Abstract:
Apparatus and method for controlling vibrations of a firearm barrel to increase firing accuracy and shot uniformity. A post is attached to the firearm barrel, and a locking bolt is screwed into the post. In the case of a rifle or similar weapon, the bolt preferably extends through an escutcheon which serves to attach the stock to the barrel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the filing of U.S. Provisional Patent Application Ser. No. 60/808,319, entitled “Firearm Barrel Vibrational Stabilizing Device”, filed on May 24, 2006, and the specification thereof is incorporated herein by reference. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention (Technical Field) 
         [0003]    The present invention is a device and system to dampen or control barrel vibrations which occur when a firearm, particularly a rifle, is fired. 
         [0004]    2. Background Art 
         [0005]    Note that the following discussion refers to a number of publications and references. Discussion of such publications herein is given for more complete background of the scientific principles and is not to be construed as an admission that such publications are prior art for patentability determination purposes. 
         [0006]    When firing a projectile through a firearm, vibrations in the firearm barrel are caused, which results in lower targeting accuracy and less uniformity from shot to shot.  FIG. 1  schematically depicts vibrations  12  of a segment of barrel  20 . The vibrations typically comprise standing waves, with certain locations on the barrel corresponding to maximum amplitudes of the standing waves, and other locations, or nodes, corresponding to minimum standing wave amplitudes. The standing wave frequency and maximum amplitude are typically highly dependent on the specific design, dimensions, and materials of the firearm. A description of barrel vibrations may be found in U.S. Pat. No. 2,372,568, incorporated herein by reference. 
       SUMMARY OF THE INVENTION (DISCLOSURE OF THE INVENTION) 
       [0007]    The present invention is an apparatus for controlling vibrations of a firearm barrel, the apparatus comprising a post comprising an at least partially threaded interior cavity, the post attached to the barrel at a location for controlling vibrations of the barrel, and a threaded bolt screwed into the cavity, the bolt at least partially securing the firearm stock to the barrel. The location is preferably approximately a point of maximum vibration of the barrel. The barrel preferably comprises a recess for receiving the post. The post is preferably hard soldered or welded to the barrel, or is optionally integrally formed with the barrel. The tension of the bolt is preferably adjustable. The barrel is preferably substantially free to vibrate from approximately the location of the bolt to a muzzle of the barrel. The bolt preferably comprises a hole for receiving a sling or a sling swivel post. The apparatus preferably further comprises an escutcheon for receiving the bolt and securing the stock to the barrel. The escutcheon preferably comprises a metal or a hard wood. 
         [0008]    The present invention is also a method for controlling vibrations of a firearm barrel, the method comprising the steps of attaching a post comprising an at least partially threaded interior cavity to a firearm barrel at a location suitable for controlling vibrations of the barrel, inserting a bolt through an opening of a firearm stock, and screwing the bolt into the cavity, thereby at least partially securing the stock to the barrel. The attaching step preferably comprises welding or hard soldering the post to the barrel. The location is preferably approximately a point of maximum vibration of the barrel. The method preferably further comprises the step of forming a recess in the barrel for receiving the post. The attaching step optionally comprises integrally forming the post during manufacture of the barrel. The method preferably further comprises the step of adjusting a tension of the bolt. The method preferably further comprises the step of attaching a sling or sling swivel post to the bolt. The inserting step preferably comprises inserting the bolt through an escutcheon inserted in the stock. The method preferably further comprises the step of shaping the escutcheon during shaping of the stock. The method preferably further comprises the step of permitting the barrel to vibrate substantially freely from the location of the post to a muzzle of the barrel. 
         [0009]    An object of the present invention is to dampen vibrations of a firearms barrel during firing. 
         [0010]    An advantage of the present invention is improved firearm accuracy and uniformity from shot to shot. 
         [0011]    Another advantage of the present invention is that for a rifle the device is preferably mounted to the barrel through the rifle&#39;s wooden forearm or stock, where the strongest vibrations typically occur. 
         [0012]    Other objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating a preferred embodiment of the invention and are not to be construed as limiting the invention. In the drawings: 
           [0014]      FIG. 1  is a schematic showing standing wave vibrations of a section of a firearm barrel; 
           [0015]      FIGS. 2   a - 2   c  show an exploded cross sectional view of a segment of an embodiment of the present invention; and 
           [0016]      FIGS. 3   a - 3   e  depict multiple methods of fastening the stabilizing post to a section of the firearm barrel. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Best Modes for Carrying Out the Invention 
       [0017]    The present invention is a device for dampening, stabilizing, or controlling barrel vibrations caused by firing a firearm, particularly but not limited to a rifle. The present invention preferably forces the barrel to vibrate approximately the same from shot to shot. It also preferably controls vibrational nodes of the barrel so that different weight projectiles having various velocities may be used with more accuracy to a given point of aim. 
         [0018]    Stabilizer post  10  of the present invention is preferably located at a position of maximum vibration of firearm barrel  20  as shown in  FIG. 1 . The location providing optimal vibration control may be different for any particular combination of firearm and ammunition and may be determined theoretically, by simulations, or empirically. One or more devices may alternatively be located at nodes or other positions along the barrel in order to provide desired results. 
         [0019]    As used throughout the specification and claims, “firearm” means any weapon through which a projectile such as ammunition is fired, such as a pistol, handgun, rifle, carbine, automatic weapon, shotgun, cannon, lank, and the like. 
