Patent Publication Number: US-8966798-B1

Title: Recoil reducing buffer and stock adaptor for firearms

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation in-part of U.S. patent application Ser. No. 13/950,470, filed Jul. 25, 2013, which claims priority benefit of U.S. Provisional Patent Application No. 61/680,926, filed Aug. 8, 2012, both of which are herein incorporated by reference in their entirety. 
    
    
     FIELD OF USE 
     The invention relates to the field of firearms, specifically firearm accessories, buffer and/or stock adaptors and devices for reducing the recoil of automatic and semi-automatic rifles. 
     BACKGROUND 
     Most modern rifles today are shoulder-mounted, magazine-fed and fire centerfire cartridges. Such rifles may be fully automatic (i.e., fire continuously as long as the trigger is depressed), semi-automatic (i.e., fire only one round per each trigger pull) or bolt action (i.e., require manual reload after each round is fired). While fully automatic and bolt action rifles are primarily employed for combat and hunting applications, respectively, semi-automatic rifles are regularly used by both law enforcement and civilians for hunting, self-defense and sporting applications throughout the United States. 
     HECKLER &amp; KOCH (“H&amp;K”) is a popular manufacturer of high-quality automatic and semi-automatic hunting, sporting and tactical rifles. Because authentic H&amp;K rifles are relatively expensive and widely sought after, a substantial market for H&amp;K “clones” has developed. An H&amp;K “clone” is a non-H&amp;K manufactured firearm made to look and/or function like a firearm manufactured by H&amp;K. Many H&amp;K rifles and their clones (collectively, “H&amp;K-style rifles”) are chambered for such powerful cartridges as the 5.56 mm×45 NATO (the military equivalent to the 0.223 Remington) and the higher-powered 7.62 mm×51 NATO (the military equivalent to the .308 Winchester) rounds. H&amp;K-style rifles also typically use large, heavy bolts that generate significant recoil energy as the bolt travels rearward upon discharge. Accordingly, H&amp;K-style rifles are known throughout the shooting community for having substantially more recoil than other similarly chambered rifles. 
     Recoil (i.e., “kick”) is the backward momentum generated by a firearm when it is discharged. According to Newton&#39;s third law, the recoil generated by discharging a firearm balances the forward momentum of the projectile and exhaust gases expelled during discharge. High-powered cartridges and/or rounds with greater mass produce significantly more recoil energy than low-powered cartridges and/or rounds with less mass. The momentum generated by discharging a shoulder-mounted firearm is transferred to the ground through the body of the shooter and perceived and/or felt by the shooter as recoil. 
     Perceived recoil is the way in which a shooter perceives the recoil of a firearm. Felt recoil is the amount of recoil actually imparted to a shooter by a discharging firearm. Whereas perceived recoil differs between individuals, the felt recoil generated by a particular firearm is quantifiable and constant. 
     Perceived and felt recoil negatively impact a shooter&#39;s experience and performance by degrading accuracy, creating shooter fatigue, and increasing the time needed for reacquisition of a target between shots. For example, a firearm that is said to “kick like a mule” will be approached by a shooter with trepidation because the perceived recoil is high. Such a shooter will flinch in anticipation of the recoil while firing a shot, which can cause the shooter to jerk rather than smoothly squeeze the trigger. Such a jerking motion will disrupt the shooter&#39;s aim. Similarly, a firearm that transfers a large amount of felt recoil to the shooter can reduce the shooter&#39;s control over the firearm and make the firearm unpleasant to shoot. 
     Various mechanisms have been developed to reduce and/or improve felt and perceived recoil. The simplest of these involve the insertion of a lead wedge or other heavy object into one or more cavities in the buttstock of a firearm to increase its overall weight and reduce its momentum during firing. For example, U.S. Patent Application Publication No. 2011/0154707 to Noonan discloses a rifle stock having one or two cylindrical cavities adapted to accept an equal number of similarly sized cylindrical lead bars. While such devices can reduce felt and/or perceived recoil, they add unnecessary weight to the firearm, which can cause a shooter to tire during use. Additionally, these devices often fit the firearm poorly, which can permit the device to dislodge during use and disrupt a shooter&#39;s aim, damage the firearm, and/or cause significant injury. 
