Gas Key

This application claims the benefit under 35 U.S.C. § 119 (e) (1) of U.S. Provisional Application No. 63/661,696, filed Jun. 19, 2024, which is hereby incorporated by reference in its entirety.

Cycling of a semi-automatic or automatic firearm can use the combustion gases produced during a triggering event of the firearm. A gas tube key can be mounted to the surface of the bolt carrier of the firearm. The gas tube key receives combustion gas from the barrel via a gas tube during the triggering event. Combustion gas entering the bolt carrier from the gas tube key forces the bolt carrier backwards within the upper receiver of the firearm to cycle the action of the firearm.

In some rifles, the bolt carrier may travel approximately 4.5″ backwards during the cycle, as it is forced backwards by the combustion gas. The gas tube key generally becomes separated from the stationary gas tube after approximately 0.75″ of backwards bolt carrier travel. However, combustion gases are still existing from the gas tube after separation from the gas tube key. The resulting gap between the gas tube key and the gas tube can cause combustion gases to be forced into the upper receiver and also into the shooter's face.

Representative implementations of devices and techniques provide novel AR style rifle upper receiver components, including a novel upper receiver, a novel bolt carrier, and a novel gas tube key. The incorporation of a novel gas tube keycomprises novel upper receiver components (i.e., upper receiverand/or bolt carrier) and/or a novel AR styled rifle. The novel gas tube keyis an exact fit for most if not all AR style rifles (e.g., AR-15, M-16, M4, etc.). For instance, the novel gas tube keycan be seamlessly interchanged with the standard gas tube keyof an AR style rifle, and allow the reliable use of the AR style rifle.

In various embodiments, the novel gas tube key (hereinafter “key”) includes a gas tube key extension (hereinafter “extension”) that is integral to the keyor coupled to the key. The extensioncan be coupled to the keyusing various techniques discussed herein. The keywith the extensionhas a length that can be substantially longer than the length of a standard gas tube key, depending on the length of the extension.

In various embodiments, the length of the key(including the length of the extension) can be tuned to determine a gap distance (if any) between the extensionand the gas tubeof the riflewhen the bolt carrieris at its fully retracted state during cycling. Tuning these lengths also tunes the duration of time that there exists a gap (if any) when the bolt carrieris at its fully retracted state. In this way, tuning the overall length of the key(including tuning the length of the extension) can mitigate or eliminate the potential for combustion gases to be forced into the upper receiverand also into the shooter's face during cycling of the rifle.

In various embodiments, the novel gas tube keyincludes different (e.g., greater) interior diameter dimensions at various portions of the key. Changing the interior diameter dimensions of the various portions of the keyallows for tuning the volume of gases moving through the keyas well as tuning the pressure of the gases. In this way, tuning the pressure and volume of gases moving through the key(including tuning the interior diameter dimension of various portions of the key, including the extension) can provide control of cycling of the action while mitigating or eliminating the potential for combustion gases to be forced into the upper receiverand also into the shooter's face during cycling of the rifle.

Referring to, the following part number designations are used throughout for prior art or novel components:

Note that the use of a part number in the discussion (including the drawings) may refer to the part without necessarily indicating whether the part is a novel part or a prior art part. The discussion will provide details regarding novel aspects of the novel parts indicated.

references an example AR style rifle, which is an environment wherein the disclosed techniques and devices may be employed. Referring to, an example AR styled rifle is illustrated, however, the incorporation of novel upper receiver components, such as a novel gas key, a novel bolt carrier, or a novel upper receiver, comprises a novel AR style rifle.

There are tens of millions of common AR styled rifles (including the AR-15, M16, M4, etc.) in America today. With the western-trained allies also using the AR styled rifles, this makes the AR styled rifle one of, if not the most prolific rifle in the world. For instance, this represents a 10 billion dollar per year industry, with most firearms manufacturers around the world producing and/or marketing a version of an AR styled rifle.

AR styled rifles are produced to use various sizes of cartridges, including 0.223/5.56 mm NATO, 0.22-LR, 9×19 mm Parabellum, various shotgun calibers, as well as others, including 7.62×39 mm rounds. The 7.62×39 mm cartridge is a rimless cartridge that was designed by the Soviet Union during World War II for the SKS and AK-47 rifles and others, and has since proliferated throughout the world, being widely used by civilians and militaries nearly everywhere.

