Method and device for increasing the rate of the firing cycle of a semi-automatic firearm

A device and method for increasing the rate of the firing cycle of a semi-automatic firearm includes a base that is adapted to support any one of a variety of semi-automatic firearms. The base includes a trigger extension with a grip, a slide mount, and a slide housed within the slide mount. At least the receiver, barrel, and trigger assembly of the firearm are secured to the base so that they may move as a single unit upon the base between a rearward position upon discharge of the firearm and a forward position. A biasing means continuously biases the receiver, barrel, and trigger assembly upon the base toward the forward position to effect successive discharges of the firearm.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to firearms and, more particularly, to a method and device for increasing the rate of the firing cycle of a semi-automatic firearm.

BACKGROUND OF THE INVENTION

Among the differences between automatic firearms and semi-automatic firearms is the rate of their respective firing cycles. Generally, the firing cycle of a semi-automatic firearm involves the sequential steps of depressing the trigger, releasing the trigger, and re-depressing the trigger. Upon discharge, a semi-automatic firearm typically ejects a spent cartridge casing and sequentially feeds a loaded cartridge into the chamber. The “auto-loading” feature of the semi-automatic does not change the fact that a semi-automatic firearm will not discharge without the sequential release and re-depression of the trigger. Hence, the rate of the firing cycle of these firearms is limited by the speed at which the shooter can repeatedly depress, release, and re-depress the trigger.

The firing rate of an automatic firearm, on the other hand, is not. Instead, an automatic firearm will continue to rapidly fire all available rounds in the magazine so long as the trigger remains depressed. When the rate of the firing cycle of the automatic is compared to the firing rate of the semi-automatic, one understands that the firing rate of the semi-automatic firearm is typically limited by the shooter's reaction time; and, even the most proficient shooter cannot discharge more than about one or two rounds per second.

It is important to understand that the National Firearms Act prohibits possession of automatic firearms within the United States, or the District of Columbia, without special authorization. As a result, some innovators have tried to enhance the cyclic firing rate of a semi-automatic firearm to approach the firing rate of the automatic.

Such devices and methods, however, are replete with shortcomings. One such method, like the apparatus shown in U.S. Pat. No. 6,101,918, requires substantial irrevocable modifications to the firearm. The stock is cut out, and a stop member is permanently secured to the stock near the trigger assembly, for example. U.S. Pat. No. 5,074,190 describes another device that has a spring-biased paddle that engages the rear of the trigger and continually urges it forwardly. This device, and others that follow along these lines (U.S. Pat. Nos. 6,164,002, 6,223,644, 5,852,891, 4,803,910, and 4,685,379), require the firearm to be handled in a manner different from a long-arm style. This, and the extreme dexterity typically required to operate these “trigger assemblies” interfere with the accuracy of the shot.

Thus, there remains a need for a device and method that accelerates the rate of the firing cycle of a semi-automatic firearm that does not interfere with the shooter's handling of the firearm and cause him to miss his target. Additionally, there remains a need for such a device and method that does not require extreme dexterity to operate, and that can be used with most any semi-automatic firearm without substantially and irrevocably modifying the firearm. The present invention addresses these needs.

SUMMARY OF THE INVENTION

The present invention relates to a device for increasing the rate of the firing cycle of a semi-automatic firearm that has at least a receiver, a barrel, and a trigger assembly. The device includes a base for supporting the firearm, a trigger extension with a grip attached to the base, and means for removably securing at least the receiver, the barrel, and the trigger assembly to the base. Once secured to the base, the receiver, the barrel, and the trigger assembly are permitted to move as a single unit relative to the base between a rearward position upon discharge of the firearm and a forward position. At least the receiver, barrel, and trigger assembly are continuously biased toward the forward position.

In another aspect, a semi-automatic firearm and device for increasing the rate of the firing cycle of a semi-automatic firearm are presented in combination. The combination includes a receiver, a barrel, a trigger assembly, and a base for supporting the receiver, barrel and trigger assembly. The base also includes a trigger extension with a grip, and means to removably secure the receiver, the barrel and the trigger assembly to the base. In such a combination, the receiver, the barrel and the trigger assembly can move as a single unit relative to the base between a rearward position upon discharge of the firearm and a forward position. The receiver, the barrel and the trigger assembly are continuously biased toward the forward position.

In yet another aspect of the invention, a method for increasing the rate of the firing cycle of a semi-automatic firearm having at least a receiver, a barrel, and a trigger assembly includes the steps of securing at least the receiver, barrel, and trigger assembly of the firearm to a base. Once done, the receiver, the barrel, and the trigger assembly are permitted to move as a single unit relative to the base between a rearward position upon discharge of the firearm and a forward position. Another step includes depressing the trigger with a trigger extension to discharge the firearm. Another step includes immobilizing the trigger extension in the position it has assumed to discharge the firearm. After the firearm discharges, yet another step is to permit the receiver, the barrel, and the trigger assembly to move to the rearward position to effect complete disengagement between the trigger extension and the trigger. Still another step includes sequentially biasing the receiver, the barrel, and the trigger assembly into engagement with the immobilized trigger extension to effect successive discharges of the firearm.