     Recoil pads are another type of simple device commonly used to limit recoil. They are typically made of resilient, deformable materials, such as rubber, foam, or leather, and are either attached to the buttstock of a rifle or worn between the buttstock and shoulder of the shooter. Recoil pads reduce perceived and/or felt recoil and prevent slippage of a firearm against a shooter&#39;s clothing by providing an additional layer of recoil-absorbing padding between a rifle&#39;s buttstock surface and the shooter&#39;s shoulder. However, recoil pads do not allow for the use of storage compartments commonly found in many modern synthetic rifle stocks and are not as effective as advanced recoil reducing systems. 
     Many advanced recoil reducing systems use reciprocating parts such as a hydraulic pistons or recoil spring buffer assemblies to dampen recoil. For example, a recoil spring buffer assembly is a mechanism that attaches to a rifle at the rear of the receiver and comprises a tube containing a spring with a plunger-like device (i.e., a buffer) positioned at the end of the spring nearest the receiver or action. The terms “action” and “receiver” and used interchangeably herein. Upon discharge, the rifle bolt travels rearward from the receiver, contacts the buffer and drives the buffer back into the buffer tube, compressing the buffer spring. The opposing force applied to the bolt by the compressing spring slows the momentum of the bolt, thereby reducing the amount of perceived and/or felt recoil imparted to the shooter. Though effective, these types of devices usually require custom gunsmithing to install, are expensive to manufacture, do not lend themselves to mass production, and are not ordinarily interchangeable between different firearms. 
     H&amp;K-style rifles are typically manufactured with removable but non-interchangeable buffer assemblies that are notoriously ineffective at reducing the perceived and/or felt recoil of the rifle model for which they are designed. Specifically, the different models of H&amp;K-style rifles are each equipped with differently sized buffers ranging from the small and light G3 standard buffer to the large and strong HK21E machine gun buffer. Because each model of rifle is designed to accept and function with a buffer of a specific size, H&amp;K-style rifle buffers and their existing U.S.-made clones (collectively, “H&amp;K-style buffers”) are not interchangeable between different rifle models. H&amp;K-style rifles are also incompatible with other more effective and modular recoil spring buffer systems such as the buffer assembly used in the AR-15/M16/M4 and AR-10 rifles (collectively, “AR-style rifles”). 
     AR-style rifles have been used by the U.S. military since the 1960s and are currently one of the more popular style of rifles in the United States. The military success and famous modularity of the AR-style rifle has led to the development of a vast aftermarket for parts and accessories that easily bolt on to existing rifles of various makes. As a result, there are more aftermarket stocks and stock accessories for the AR-15 than any other firearm, including H&amp;K-style rifles. However, AR-style rifle stocks and stock accessories are not compatible with existing H&amp;K-style rifles because AR-style rifle stocks connect to the receiver via the buffer tube component of the rifle&#39;s buffer assembly. 
     Accordingly, there is a need and a demand for a prefabricated, inexpensive and lightweight device that can effectively reduce the amount of perceived and/or felt recoil of an existing H&amp;K-style rifle without the need for custom gunsmithing. There is also a need and desire for a device that can adapt substantially all existing H&amp;K-style rifles to be compatible with the full range of factory and aftermarket AR-style rifle stocks and stock accessories. 
     SUMMARY OF THE INVENTION 
     The present invention provides a prefabricated, lightweight recoil reducing buffer and stock adaptor that attaches to a firearm between the action or receiver and the buttstock. While there are many firearms that may benefit from this invention, the invention is particularly useful with H&amp;K automatic and semi-automatic rifles and their clones. The recoil reducing buffer and stock adaptor of the invention may be machined from any suitably strong material. It is preferably machined from a block of T6 aluminum, steel or titanium. 
     In one aspect, the present invention provides a recoil reducing buffer adaptor that allows an H&amp;K-style rifle to accept and function with a larger and/or stronger H&amp;K-style buffer than the firearm was originally manufactured with, such as the HK21E machine gun buffer. The invention reduces felt and/or perceived recoil and user fatigue, and provides the shooter greater control over the firearm as well as improved reliability and enhanced accuracy by adapting an existing H&amp;K-style rifle to function with a larger and/or stronger H&amp;K-style buffer housed inside an AR-15/M16 buffer tube. In one embodiment, the invention also makes substantially all existing H&amp;K-style rifles compatible with substantially all existing H&amp;K-style buffers, regardless of size. 
