10  includes the front end  11 , the nose portion  12 , the body portion  13 , the mounting portion  14 , and the back end  15 .  FIG. 9  also shows the exterior surface  19  of the body portion  13 , the projections  72   a  and  72   b , bottom frame members  78   a  and  78   b , and back frame members  80   a  and  80   b , as discussed above. Additionally, in this example the projections  72   a  and  72   b  extending from the body portion  13  of the muzzle brake  10  have gas capturing surfaces  90   a  and  90   b , respectively. 
     Gas capturing surfaces  90   a  and  90   b  capture expanding gas generated from firing a firearm, and/or create turbulence in those gases to reduce or neutralize recoil of the firearm. Gas capturing surfaces  90   a  and  90   b  also redirect expanding gases both upwards, and backwards towards the shooter to reduce or neutralize recoil of the firearm when the apex of muzzle brake is mounted and aligned with the 12 o&#39;clock position as described above. 
     As further shown in  FIG. 9 , muzzle brake  10  has an angle x 2  between the gas capturing surface  90   a  of projection  72   a  and bottom frame member  78   a , and an equivalent angle x 2  between the gas capturing surface  90   b  of projection  72   b  and bottom frame member  78   b . There is also an angle y 2  between back frame member  80   a  and an imaginary line B 3  extending from back frame member  80   a , and an equivalent angle y 2  back frame member  80   b  and an imaginary line B 4  extending from back frame member  80   b.    
     As further shown in  FIG. 9 , the wings  72   a  and  72   b  extend beyond the profile of body portion  13  of the muzzle brake  10 . Thus, the gas capturing surfaces  90   a  and  90   b  of projections  72   a  and  72   b , respectively, are external to the exterior surface  19  of the body portion  13  of the muzzle brake. This allows for provision of a narrower body portion  13  of the muzzle brake than would be required were the gas capturing surfaces interior to the wall (i.e. within the profile) of body portion  13 . The external nature of projections  72   a  and  72   b  reduces the weight of the muzzle brake  10 , and accordingly reduces the cost of manufacturing it. 
     Moreover, were the gas capturing surfaces built into (i.e. internal to) the walls of the body portion, the walls of the body portion necessarily would be thicker to accommodate the angled gas capturing surfaces. The body portion of the muzzle brake, and therefore the muzzle brake as a whole, would thereby have to be wider in diameter to accommodate this extra wall thickness without reducing the diameter of the body portion&#39;s hollow internal bore through which the projectile travels, thereby increasing the weight of the muzzle brake and the amount of material needed to manufacture it. 
     Referring to both  FIGS. 7 and 9 , in the example muzzle brake  10 , x 1 =x 2 =y 1 =y 2 , and each is about 60°. In alternative embodiments, each of x 1 , y 1 , x 2 , and y 2  have a value from about 45° to about 70°. Other possible embodiments have other angles x 1 , y 1 , x 2 , and y 2  outside of these ranges. According to some examples of these further embodiments x 1 =x 2 =y 1 =y 2 . According to other examples of these further embodiments, x 1 &gt;y 1  and x 2 &gt;y 2 . As discussed below with reference to  FIG. 15 , these angle magnitude relationships result from an example manufacturing process of muzzle brakes in accordance with the present disclosure. However, other angles and/or relationships between the various angles can be provided in other embodiments. 
       FIG. 10  is a front view of the muzzle brake of  FIG. 2 . As discussed above, the example muzzle brake  10  includes the body portion  13 , having a top surface  16  and bottom surface  18 .  FIG. 10  also shows the annular depressed region  30  and the opening  32  at the nose of the muzzle brake  10 , as well as the projections  72   a  and  72   b  extending from the body portion  13  as discussed above. 
     As further shown in  FIG. 10 , projections  72   a  and  72   b  of muzzle brake  10  are biased towards the top surface  16  of the body portion  13  by an angle α. Angle α is the angle measured between a horizontal axis of the muzzle brake A 2 , and central radial axes D 1  and D 2  originating in the center of the muzzle brake  10  and bisecting the projections  72   a  and  72   b , respectively. In the example shown in the figure, a is about 7°. In alternative embodiments of a muzzle brake in accordance with the present disclosure, a is in a range from about 0° to about 20°. In some examples, a is in a range from about 4° to about 10°. In further alternative embodiments, the angle between axes A 2  and D 1  need not be identical to the angle between axes A 2  and D 2 . 
