Abstract:
An apparatus for use with a shotgun that includes an assembly having an interchangeable choke and compensator, and a lock nut for securing the compensator in a selected alignment with the choke. The current invention allows for shotguns, chokes, and compensators to be used interchangeably while still maintaining the correct positioning of each part relative to the others.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to shotgun parts. Specifically this invention relates to interchangeable shotgun chokes and compensators. 
       BACKGROUND OF THE INVENTION 
       [0002]    A shotgun choke is a regulated constriction at the end of the barrel bore to control the pattern of pellet density. The shooter selects the choke which will best suit his needs; e.g. the shooter may want a large pattern of pellets to reduce aiming error, or a small pattern with a high density of pellets for maximum impact at long ranges. A choke is most effective when used for a discrete yardage range. The shooter sacrifices pattern performance when a given choke is used at all yardages. An example of this is when a shooter tries to use an improved modified choke, ideal at 16 yard trap, for a target at the 27 yard line. The full choke (maximum constriction) would be better at the 27 yard line to give enough pellet density to consistently break targets. 
         [0003]    Chokes are well known in the art. U.S. Pat. No. 797,345 describes a shotgun with exterior threading on the end of the muzzle for accepting chokes containing interior threading or a muzzle cap with interior threading. U.S. Pat. No. 1,455,661 describes interchangeable chokes that contain external threading and are screwed into the muzzle. U.S. Pat. No. 2,700,839 describes a single choke that can be adjusted to produce different shot patterns. 
         [0004]    A shotgun compensator is used to reduce recoil, sound and loading times. Upon discharge or firing of a shotgun, a projectile is typically forced out of a cartridge by a propellant. The burned propellant is an expanding composition of gasses that urge the projectile through the barrel and exit the barrel behind the projectile. The exiting gasses interact with the surrounding air and create recoil and muzzle jump. Compensators reduce the recoil by gradually releasing the pressure produced by the blast through perforations at the end of the barrel. This process usually takes place while the bullet is still in the barrel. Because the grip of the gun is below the barrel, the recoil force may torque the gun in the hand of the shooter producing “muzzle flip.” The muzzle flip (an upward motion of the hand and gun after firing) slows down the shooter by increasing the time to recover and line-up the sights on the next target. Competitive sports and tactical applications use the compensating effect of releasing the gasses through ports in the upper end of the barrel. These ports are called compensating ports and will exhaust the gases up rather than around the barrel, which will cause a downward force on the barrel. The closer these ports are to the end of the barrel the greater the counteracting force of torque. This force aids in counteracting muzzle flip and helps to keep the barrel on target, allowing the shooter to fire at a much faster rate while increasing accuracy. 
         [0005]    Compensators are well known in the art and may also be known as muzzle brakes. U.S. Pat. No. 4,207,799 describes a compensator on a handgun located on the top of the barrel. U.S. Pat. No. 5,698,810 describes a weight being attached interchangeably to the end of a compensator. U.S. Pat. No. 6,604,445 describes specific gas trap compensator that is located on the top of a firearm barrel. 
         [0006]    Compensators and chokes have been used together in the art, however, there are several inherent problems with the current assemblies. Current choke and compensator designs require a specific compensator for each choke, compensators that are on the shotgun side of the chock, or chokes that are irreversibly attached to compensators in order to maintain correct alignment of the shotgun and compensator. U.S. Pat. No. 2,589,171 describes a compensator which contains vents around the entirely of the muzzle which is attached to and located on the shotgun side of the choke. U.S. Pat. No. 3,367,055 also describes a compensator and choke combination with the choke internal to the compensator. 
         [0007]    The current invention allows for shotguns, chokes, and compensators to be used interchangeably while still maintaining the correct positioning of each part relative to the others. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention provides for an apparatus for use with a shotgun comprising an assembly that includes an interchangeable choke and compensator, and a lock nut for securing the compensator in a selected alignment with the choke. The choke has a first and second end and each end includes external threading. The lock nut includes internal threading and a pair of wrench flats. The compensator has a first end that includes internal threading and further includes two compensator exit ports, two expansion chambers, and two compensator side ports. A second embodiment provides to an assembly that includes a plurality of an interchangeable chokes, a compensator configured to attach to the chokes, and a lock nut for securing the compensator in a selected alignment with the chokes. 