     In another aspect, the present invention provides a stock adaptor for H&amp;K-style rifles that allows an H&amp;K-style rifle to accept and function with substantially all currently available factory and aftermarket AR-style rifle stocks and stock accessories. The invention makes substantially all current and existing AR-style rifle stocks and stock accessories compatible with substantially all existing H&amp;K-style rifles by adapting an H&amp;K-style rifle to accept and function with an AR-15/M16 buffer tube. In another embodiment, the invention is also compatible with substantially all existing fixed and telescopic H&amp;K-style rifle stocks. 
     In yet another aspect, the invention provides a method for reducing the recoil of an H&amp;K-style rifle by replacing the original factory buffer of an H&amp;K-style rifle with a larger and/or stronger H&amp;K-style buffer than the rifle was originally manufactured with, installing a recoil reducing buffer and stock adaptor of the present invention into the backplate of the rifle, threading an AR-15/M16 buffer tube into the adaptor to allow the larger and/or stronger H&amp;K-style buffer to extend rearward from the backplate through the buffer tube, and installing a rifle stock over the buffer tube. 
     The invention, together with various embodiments thereof, is more fully explained by the accompanying drawings and the following detailed description thereof. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a rear quartering view of the recoil reducing buffer and stock adaptor of the present invention. 
         FIG. 2  is a rear quartering view of the recoil reducing buffer and stock adaptor of the present invention installed on a synthetic rifle stock. 
         FIG. 3  is a side view of the recoil reducing buffer and stock adaptor of the present invention installed on a synthetic rifle stock. 
         FIG. 4  is a rear quartering view of the recoil reducing buffer and stock adaptor of the present invention installed on an AR-15/M16 buffer tube. 
         FIG. 5  is a front quartering view of the recoil reducing buffer and stock adaptor of the present invention. 
         FIG. 6  is a side view of the recoil reducing buffer and stock adaptor of the present invention assembled with an H&amp;K style rifle backplate and an AR-15/M16 buffer tube. 
         FIG. 7  is a schematic side view of the recoil reducing buffer and stock adaptor of the present invention. 
         FIG. 8  is a schematic rear view of the recoil reducing buffer and stock adaptor of the present invention. 
         FIG. 9  is a schematic front view of the recoil reducing buffer and stock adaptor of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In accordance with the present invention, a recoil reducing buffer and stock adaptor designed to allow an H&amp;K-style rifle to function with a comparatively larger and/or stronger H&amp;K-style buffer than its original factory-installed buffer is provided. The recoil reducing buffer and stock adaptor is a connector that couples the backplate of an H&amp;K-style rifle to a standard AR-15/M16 buffer tube, which is used as a housing for a comparatively larger and/or stronger H&amp;K-style buffer, such as the HK21E machine gun buffer. 
     The adaptor reduces perceived and/or felt recoil and user fatigue, and increases user safety and control over the firearm by adapting an existing H&amp;K-style rifle to accept an AR-15/M16 buffer tube and function with a larger and/or stronger H&amp;K-style buffer housed inside the AR-15/M16 buffer tube. The use of a larger and/or stronger H&amp;K-style buffer provides a greater opposing force on the rifle bolt as it travels rearward during discharge, and thus reduces the amount of perceived and/or felt recoil. 
     By adapting an H&amp;K-style rifle to accept an AR-15/M16 buffer tube, the invention also adapts substantially all existing H&amp;K-style rifles to be compatible with substantially all currently available AR-style rifle stocks and stock accessories. 
       FIG. 1  illustrates a rear quartering view of a recoil reducing buffer and stock adaptor  100  in accordance with the present invention. As shown in  FIG. 1 , the adaptor  100  comprises a top  110 , a bottom  120 , a rear portion  130 , and a front portion  140  opposite the rear portion  130 . The front portion  140  comprises a neck  145  having a narrower profile than the rear portion  130 , the neck  145  being sized and adapted to fit into and engage with a standard backplate of an H&amp;K-style rifle. A buffer port  150  penetrates the adaptor  100  and extends axially through the width of the adaptor  100  at least from the surface of the front portion  140  to the point where the front portion  140  and rear portion  130  of the adaptor meet. In one embodiment, the buffer port extends axially through the adaptor  100  from the surface of the front portion  140  to a depth of approximately 0.50 inches. In another embodiment, the buffer port extends axially through the adaptor  100  from the surface of the front portion  140  to a depth of exactly 0.50 inches. The buffer port  150  is sized and adapted to accept and function with substantially all existing H&amp;K-style rifle buffers, including those manufactured for such H&amp;K-style rifles as the HK21, HK91 and MSG90 models. In one embodiment, the buffer port  150  is approximately 1.00 inches in diameter. In another embodiment, the buffer port  150  is exactly 1.00 inches in diameter. 