One object of the present invention is to provide an improved device for increasing the rate of the firing cycle of a semi-automatic firearm. Related objects and advantages of the present invention will be apparent from the following description.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purposes of promoting an understanding of the principles of the invention and presenting its currently understood best mode of operation, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, with such alterations and further modifications in the illustrated device and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

FIGS. 1-9relate to a first embodiment of the present invention, a method and device for increasing the rate of the firing cycle of a semi-automatic firearm of the long-arm type configuration. The device includes a base40for supporting at least the receiver22, barrel24, and trigger assembly26of a firearm20. Base40is formed from a rigid material such as steel or the like and includes trigger extension42and grip44, as shown inFIG. 4. It should be understood that base40and its parts may be formed from materials other than steel. Such materials must be rigid and possess the physical and mechanical properties that make them machinable and suitable for supporting the firearms contemplated by the invention. Base40must withstand the forces displaced during discharge of the firearm and during assembly and disassembly, as discussed below.

FIGS. 10-13relate to a second embodiment of the present invention, which relates to a method and device for increasing the rate of the firing cycle of a semi-automatic firearm of the A4 type. Throughout this description, like numerals will be used to identify like parts and features that are common to both of the above-mentioned embodiments.

With reference toFIG. 4, in a currently preferred embodiment, trigger extension42has trigger4, and grip44is a pistol-type grip. The embodiment of base40shown inFIGS. 10 and 11includes trigger extension42having trigger4and pivot128. Trigger4′ has upstanding portion101. Trigger extension42is preferably formed from steel, while grip(s)44,125, as shown inFIGS. 4,10-11, may be formed from wood, plastic or other rigid material.

Referring to all the FIGS., front end41and rear end43of base40are connected by elongated steel members62,64. Base40includes slide50, which is housed in slide mount52. Slide50is presently formed from a material having a low coefficient of friction, such as that sold under the trademark TEFLON. In an embodiment, the front end41of base40includes a set collar65, block58, and a barrel clamp60connected by a cylinder74, as shown inFIG. 4. Barrel clamp60has a removable top portion61and is fastened to base40between collar65and block58. A compression spring59is interposed on cylinder74between barrel clamp60and block58. Barrel clamp60and collar65are held in place on cylinder74by collar screw66. A guide rod69also joins block58and barrel clamp60preventing barrel clamp60from rotating on cylinder74.

With reference toFIG. 5, in a currently preferred embodiment, base40includes legs70, which telescopically engage base40. The leg70oriented toward front end41has ring73.

With reference toFIGS. 1-9, assembly of one combination firearm and device110will be described. Long arm type semi-automatic firearms contemplated by the invention include, for example, the AK-47, AK-74, SKS, Mini 14, M-14, Semi Auto RPD, FAL, M-1 Carbine, Cetme G-3, Daewoo 200, the Smith & Wesson 76 Carbine, and the Ruger AP-9. The AK-47 is used in this disclosure as an example only.

Disassembly of the AK-4720is essentially the same as when cleaning the weapon. With reference toFIG. 3, the magazine30, top cover32, recoil return spring34, and the bolt15and bolt carrier (not shown) are removed by hand. Next, the upper forearm37, gas tube36, and lower forearm38are removed. Bolt 23 frees pistol grip21from receiver22. Care should be taken to isolate and contain pistol grip nut25, which seats in an opening in receiver22. Butt stock screws29are removed, and butt stock27is disengaged from tang31and receiver22.

The barrel24, receiver22, and trigger assembly26are then ready for securing onto base40. Referring toFIGS. 3 and 4, bolt46is removed so that receiver22can be positioned on base40with trigger assembly26inside the U-shaped portion of trigger extension42. Tang31is secured to slide50with slide screws57and barrel24is clamped firmly into clamp60. Clamp60should remain untightened, however, until the receiver22is positioned so that trigger100of trigger assembly26is contacting bolt46. Screws63in top portion61are then firmly tightened to hold barrel24tightly in place.

With reference toFIGS. 7 and 8, the phantom lines show the forward and rearward movement of the barrel24, trigger100and receiver22(in phantom) upon base40during successive discharge of the firearm. In use, a shooter grasps grip44and depresses trigger4of trigger extension42to engage the trigger100and discharge the firearm, as represented inFIG. 7. The shooter holds trigger4of trigger extension42in the depressed position immobilizing trigger extension42in the position it has assumed to discharge the firearm. In response to the firearm's discharge, the receiver22, the barrel24, and the trigger assembly26move to the rearward position to effect complete disengagement of bolt46with trigger100, as shown inFIG. 8.

Compression spring59continuously biases receiver22, barrel24, and trigger assembly26into the forward position (SeeFIG. 7) into engagement with the immobilized trigger extension42so that bolt46, again, re-depresses trigger100to effect successive discharges of firearm20.