       FIG. 11  is a back view of the muzzle brake of  FIG. 2 . As discussed above, the example muzzle brake  10  includes a back end  15 , and an annular depressed region  30  and opening  32  in the nose of the muzzle brake  10 .  FIG. 11  also shows the rear interior surface  96  of annular depressed region  30 . 
       FIG. 12  is a cross-sectional view of the muzzle brake of  FIG. 2  along line  12 - 12  in  FIG. 11 . As discussed above, the example muzzle brake  10  includes a front end  11 , body portion  13 , back end  15 , and internal bore  17 .  FIG. 12  also shows annular depressed region  30 , opening  32 , gas vent  70   b , projection  72   b  with its gas capturing surface  90   b , and rear interior surface  96  of the annular depressed region  30  as discussed above.  FIG. 12  also shows an interior surface  98  of the body portion  13  of the muzzle brake  10  and an exterior, front surface  99  of annular depressed region  30 . 
     As shown in  FIG. 12 , at the juncture of the rear interior surface  96  of the annular depressed region  30  and the interior surface  98  of the body portion  13  of the muzzle brake  10 , there is an angle z therebetween. In the example embodiment shown in  FIG. 12 , angle z is about 75°. In some embodiments the angle z is in a range from about 70° to about 80°. Other possible embodiments have an angle z outside of these ranges. 
     The rear interior surface  96  of annular depressed region  30  creates turbulence in the propellant gases generated by firing the firearm as those gases move along the internal bore  17  of body portion  13  and seek to escape through opening  32  through which the projectile exits, thereby reducing or neutralizing recoil. 
     As further shown in  FIG. 12 , both the rear interior surface  96  and exterior, front surface  99  of the annular depressed region  30  are depressed, providing a generally concave profile to the exterior, front surface  99  of annular depressed region  30 , and a generally convex profile to the rear interior surface  96  of annular depressed region  30 . The concavity of the exterior, front surface  99  of annular depressed region  30  helps to avoid sharp angles or edges around opening  32 . As discussed above, the convexity of the rear interior surface  96  of annular depressed region  30  captures exploding, propellant gases that would otherwise exit the front of the muzzle through opening  32 , and creates turbulence in those gases, thereby reducing recoil/kick of the firearm. In some embodiments of the present disclosure the shape of the concavity of the exterior, front surface  99  is bowl-shaped. Similarly, in some embodiments, the convexity of rear interior surface  96  is bowl-shaped. In other embodiments the shape of the concavity of the exterior, front surface of the annular depressed region and/or the shape of the convexity of the interior, rear surface of the annular depressed region is/are approximately conical or frusto-conical. 
       FIG. 13  illustrates an example method  110  of manufacturing muzzle brakes in accordance with the present disclosure. In this example, the method  110  includes operations  112 ,  114 , and  116 . 
     In accordance with this example method  110 , in an operation  112  a model muzzle brake is constructed, in an operation  114  copies are made of the model muzzle brake model, and in operation  116  the muzzle brake copies are machined into their final configuration for mounting on, and use with, a firearm. 
       FIG. 14  illustrates an example method  120  of manufacturing a muzzle brake model, showing example steps that can be taken to complete operation  112  of  FIG. 13 . In this example the method  120  includes operations  122 ,  124 , and  126 . 
     In accordance with this example method  120  in an operation  122  a blank of material is provided that is sufficiently sized from which to cut a muzzle brake in accordance with the present disclosure. In an operation  124 , the blank of material is cut to create the features of the muzzle brake. In an operation  126  the surface and edges of the muzzle brake&#39;s features are smoothed and polished to complete the muzzle brake model. 
     In some embodiments of example method  120 , operation  124  is performed by a tool used to cut and shape material, such as a die. In some embodiments of example method  120 , operation  126  is performed with a sanding device, a shaving device, or both. 
     It should be noted that muzzle brakes in accordance with this present disclosure can be manufactured through example method  120  alone, without requiring operations associated with methods  130  and  170  described below. 
       FIG. 15  illustrates an example method  130  of investment casting to make copies of a muzzle brake model. The method  130  is one example of the operation  114  shown in  FIG. 13 . In this example, the method  130  includes operations  132 ,  134 ,  136 ,  138 ,  140 ,  142 ,  144 ,  146 ,  148 ,  150 ,  152 ,  154 , and  156 . 