     The rear portion  130  of the adaptor is configured with a larger concentric buffer tube aperture  160  situated around the point where the buffer port  150  terminates in the rear portion  130  of the adaptor  100 . The buffer tube aperture  160  is sized and adapted to accept an AR-15/M16 buffer tube. In one embodiment, the buffer tube aperture  160  is approximately 1.148 inches in diameter. In another embodiment, the buffer tube aperture  160  is approximately 1.168 inches in diameter. The buffer tube aperture  160  extends from the exterior surface of the rear portion  130  of the adaptor  100  to a depth corresponding approximately to the point where the rear portion  130  and the front portion  140  of the adaptor  100  meet. In one embodiment, the buffer tube aperture  160  extends to a depth of approximately 0.750 inches. In another embodiment, the buffer tube aperture  160  extends to a depth of exactly 0.750 inches. In preferred embodiments, the buffer tube aperture  160  is threaded to accept an AR-15/M16 buffer tube. In some embodiments, the buffer tube aperture  160  is threaded with Mil-Spec threads to accept a Mil-Spec AR-15/M16 buffer tube. In yet other embodiments, the buffer tube aperture  160  is threaded with Comm-Spec threads to accept a Comm-Spec AR-15/M16 buffer tube. The interior of the buffer tube aperture  160  comprises a flat bottom surface or buffer stop  165  that encircles the buffer port  150  and provides a surface for the buffer tube to abut against. 
     The rear portion  130  of the adaptor is also configured with a recessed area  180  set around the buffer tube aperture  160  that is designed and adapted to accept a retaining collar for holding the adaptor  100  in position on a buffer tube with a locking nut (e.g., a castle nut). Preferably, the retaining collar is configured with one or more detents adapted to engage said locking nut. The upper edge  115  of the rear portion  130  of the adaptor  100  may be beveled or otherwise adapted to simulate the contouring of the upper portion of an H&amp;K-style rifle backplate. This beveled edge  115  adds to the aesthetic appeal of the recoil reducing buffer and stock adaptor  100 , reduces unnecessary weight and ensures that the adaptor  100  will not snag a user&#39;s clothing or gear during use. In one embodiment, the profile of the rear portion  130  of the adaptor  100  substantially matches the profile of the backplate of an H&amp;K-style rifle so that the adaptor  100  appears to be an extension of the backplate when installed on an H&amp;K-style rifle. 
       FIG. 2  illustrates a rear quartering view of the recoil reducing buffer and stock adaptor  200  of the present invention installed on a synthetic rifle stock  290 . The rear portion  230  of the adaptor  200  is oriented toward the rifle stock  290 , while the front portion  240  of the adaptor  200  comprising the neck  245  adapted to fit into and connectively engage with the backplate of an H&amp;K-style firearm is oriented away from the rifle stock  290 . The rifle stock  290  is connected to the adaptor  200  via a buffer tube  292 . The buffer tube  292  is threaded into the buffer tube aperture and held in place by a locking nut  293  engaged with a retaining collar  291  positioned in the recessed area of the rear portion  230  of the adaptor  200 . The beveled edge  215  adapted to simulate the contouring of an H&amp;K-style rifle backplate is shown near the top  210  of the rear portion  230  of the adaptor  200 . 
       FIG. 3  illustrates a side view of the recoil reducing buffer and stock adaptor  300  of the present invention installed on a synthetic rifle stock  390 . A threaded buffer tube  392  connects the adaptor  300  to the rifle stock  390 . As in  FIG. 2 , the buffer tube  392  is threaded into the buffer tube aperture and held in place by a locking nut  393  engaged with a retaining collar  391  positioned in the recessed area of the rear portion  330  of the adaptor  300 . The rifle stock  390  is positioned over and attached to the buffer tube  392  so that the buffer tube extends internally through the stock  390 . In one embodiment, the profile of the rear portion  330  of the adaptor  300  substantially matches the profile of an H&amp;K-style rifle backplate. In another embodiment, the beveled edge  315  near the top  310  of the rear portion  330  simulates the contouring of an H&amp;K-style rifle backplate when the adaptor  300  is installed thereon. 