It should be understood that the length of elongated members62,64, and thus base40can be configured to suit the length of the particular firearm. Along these same lines, adjustments can also be made to the length of channel56, slide mount52, and slide50(See FIGS.4and10-11), as desired. The free length, and thus tension of compression spring59can also easily be adjusted to accommodate different recoil forces corresponding to various different types of semi-automatic firearms. With the barrel24clamped inside barrel clamp60, set collar screw66is loosened to permit an increase (less tension) or decrease (more tension) of the free length of compression spring59. As a result, the distance between barrel clamp60and block58may be adjusted making base capable of use with most any semi-automatic firearm without substantially and irrevocably modifying the firearm.

The embodiment of base40ofFIG. 4employs a single compression spring59, while the alternate embodiment of base40(FIG. 10) uses a pair of compression springs59. Compression spring59of the embodiment ofFIG. 4is formed from wire having a size range of between about 0.05 and 0.10 inches, a free length range of between about 0.5 and 1.5 inches, and consists of between about 4 and 6 coils. More preferably, compression spring59of the embodiment of base40shown inFIG. 5in combination with the AK-47 is formed from wire having a size of 0.080 inches, a free length of about one inch, and consists of five coils.

In a preferred embodiment, legs70are mounted to base40in tripod fashion, and the forward leg has a ring73so that base40can be secured to the ground surface. This prevents the front end of the device110from raising upward during discharge of the firearm. Base40may be secured to other surfaces by employing any one of a vast number of known means. Once base40is secured to a surface, the firearm can be operated essentially single-handedly. In any event, no “tricky” hand manipulations are necessary to operate device110, and the inventor has found the shooter's shot to be more accurate as a result.

The alternate embodiment of base40(SeeFIGS. 10-11) is designed to support the A4 type semi-automatic firearms. Such firearms may include the reconfigured Browning M1919 A4, the 1917, the M-37, the MG-34, the M-2, and the Semi M-60. It is important to understand that some of these firearms, such as the Browning M1919 A4 for example, are vintage automatic firearms. Additionally, the invention does not contemplate use of such automatic firearms. Instead, the invention contemplates only use of these firearms that have been redesigned and designated as semi-automatic firearms and expressly approved by the Bureau of Alcohol, Tobacco and Firearms (BATF). The Browning M1919 A4 is such a firearm and is used in this disclosure as an example only; it is referred to throughout this description as the A4.

With respect to the assembly of the alternate combination base40and A4 type firearm, the A4 does not have to be disassembled. Referring toFIGS. 10-13, the A4130includes barrel24, receiver22, and a trigger assembly26having a trigger100. Base40shown inFIGS. 10-11has a pair of side-by-side compression springs59. Each spring59is interposed on a cylinder beneath member62,64between bolt mount58′ and trigger mount129. In that embodiment, each spring59is generally formed from wire having a size range of between about 0.03 and 0.080 inches, a free length range of between about 3.0 and 4.0 inches, and consists of between about 20 and 30 coils. More preferably, compression spring59of the embodiment of base40shown inFIGS. 10-11for use in combination with the A-4 is formed from wire having a size of 0.060 inches, a free length of about three and one-half (3.5) inches, and consists of twenty-four coils.

The A4130includes a buffer138with a grip131. The front end of the receiver has a mounting bore133on each side and rings132integrally formed with receiver22. Before securing the A4 to base40, only buffer138is removed. Buffer138is replaced by buffer150(FIG. 13), which has no grip, and is attached to the A4 with bolts135.

To secure the A4 to base40, axel51and bolt112are slidably disengaged and removed from base40. The A4 is positioned above base40so that trigger100of trigger assembly26is contacting trigger4′ in a manner like that described before in connection with the previous embodiment ofFIG. 7. Rings132align with and receive bolt112and mounting bores133align with and receive axle51and thus, A4 is secured to base40, which may include a tripod or other surface-engaging mounting scheme, as previously described.

The A4's barrel24, trigger100and receiver22, therefore, are capable of moving as a single unit upon base40. Slide mount52permits movement of axle51in channel56, in a manner like the above-described embodiment, between a forward and a rearward position during successive discharge of the firearm. In use, a shooter grasps spade grip125with both hands and depresses trigger4of trigger extension42with his thumbs. Trigger extension42pivots at pivot128to engage upstanding portion101, which causes trigger4′ to engage trigger100and discharge the firearm. The shooter holds trigger4of trigger extension42in the depressed position immobilizing trigger4′ of trigger extension42in the position it has assumed to discharge the firearm. In response to the firearm's discharge, the receiver22, the barrel24, and the trigger assembly26move to the rearward position to effect complete disengagement of trigger4′ with trigger100, in a manner like that shown and described above with respect to the embodiment ofFIG. 8.

Compression spring59continuously biases receiver22, barrel24, and trigger assembly26of the A4 toward the forward position into engagement with the immobilized trigger extension42so that trigger4′, again, re-depresses trigger100to effect successive discharges of firearm130.