         [0009]    The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
           [0011]      FIG. 1  is a perspective view of the inventive assembly that includes a choke, a locking nut and a compensator; 
           [0012]      FIG. 2  is a cross-sectional view of the assembly of  FIG. 1 ; 
           [0013]      FIG. 3  is a perspective view of the choke, locking nut and compensator separated from each other; 
           [0014]      FIG. 4  is perspective view of the locking nut of  FIG. 3 ; 
           [0015]      FIG. 5  is a perspective view of the compensator of  FIG. 3 ; 
           [0016]      FIG. 6  is a cross-sectional side view of the compensator of  FIG. 5 ; and 
           [0017]      FIG. 7  is a cross-sectional view along lines  7 - 7  of the compensator of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    In view of the foregoing disadvantages inherent in the prior art, the present invention provides an assembly of an interchangeable choke and compensator wherein different chokes may be used with the same compensator and different compensators may be used with the same choke. 
         [0019]    To attain this, the present invention generally comprises an assembly  10  that includes a choke  12  having outside threading  11  on a first end  20  adapted to be threaded into threading on the inside of a barrel of a shotgun and outside threading  11  on a second end  22  adapted to be threaded into a lock nut  14  and compensator  16 . The lock nut  14  tightens the compensator  16  on the second end  22  of the choke  12  and allows for correct positioning of the compensator  16  relative to the shotgun. The compensator  16  has corresponding internal threading  13  on a first end  26  and adjacent vents in the body of the compensator  16  for redirecting gas. ( FIGS. 1-3 ) 
         [0020]    The present invention thus provides an assembly of parts  10  for use with a shotgun in which the one shotgun may be used with multiple chokes and one compensator  16 , and a single choke  12  may be used with a variety of compensators. 
         [0021]    The locking nut  14  has internal threading  24  and a pair of corresponding wrench flats  28  on the outside surface of the locking nut. The wrench flats  28  to assist the shooter in securing the locking nut  14  to the compensator and choke. ( FIG. 5 ) 
         [0022]    The compensator  16  includes two direction ports  30  to vent the gas and two expansion chambers  32  that provide for a gas expansion surface area. Two compensator exit ports  38  restrict the diameter of the compensator and two areas of tapered geometry  36  allow for a smooth transition to the restrictive diameter of the exit ports  38 . The compensator  16  also included three flats  18  on a portion of its outside surface. The flats  18  assist in lining up the direction ports relative to the shotgun barrel. ( FIGS. 5-7 ) 
         [0023]    While the choke  12  and compensator  16  fulfill their respective, particular objectives and requirements, the assembly of the parts  10  departs from the conventional concepts and designs of the prior art, and in so doing provides an assembly  10  primarily developed for the purpose of allowing the user to interchange a variety of chokes  12  while using one compensator  16  or interchangeably using a variety of compensators with one choke  12 . 
         [0024]    Since the threading on the shotgun barrel and the threading in conventional compensated chokes (a choke and compensator that are irreversibly attached or chokes with non-interchangeable compensators) known in the art are not timed it presents a problem on how to screw in the compensated choke  12  while still having the compensator ports  30  pointing in the right direction to achieve maximum benefit (in most cases the vents will be pointed upward). Incorrectly placed compensator ports  30  may increase the muzzle flip, rather than decrease it, leading to an even greater loss of accuracy and recovery time than suffered with no compensator. The present invention overcomes this problem by using the lock nut  14 . As used herein the lock nut may also be called a nut, a locking nut, a lock nut, a timing nut, a compensator nut and/or a fine tuning lock nut. 
         [0025]    It is envisioned that in using the assembly  10 , an individual will attached the compensator  16  to the choke  12  which will already be attached securely to a shotgun. The locking nut  14  is threaded onto the external threading  11  on the second end  22  of the choke  12  and then the first end  26  of the compensator  16  is screwed onto the second end  22  of the choke  12  stopping when the compensator  16  is properly aligned with the shotgun. The locking nut  14  is then reverse screwed (unscrew towards the compensator) such that it tightens against the compensator  16 , securely fastening the compensator  16  in the correct alignment. In this way the assembly of the present invention  10  (the choke  12 , locking nut  14 , and compensator  16 ) forms a secure unit while still maintaining interchangeability and the proper positioning of the compensator  16  relative to the shotgun. 
         [0026]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.