Rather than having a single-application receiver as found on some rifles, the AR styled rifles include a modularly designed receiver with separate upperand lowerreceivers. The lower receiverincludes a trigger guard and houses the trigger group. The lower receiveralso includes a means (e.g., screw-type fitting) for coupling the buttstockand a pistol grip. The lower receiveralso includes a magazine wellfor coupling and interchanging various cartridge magazines. The upper receiverattaches to the lower receiverusing front and rear pins. With the rear takedown pin removed, the upper receivercan be pivoted at the front pin location, or it can be removed by removing the front pin.

Referring also to, the upper receiverincludes a couplerfor coupling the barrel, and the handguard. The upper receiveralso houses the bolt carrierwith the boltand the firing pin(see). An ejection portis located at the upper receiverfor expelling spent casings.

Embodiments of riflesare disclosed herein, as embodiments with various novel enhancements. Devices, systems, and techniques are also disclosed herein for enhancing rifles. Accordingly, the devices, systems, and techniques may be integral to a disclosed rifle, or they may be retrofit to a pre-existing rifle (individually or in various combinations).

For example, this document discloses novel upper receiver components, including a novel gas tube key(a.k.a. bolt carrier key). The novel gas tube keyis visually and tactilely differentiable from a common AR style gas tube key, but is operated without the need for specialized training. The novel gas tube keyis assembled to and disassembled from a bolt carrierin a similar way to a standard AR style gas key. However, the shape, size and operation of the novel gas tube keyis distinguishable from a standard gas tube key.

With the novel gas tube keyinstalled at the bolt carrier(forming a novel bolt carrier), the upper receiver assemblyis a direct fit on a standard AR style rifle. The novel gas tube keyis designed for added strength, reliability, safety, and durability. As mentioned, the addition of a novel gas tube keyto a bolt carrier bodycomprises a novel bolt carrier(see). Further, the addition of a novel bolt carrierto an upper receivercomprises a novel upper receiver(see).

Referring to, an example AR style upper receiverassembly is shown. The upper receiverassembly includes a housing for a standard AR style rifle. The upper receiveris constructed to enclose and contain the bolt carrierand related components, and to allow their smooth and reliable movement within the upper receiverduring use.

Referring to, the bolt carrieris constructed to hold the boltand firing pinand related components. The boltis inserted into the front end of the bolt carrierand is held there by the cam pin. When the boltis locked to the barrel extension in preparation for firing, and is rotated and retracted into the bolt carrierby the cam action of the cam pinin the cam pin opening, the cam pinmay bottom out within the cam pin openingof the bolt carrier.

The gas tube keyis mounted to the surface of the bolt carrier, over a gas opening in the bolt carrier(not shown in the drawings). The gas tube keyreceives combustion gases from the barrelvia the gas tubeduring a triggering event. Combustion gas entering the bolt carrierfrom the gas tube keyforces the bolt carrierbackwards within the upper receiverto cycle the action of the rifle.

In some rifles, the bolt carriermay travel approximately 4″ to 4.5″ backwards during the cycle, as it is forced backwards by the combustion gases entering the gas tube key. In some cases, the gas tube keybecomes separated from the stationary gas tubeafter approximately 0.75 inches of backwards travel of the bolt carrier. However, combustion gases are still likely to be exiting the gas tubewhen the gas tube keyis separated from the gas tube. This can be more likely when sub sonic cartridges are used, and with rifles utilizing suppressors that offer back pressure into the system.

The resulting gap between the gas tube keyand the gas tubecan cause combustion/propellant gases to be forced into the upper receiverand also into the shooter's face. This is a timing issue-since the bolt carrieris quickly returned to the forward firing position by the biasing effect (e.g., spring action) from the buffer tube at the buttstock. The forward motion of the bolt carrierreunites the gas tubewith the gas tube keyat the end of the cycle, closing the gap. However, it can be undesirable for combustion gases to be released into the upper receiverand into the shooter's face while the gap is present.

Referring to, a novel gas tube keyis disclosed. The novel gas tube keyreduces the time duration that a gap exists between the gas tube keyand the gas tube, and thereby reduces the time duration and the amount of combustion gas that is released into the upper receiverand into the shooter's face. The novel gas tube keycan also increase a volume of gas moving through the gas tube keyand lower the pressure of the gas. Further, the novel gas tube keycan reduce the debris released into the upper receiverand the shooter's face during a triggering event.

In various embodiments, the novel gas tube keyincludes a key extensionthat reduces the time duration that a gap exists between the gas tube keyand the gas tube. The key extensioncan also be oversized to catch debris during cycling. Further, the interior diameter dimensions of various portions of the novel keycan be increased as compared to a standard gas tube keyto increase volume and lower pressure of combustion gases traversing the gas tube key.