     In accordance with this example method  130 , in an operation  132 , a muzzle brake mold is created using a model muzzle brake such as that made by method  120  discussed above in connection with  FIG. 14 . In one example embodiment of this method, the mold is made from aluminum. In an operation  134 , liquid wax is injected into the mold in accordance with known methods to create a wax muzzle brake that is a replica of the model muzzle brake used to create the mold. In an operation  136 , the wax is allowed to solidify in the mold. In an operation  138  air-powered slides on either side of the mold are retracted from the mold at an angle toward the back end of the wax muzzle brake, opening up gas vents  70   a  and  70   b  and resulting in back frame members  80   a  and  80   b  behind the gas vents  70   a  and  70   b , respectively (see  FIGS. 5-6 ). 
     The air-powered slides are retracted from the mold in this direction (as opposed to straight outward or towards the nose of the muzzle brake) so as not to disturb or interfere with projections  72   a  and  72   b , and to maintain the angles x 1  and x 2  of the projections (see  FIGS. 7 and 9 ). Therefore, to facilitate the retraction of the air-powered slides from the mold and to maintain the desired angles of the projections  72   a  and  72   b  off the body of the muzzle brake, angle y 1 ≦angle x 1  (see  FIG. 7 ); and angle y 2 ≦angle x 2  (see  FIG. 9 ). 
     In an operation  140  the hardened wax muzzle brake is removed from the mold. In an operation  142 , operations  132  through  140  are repeated one or more times to create multiple wax muzzle brakes. With respect to the wax muzzle brake&#39;s features and dimensions, the wax muzzle brakes differ from the final product only in that they do not contain screw threads in the mounting portion or an opening at the nose through which the projectile exits the muzzle brake, which can formed in a separate process at the end of the example manufacturing method  130 . In an alternative manufacturing process, the opening in the nose through which the projectile exits the muzzle brake is molded as a feature of the wax muzzle brake(s). It should be noted that the method  130  can be completed to create a single muzzle brake copy by optionally omitting operation  142 . 
     In an operation  144 , multiple wax muzzle brakes are attached to a wax tree-like structure. The tree-like structure may have one or multiple branches to which one or more wax muzzle brakes are attached. The muzzle brakes are attached via any suitable means (e.g., by melting) from their back ends to the tree-like structure. The tree-like structure is designed according to known investment molding methods such that when the wax is melted away from the subsequently formed ceramic molds as described below, a complex of channels is opened permitting access to each ceramic muzzle brake mold from a common entrance point through which molten metal is poured. 
     In an operation  146 , a ceramic mold of the muzzle brake tree structure is made. To create the ceramic molds, the wax tree-like structure with attached wax muzzle brakes is prepared for and dipped in a ceramic slurry in accordance with known methods. Once the ceramic hardens and dries on the wax, it is treated with sand, and the process can be repeated multiple times, adding layers of ceramic and sand until the desired thickness and strength of ceramic is achieved. 
     In an operation  148 , the wax is melted out of the ceramic mold of the muzzle brake tree-like structure through an entrance/exit point prepared for this purpose in accordance with known methods, leaving a ceramic mold of a tree-like structure of muzzle brakes. 
     In an operation  150 , the ceramic tree-like structure is heated. 
     In an operation  152 , a molten metal alloy is poured through the entrance point of the ceramic tree-like structure into the hollowed out ceramic muzzle brake molds, and allowed to cool and harden. In one exemplary embodiment, the alloy used is 17-4 PH stainless steel, though it will be understood that a variety of metals and/or metal alloys would be suitable for the muzzle brake of the present disclosure. 
     In some embodiments of example manufacturing method  130 , the model muzzle brake, molds, and muzzle brake copies are designed such that the exterior surface of the body portion of each muzzle brake is tapered towards the nose. This facilitates the advancement of the molten metal into the individual ceramic muzzle brake molds during the casting operation  152 , resulting in a more refined and consistent final product with fewer irregularities. A tapered muzzle brake also requires less material to manufacture and weighs less than a non-tapered or more cylindrical muzzle brake. 
     In an operation  154 , the ceramic shell is removed from the metal cast muzzle brakes through known means, such as vibration treatment. 
     In an operation  156 , the individual metal muzzle brake copies are then removed from the muzzle brake tree structure in accordance with known methods, and sanded and/or polished as necessary to remove imperfections. 
       FIG. 16  illustrates an example method  170  of machining one or more muzzle brake model copies into their final configuration for mounting on, and use with, a firearm. The method  170  is an example of operation  116  shown in  FIG. 13 . In this example, method  170  includes operations  172  and  174 . 
     In the operation  172 , the opening through which the projectile exits the muzzle brake is drilled in the nose of each muzzle brake copy. In an alternative manufacturing process, operation  172  is omitted, as the opening in the nose through which the projectile exits the muzzle brake is cast as a feature of the muzzle brake(s) earlier in the manufacturing process. In an operation  174 , screw threads are cut into the mounting portion of each muzzle brake to complete the manufacturing process. 