         [0020]    A schematic of an embodiment of the device is shown in  FIG. 2   a . The device preferably comprises post  10 , which is preferably cylindrical. Barrel  20  may optionally comprise recess  30  for receiving post  10 . Recess  30  does not protrude into the interior of barrel  20  and may be milled, drilled, or otherwise machined. At least a portion of the interior of post  10  is preferably threaded, preferably with 10-32″ threads, for receiving locking bolt  50 . 
         [0021]    Female escutcheon  40  is preferably disposed in the stock so that its bottom surface is flush with the bottom of the stock. Female escutcheon  40  may comprise 4140 Chrome-moly or stainless steel to S.A.A.M.I. specifications, in which case it is preferably inletted or inlayed and spotted into the stock. Female escutcheon  40  may alternately be comprised of a hard wood, such as ebony, which is preferably permanently embedded, for example by gluing, in the forearm. Female escutcheon  40  could then be drilled, countersunk, and shaped when the stock is being shaped prior to finishing. A top view of one embodiment of female escutcheon  40  is shown in  FIG. 2   b . The bottom surface of female escutcheon  40  may be flat, or, as shown in  FIG. 2   c , may optionally be milled or otherwise shaped to form convex radius  65 , or any other shape to complement the stock shape as desired. 
         [0022]    Locking bolt  50  preferably passes through female escutcheon  40  and screws into the interior threads of post  10 , thus securing female escutcheon  40  and the stock (not shown) to post  10  and barrel  20 . The accuracy of the firearm is adjustable by adjusting the tension of locking bolt  50 , which is preferably tightened to approximately 35 ft-lbs. of torque. Locking bolt  50  is preferably the means of attaching the stock to barrel  20  which is located closest to the muzzle. The stock typically prevents barrel  20  from vibrating freely where the two members are contiguous, i.e. along the barrel channel of the stock. Thus in the present invention barrel  20  is preferably free to vibrate approximately from the location of locking boll  50  forward to the firearm muzzle, which permits dampening of the standing waves without interference from the barrel channel inside the stock&#39;s forearm. 
         [0023]    The depth of countersinking of the opening of female escutcheon  40  is preferably chosen so that the head of locking bolt  50  when tightened is flush with the bottom of the forearm; however, the head may optionally protrude or be inset according to the desires of the user. The head of locking bolt  50 , which preferably comprises a 10-32″ threaded bolt but may optionally comprise any type or size of bolt or screw, may be flat and/or comprise a socket for a hex wrench, screwdriver, or the like. The head of locking bolt  50  preferably comprises a protrusion comprising hole  60  for receiving the swivel post of a sling, thus performing a second use as an attachment for a sling swivel. Post  10  and locking bolt  50  are preferably comprised of 4140 Chrome-moly or stainless steel to S.A.A.M.I. specifications. Unlike other designs, preferably no spring is used in the present invention. 
         [0024]    Post  10  may be affixed to firearm barrel  20  using various configurations. As shown in  FIGS. 3   a  and  3   b , post  10  may comprise square head  70  that fits square slot  75 , or dovetail head  80  that fits dovetail slot  85 . In either case, the post can be press fit in place and left as such, or subsequently hard soldered, preferably using 3% nickel soldering rod, or welded in place. As shown in  FIG. 3   c  post  10  can be hard soldered into recess  30 , or may be soldered or welded directly to the exterior of barrel  20  as shown in  FIG. 3   d . As shown in  FIG. 3   e , post  10  may alternately be machined from the barrel blank, which typically starts off with a diameter of 2¼-2½″, when the blank is being milled and/or lathed to produce rifle barrel  20 . For this embodiment post  10  would be integrally formed with barrel  20 . 
         [0025]    In an alternative embodiment, the use of post  10  is optional, or post  10  comprises a cylindrical tube (fully threaded, partially threaded or unthreaded), and recess  30  is threaded. In this embodiment at least a portion of locking bolt  50  screws directly into recess  30 , and optionally additionally screws into post  10  if used. 
         [0026]    In other alternative embodiments, female escutcheon  40  is not used and locking bolt  50  directly holds the stock to barrel  20 , or one or more locking bolts  50  are placed in locations that are not coincident with the stock in order to fine tune the control of the barrel vibrations. 
       EXAMPLE 1 
       [0027]    A .256 Newton custom 98 Mauser rifle equipped with the vibrational stability device of the present invention was test fired by a shooting and ballistics expert using a variety of ammunition at various loads. Referring to  FIG. 2   a , recess  30  was located 8.50″ from the muzzle. Post  10  was 0.375″ in diameter and 500″ long, and comprised a 0.185″ diameter hole with 10-32 TPI threads. Female escutcheon  40  was 9/16″ high, comprised a 1¼×¾″ diamond-shaped top as shown in  FIG. 2   b , and comprised edge  45  which comprised a 6° bevel and was 0.25″ high. Swivel hole  60  was 0.145″ in diameter. Testing showed that there were effectively no signs of high pressure due to the installation of the device, with a maximum case head expansion of 0.002 and only one instance of slightly sticky bolt lift. Bullets of various weights and loads shot monotonously to the same place. Ten shots were fired into two inches using 85, 100, 129, and 140 grain weight bullets in five loads; all but two of the shots fell inside an inch and a half at 100 yards. Thus all but two of the projectiles, which comprised four different weights, landed within 1.5 minutes of angle. This is remarkable accuracy for a series of bullets having multiple weights and loads. 
         [0028]    Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. The dimensions and details disclosed in the example are specific to that example only, and any variations thereof for other embodiments or examples are intended to be covered. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover all such modifications and equivalents. The entire disclosures of all patents and publications cited above are hereby incorporated by reference.