The increased length of the key extensionof the novel gas tube keyfunctions to maintain the connection between the gas tube keyand the gas tubefor a longer duration, thereby containing the propellant gases longer, and reducing the debris released into the upper receiverand into the shooter's face. In some cases, the key extensioncan reduce the time period that the gas tubedumps combustion gases into the upper receiverby ¼ to ½ of the time. In other cases, the time period can be less or greater. In various embodiments, the key extensioncan reduce the distance of separation of the gas tube keyfrom the gas tubefrom about 3″ to about 2″ or less. Accordingly, the key extensioncan reduce the volume of combustion gases escaping the gas tubeduring separation of the gas tube keyfrom the gas tube, and reduce the exposure to the gases.

As shown at, the novel gas tube keycomprises a tube-shaped key bodywith an offset basefor mounting the gas tube keyto the bolt carrier. The offset baseincludes a port or opening(not shown) that is positioned over a like port or opening in the bodyof the bolt carrier. The offset portionof the gas tube keycouples the key bodyto the base, and terminates with the port. There are one or more screw openingsin the basefor securing the gas tube keyin place on the surface of the bolt carrier.

Referring also to, the key extensionis a tube-shaped component that is coupled to or integral with the bodyof the gas tube key. The key extensionincludes a first endthat is configured to mate with the bodyof the gas tube(or is integral to the body) and a second end that comprises a tube portconfigured to slide over and mate with the free end of the gas tube. The key extensionis arranged to mate with the free end of the gas tubewhen the bolt carrieris moved into the forward position in preparation for a triggering event. The key extensionis also arranged to mate with the free end of the gas tubewhen the bolt carrieris pushed forward by the biasing spring within the buttstock, after a triggering event that propels the bolt carrierbackwards.

Referring to, a gas tube keycan be formed with a key extensionas an integral component of the gas tube key. Alternately, as shown at, the key extensioncan be coupled to the end of a specially prepared gas tube keythat has been formed to receive the key extension.

Referring to, the key extensioncan be formed with a first end that comprises a fittingconfigured to mate with the body. In one embodiment, as shown at, the key extensioncan include a fittingconfigured to be pressed into or onto the bodyof the gas tube key. In the embodiment, the bodymay include a recessed portion(e.g., fitting) either on an outer surface of the mating end of the bodyor an inner surface of the mating end of the bodyas applicable to receive the key extension.

In another embodiment, as shown at, the key extensioncan include a threaded fittingconfigured to be screwed into or onto the bodyof the gas tube key. In the embodiment, the bodymay include a threaded portioneither on an outer surface of the mating end of the bodyor an inner surface of the mating end of the bodyas applicable.

In other embodiments, the key extensioncan include a different fittingconfigured to mate with a matching fittingon the key body, or be otherwise configured to be affixed thereon. For instance, the fittingof the key extension may include a bayonet-style coupler, or one of other twist-to-fit couplers. In that case, the fittingof the key bodyincludes a mating bayonet receiver, twist-to-fit receiver, or the like. In any of the above examples, or other examples, coupling the key extensionto the key bodycan be augmented using heat, pressure, cooling, or other means.

The key extensioncan be formed of a hardened steel or other material that is durable and able to withstand high temperatures. The key extensionincludes a tube port(i.e., opening) that is configured (i.e., size and shape) to receive the end of the gas tubeduring cycling. In some cases, the portmay be enlarged in diameter to capture debris being expelled from the gas tube. In other cases, the entire key extensionmay be enlarged in diameter to capture debris and to increase the volume of gas traversing the key.

The key extensioncomprises a tube that can be between 0.5″ and 1.0″ in length. In alternate embodiments, the key extensionmay be shorter or longer. The length of the key extensiondetermines the length of the resulting gap between the key extensionand the gas tubeduring cycling of the action and the corresponding time duration that a gap between the gas tube keyand the gas tubeis present. Thus, the length of the gap and the time duration of the gap can be tuned by using extensionsof different lengths. A key extensionwith a greater length results in a shorter gap duration, and vice versa. In an embodiment, a length of the key extensionis proportional to a predetermined time duration for the gap during cycling of the action of the firearm. Thus a particular length of key extensioncan be used to achieve a predetermined gap time and/or gap distance.