     In one embodiment, operations  172  and  174  create an opening and screw threads, respectively, that are configured for the barrel and ammunition of a 556 caliber rifle. It should be noted, however, that muzzle brakes in accordance with the present disclosure can be configured to operate with a variety of firearms and calibers without departing from the disclosures herein. 
       FIG. 17  is a top, rear, left side perspective view of an alternative embodiment of a muzzle brake in accordance with the present disclosure. In this example, the muzzle brake  210  includes a front end  211 , a nose portion  212 , a body portion  213 , a mounting portion  214 , a back end  215 , a top  216  and an internal bore  217 . The mounting portion  214  includes a muzzle engagement part  240 , opening  242 , screw threads  244 , flattened sides  246 , annular shoulder  248 , and annular groove  252 . 
     The body portion  213  of example muzzle brake  210  also includes a first pair of projections  272   a  and  272   b  having gas capturing surfaces  290   a  and  290   b , respectively, a second pair of projections  300   a  and  300   b , and an annular wall  302 . The annular wall  302  includes opening  304  and rear-facing surface  306 . The second pair of projections  300   a  and  300   b  include gas capturing surfaces  308   a  and  308   b , respectively. 
     In this example muzzle brake  210  the front end  211  is opposite the back end  215 . Top  16  faces upwards when the muzzle brake  210  is properly mounted to a firearm that is being held in a conventional firing position. 
     Muzzle engagement part  240  engages the muzzle end of the barrel of a firearm to secure the example muzzle brake  210  to the firearm. To secure the muzzle brake  210  to the firearm, opening  242  is placed over the muzzle end of the firearm barrel. Screw threads  244  are internal to the muzzle engagement part  240  and mate with corresponding screw threads on the muzzle end of the firearm barrel. 
     Opening  242  is in open communication with, and extends without interruption through mounting portion  214  and through to the internal bore  217  of body portion  213 . 
     Flattened sides  246  of muzzle engagement part  240  facilitate mounting of the muzzle brake  210  to the muzzle end of the firearm barrel. The muzzle brake can be mounted on the muzzle end of a firearm with any suitable tool, for example with a wrench. By way of example, a wrench can grasp the flattened sides  246  of muzzle engagement part  240  to facilitate mounting of the muzzle brake on the muzzle end of the firearm barrel. In some embodiments, the muzzle engagement part of the muzzle brake may have more or fewer flattened sides. 
     Annular shoulder  248  is at the forward end of mounting portion  214 . 
     Annular groove  252  in the example muzzle brake  210  is situated between muzzle engagement part  240  and annular shoulder  248  and corresponds to a reduction in the amount of metal necessary to manufacture muzzle brake  210 , thereby additionally reducing the weight of the muzzle brake. Annular groove  252  also facilitates grasping the muzzle engagement part  240  of the muzzle brake  210  with suitable mounting tools. 
     In alternative examples of a muzzle brake in accordance with the present disclosure, the muzzle brake is mounted by alternative means (e.g. without screw threads), as will be apparent to those having skill in the art. 
     Projections  272   a  and  272   b , and  300   a  and  300   b , extend from the body portion  213  and are provided to collect gas that passes through internal bore  217  when firing a firearm, and to redirect that gas in a preferred direction to reduce recoil of the firearm. Projections  272   a ,  272   b ,  300   a , and  300   b  also create turbulence in propellant gas generated when firing a firearm. Projections  272   a ,  272   b ,  300   a  and  300   b  are approximately trapezoidal with rounded corners and extend from the body portion  213  of the muzzle brake  210 . However, the precise shape and dimensions of each of the projections can vary. In alternative embodiments, one or more of the projections are other shapes, including but not limited to rectangles, squares, semi-circles, as well as irregular shapes and designs. In further alternative embodiments, one or more of the projections have flared tips. 
     Projections  272   a ,  272   b ,  300   a , and  300   b  extend from locations on the body portion  213  of muzzle brake  210  that are biased towards the top surface  216  of the body portion  213 . This top-biasing counteracts upward kick or recoil of a firearm as discussed above. 
     Annular wall  302  is disposed within internal bore  217  of body portion  213  and between projections  300   a  and  300   b . Opening  304  in annular wall  302  permits passage of a projectile therethrough. Rear-facing surface  306  of annular wall  302  captures propellant gases travelling through internal bore  217  generated while firing a the firearm and helps redirect such gas towards projections  300   a  and  300   b.    