     The neck  345  of the front portion  340  of the recoil reducing buffer and stock adaptor  300  extends oppositely from the rear portion  330  of the adaptor that engages the buffer tube  392 . The comparatively narrower profile of the neck  345  sized and adapted to fit into and engage with the backplate of an H&amp;K-style rifle is evident near the top  310  and bottom  320  of the adaptor  300 . The front portion  340  of the adaptor  300  is configured with two buffer screw holes  346 ,  347  that index to and align with the buffer screw holes in a standard H&amp;K-style rifle backplate. The upper buffer screw hole  346  is positioned above the buffer port  350  and the lower buffer screw hole  347  is positioned below the buffer port  350 . 
     The recoil reducing buffer and stock adaptor  300  is installed into the backplate of an H&amp;K-style rifle by inserting the neck  345  of the front portion  340  into the backplate of an H&amp;K-style rifle. The adaptor  300  is then secured in place against the backplate by securely threading the rifle&#39;s original or existing buffer screws through the original or existing buffer screw holes in the backplate and into the buffer screw holes  346 ,  347  of the adaptor  300 . 
       FIG. 4  illustrates a rear quartering view of the recoil reducing buffer and stock adaptor  400  of the present invention installed on an AR-15/M16 buffer tube  492 . The buffer tube  492  is threaded into the buffer tube aperture and held in place by a locking nut  493  engaged with a retaining collar  491  positioned in the recessed area of the rear portion  430  of the adaptor  400 . The beveled edge  415  near the top  410  of the rear portion  430  faces toward the buffer tube  492 , while the neck  445  of the front portion  440  sized and adapted to fit into and engage with an H&amp;K-style rifle backplate extends away from the rear portion  430  of the adaptor  400 . The narrower profile of the neck  445  is particularly distinct near the top  410  and bottom  420  of the adaptor  400 . 
       FIG. 5  illustrates a front quartering view of the recoil reducing buffer and stock adaptor  500  of the present invention. The neck  545  of the front portion  540  protrudes from and has a narrower profile than the rear portion  530  of the adaptor  500 . The front portion  540  is configured with two buffer screw holes  546 ,  547  that index to and align with the buffer screw holes native to a standard H&amp;K-style rifle backplate. The upper and lower buffer screw holes  546 ,  547  are positioned longitudinally between the buffer port  550  and the top  510  and bottom  520  of the adaptor  500 , respectively. The comparatively larger inside diameter of the buffer tube aperture  560  is visible through the buffer port  550  extending axially from the surface of the front portion  540  to the point where the front portion and the rear portion  530  of the adaptor  500  meet. In one embodiment, the top  510  of the front portion  540  of the adaptor  500  is also configured with a cavity  548  adapted to accommodate a portion of a recoil spring guide rod rivet or other similar geometry protruding from the rear of an H&amp;K-style rifle backplate so as to allow the adaptor  500  to abut flush against the backplate of an H&amp;K-style rifle when installed. 
       FIG. 6  illustrates a side view of the recoil reducing buffer and stock adaptor  600  of the present invention assembled with an H&amp;K style rifle backplate  648  and an AR-15/M16 buffer tube  692 . The rear portion  630  of the adaptor  600  extends rearward from the backplate  648  opposite a recoil spring and guide rod assembly  649 . The profile of the rear portion  630  of the adaptor  600  substantially matches the profile of the backplate  648 , particularly near the bottom  620  of adaptor, while the beveled edge  615  near the top  610  of the adaptor  600  simulates the contouring of the upper portion of the backplate  648 . The buffer tube  692  extends rearward from the rear portion  630  of the adaptor  600  and is secured in place in the buffer tube aperture by a locking nut  693  engaged with a retaining collar positioned in the recessed area of the rear portion  630  of the adaptor  600 . 
       FIGS. 7 ,  8  and  9  illustrate schematic side, rear and front views, respectively, of the recoil reducing buffer and stock adaptor of the present invention. Dimensions are provided in inches.