In one illustrative example, the cycle time of a common AR styled rifle is between 0.1 and 0.2 seconds for one complete cycle. In the example, the bolt carriermoves 4″ backward, followed by 4″ forward during one cycle. After 0.5″ of backward movement, or about ⅛ portion of the backward travel, a standard gas keyseparates from the gas tube, forming a gap. Combustion gases are still exiting the gas tube, at least during this first backward portion of the cycle. That means that during the remaining ⅞ portion of backward travel, or about 3.5″ and 0.044 to 0.088 seconds, combustion gases and debris are entering the upper receiverand being propelled into the shooter's face.

The gap remains between the gas tube keyand the gas tubethrough another ⅞ portion of the forward travel, which includes 3.5″ and another 0.044 to 0.088 seconds, for a total gap time of between 0.088 to 0.176 seconds. In some cases, gases and debris may continue to be expelled from the gas tubethrough at least part of the forward portion of the cycle.

The addition of the key extensionto the gas tube keyreduces the duration that a gap between the gas tube keyand the gas tubeis present, as well as reducing the gap distance itself. For example, the end of the gas tuberemains within the gas tube key, or the key extension, for a longer duration than with a prior art gas tube keyalone. Considering the example above, the addition of a 1″ key extensionto a gas keymeans that the backward travel gap time is reduced to about 0.031 to 0.0625 seconds, and the total gap time is reduced to between 0.0625 to 0.125 seconds. This significant reduction can be further tuned by applying gas key extensionsof predetermined lengths, as discussed herein.

Referring to, the gas tube keyand its constituent portions (,,) can be further tuned by enlarging an interior diameter of one or more of the portions (,,). The illustrations ofshow two examples of using predetermined interior dimensions A, B, and C with a gas keyto tune the key. Tuning the keycan be performed relative to using various types of ammunition with different charges and combustion characteristics. In each case, desired goals can include a reduction (or minimizing) of combustion gas expelled into the upper receiverpaired with a desired boltcycle that is reliable and predictable. Using (or tuning) novel gas keyswith different dimensions, including different lengths of key extensionand various interior diameter dimensions at various portions of the keywith the various types of ammunition can lead to achieving the desired goals.

For instance, a predetermined keywith specific dimensions can be paired with specific ammunition to be used in the rifle. In some cases, the dimensions of an existing gas key (or) installed on a bolt carriermay be designed to work with ammunition that was used in the past, but will not be used with the rifle going forward. In other cases, the combustion gases of a desired type of ammunition to be used with the riflemay not be fully utilized with the existing gas key (or).

Replacing the gas key (or) with a different gas keyhaving different predetermined dimensions, can improve or maintain the cycle performance of the bolt carrier, while reducing the gas and debris expelled into the upper receiverand into the shooter's face. Replacing the gas key (or) on the bolt carrieris a simple matter of unscrewing the baseof the existing gas key (or) from the bolt carrier, and attaching the baseof the replacement gas keyto the bolt carrier. The fit of the various gas keys (or) is the same, since the gas keys (or) are interchangeable.

Referring to, the interior diameter dimension “C” of the offset portioncan be enlarged on a novel keyto reduce the restriction to gas flow and increase the volume of gas traversing through the keyto the bolt carrier. Increasing the volume of gas traversing through the keylowers the pressure of the traversing gas, while maintaining the cycling functionality. The interior diameter dimension “B” of the key bodycan remain as in a stock configuration, or it can be adjusted up or down as desired to tune the volume and pressure of the gas traversing through the key.

Further, the diameter “A” of the extensioncan also be enlarged to tune the volume and pressure of the gas traversing through the key, as well as to capture a greater volume of the debris being expelled from the gas tubeduring a greater portion of the boltcycle. A greater volume of gas captured and/or moving through the keycan translate to a greater volume of gas that is functioning to cycle the action of the rifle, and a lesser volume of gas and debris that is available to be expelled into the upper receiverand into the shooter's face. Accordingly, the interior diameter dimension “A” may be greater than the interior diameter dimension “B” or the interior diameter dimension “C”.

Various increments of the interior dimensions A, B, and C can be made when a gas keyis formed, so that gas keyshaving any desired dimensions can be available. In other words, gas keyswith various combinations of different dimensions A, B, and C can be formed and used to tune bolt carriers, upper receivers, and riflesas desired. Any and all gas keyswith the various dimension combinations can include extensionsof various lengths as well, providing fully customizable performance.

Although various implementations and examples are discussed herein, further implementations and examples may be possible by combining the features and elements of individual implementations and examples.

Although the implementations of the disclosure have been described in language specific to structural features and/or methodological acts, it is to be understood that the implementations are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as representative forms of implementing the claims.