     Gas capturing surfaces  290   a ,  290   b ,  308   a , and  308   b  are angled both upwards toward top  216  of muzzle brake  210  to redirect propellant gases upward, and rearwards toward back end  215  of muzzle brake  210  to redirect propellant gases rearward. In addition to extending from body portion  213 , projections  300   a  and  300   b  extend from opposing edges of annular wall  302  as shown in  FIG. 19 .  FIG. 18  is a top view of the muzzle brake of  FIG. 17 . The example muzzle brake  210  of  FIG. 18  includes front end  211 , nose portion  212 , body portion  213 , mounting portion  214 , back end  215 , top  216 , internal bore  217 , a first pair of projections  272   a  and  272   b , and a second pair of projections  300   a  and  300   b  as discussed above. In this example, the muzzle brake  210  also includes a first pair of gas vents  310   a  and  310   b , and a second pair of gas vents  312   a  and  312   b.    
     Gas vents  310   a ,  310   b ,  312   a , and  312   b  are in open communication with internal bore  217  of body portion  213  of example muzzle brake  210 . Each pair of gas vents— 310   a  and  310   b , and  312   a  and  312   b , respectively, is symmetrically biased towards the top  216  of muzzle brake  210 . Propellant gas generated during firing of a firearm is redirected through gas vents  310   a ,  310   b ,  312   a , and  312   b , thereby counteracting barrel axial recoil of the firearm in the manner described above. In addition, the bias of the gas vents  310   a ,  310   b ,  312   a , and  312   b  towards the top  216  of the muzzle brake  210  counteracts upward recoil of the firearm in the manner described above. 
       FIG. 19  is a cross-sectional view of the muzzle brake of  FIG. 17  along line  19 - 19  in  FIG. 17 . The example muzzle brake  210  of  FIG. 19  includes front end  211 , nose portion  212 , body portion  213 , mounting portion  214 , back end  215 , internal bore  217 , muzzle engagement part  240 , screw threads  244 , a first pair of projections  272   a  and  272   b , a second pair of projections  300   a  and  300   b , and annular wall  302  with opening  304  therein as discussed above. In this example, the nose portion  212  of muzzle brake  210  also includes a depressed region  230  and opening  232  through which a projectile exits the muzzle brake, the depressed region  230  including an interior, rear surface  296  and an exterior, front surface  299 . 
     In a typical firing of the firearm, the projectile exits the barrel of the firearm and enters the example muzzle brake  210  through its back end  215 . The projectile then passes through mounting portion  214  into the internal bore  217  of the body portion  213 . The projectile then passes through opening  304  in annular wall  302 , continues through internal bore  217  and ultimately exits the muzzle brake through opening  232  in nose portion  212 . 
     As discussed above, some of the propellant gas generated from firing the firearm are redirected by annular wall  302 , and/or projections  270   a ,  270   b ,  300   a , or  300   b . Those propellant gases that make it through annular wall  302  (through opening  304 ) and past the projections  270   a ,  270   b ,  300   a , and  300   b  toward the nose portion  212 , can encounter interior, rear surface  296  of annular depressed region  230 . Interior, rear surface  296  of annular depressed region  230  creates turbulence in those propellant gases as they continue to travel along the internal bore  217  of body portion  213  toward opening  232  through which the projectile exits the muzzle brake. This turbulence acts to further reduce or neutralize recoil of the firearm as discussed above. 
     As further shown in  FIG. 19 , both the rear interior surface  296  and exterior, front surface  299  of the annular depressed region  230  are depressed, providing a generally concave profile to the exterior, front surface  299  of annular depressed region  230 , and a generally convex profile to the interior, rear surface  296  of annular depressed region  230 . The concavity of the exterior, front surface  299  of annular depressed region  230  helps to avoid sharp angles or edges around opening  232 . As discussed above, the convexity of the rear interior surface  296  of annular depressed region  230  captures exploding, propellant gases that would otherwise exit the front of the muzzle through opening  232 , and creates turbulence in those gases, thereby reducing recoil/kick of the firearm. In some embodiments of the present disclosure the shape of the concavity of the exterior, front surface  299  is bowl-shaped. Similarly, in some embodiments, the convexity of rear interior surface  296  is bowl-shaped. In other embodiments the shape of the concavity of the exterior, front surface of the annular depressed region and/or the shape of the convexity of the interior, rear surface of the annular depressed region is/are approximately conical or frusto-conical. 
     The various embodiments described above are provided by way of illustration only and should not be construed to limit the claims attached hereto. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the following claims.