FIREARM UPPER RECEIVER

TECHNICAL FIELD

The present disclosure relates generally to firearm upper receivers, and more particularly to a magnesium alloy upper receiver for use in firearms including the AR-10, AR-15, M-16, and variants thereof.

BACKGROUND

The ArmaLite AR-10 was developed by Eugene Stoner in the late 1950s as a lightweight assault rifle for military use. The basic AR-10 design had a direct impingement, rotating bolt configured to accept 7.62×51 mm NATO (.308 Winchester) cartridges. In 1957, the AR-10 design was rescaled and substantially modified by ArmaLite to accommodate 5.56×45 mm NATO (.223 Remington) cartridges, and given the designation AR-15. ArmaLite sold its patent rights to the AR-10 and AR-15 to Colt Firearms in 1959. After subsequent modifications, the AR-15 was adopted by the US military as the M-16 rifle. With the expiration of the ArmaLite patents in 1977, other manufacturers began producing their own variants of the firearm, commonly known as AR-15 style rifles.

Today, the AR-15 rifle has become one of the most beloved rifles in the United States, and has been referred to as “America's rifle” by the National Rifle Association (NRA). One innovative feature of the AR-15 rifle is its distinctive two-part upper and lower receiver and its modular design enabling ease in the interchangeability and replacement of parts. As civilian ownership of AR-15 style rifles grew, numerous manufacturers began producing “improved” aftermarket modules, assemblies, or parts with features not found on factory rifles. Due to the modular construction of AR-15 rifles, individuals with an average mechanical aptitude can substitute aftermarket parts with the original factory parts to customize their rifle. Due to the vast assortment of aftermarket parts and accessories currently on the market, the AR-15 style rifle has been referred to as the “Swiss Army knife of rifles.”

FIG. 1 depicts a partial cross-sectional view of an AR-15 rifle 100 generally including an upper receiver group 102, lower receiver group 104, stock 106, and barrel 108. The upper receiver group 102 can generally be seen as the upper half of the rifle 100. The upper receiver group 102 can include a bolt carrier group 110, charging handle 112, ejection port dust cover (not depicted), forward assist (not depicted), and the upper receiver housing 114 which encapsulates and combines these components. The upper receiver housing 114 can have a flat top with a picatinny rail 116 or it can have a carry handle (not depicted).

The lower receiver group 104 contains all of the parts needed to fire the rifle 100, such as a trigger group 118, magazine well 120, and grip 122. According to the laws of many countries, the lower receiver 102 is the part of the rifle 100 that is considered to be the firearm itself (rather than just a component), and therefore typically carries the serial number of the firearm 100. The lower receiver group 104 is typically joined to the upper receiver group 102 with two takedown pins 124A-B. The stock 106 is attached to the rear end of the lower receiver group 104. The barrel 108 is attached to the front end of the housing 114 of the upper receiver group 102.

The upper receiver housing 114 (referred to hereinafter as the “upper receiver” or “upper”) is generally considered an interchangeable component of the firearm 100, as it does not carry the serial number of the firearm 100. Presently, a variety of upper receivers 114 are commercially available. In general, the upper receivers 114 currently available on the market are designed to accommodate barrels of different weights, lengths and calibers. As AR-15 rifles are commonly carried for long distances and durations by police, hunters and sportsmen, a desire exists to lighten or otherwise reduce the overall weight of the upper receiver 114.

The present disclosure addresses this concern.

SUMMARY OF THE DISCLOSURE

As discussed in various forums, past efforts have been made to construct an upper receiver out of a lightweight magnesium metal alloy; however, such efforts have been met with little success, as to date no magnesium metal alloy has been found that can withstand the heat, pressure and frictional forces generated from cycling the rifle 100 over an appreciable duration (e.g., functional usage for at least 500 firearm actuation cycles). As a result, to the extent that any magnesium uppers have been produced, durability has been a major concern.

Embodiments of the present disclosure provide lightweight, corrosion and abrasion resistant magnesium firearm upper receivers, configured to lighten or otherwise reduce the overall weight of AR-10 rifles, AR-15 rifles, M-16 rifles and variants thereof, while ensuring a functional life of at least 500 firearm actuation cycles, and in many cases more than 10,000 firearm actuation cycles. Various apparatus embodiments and methods of manufacturing magnesium upper receivers are disclosed herein.

One embodiment of the present disclosure provides a firearm upper receiver including a magnesium alloy housing defining an upper receiver cavity having an interior surface shaped and sized to enable actuation of a bolt carrier group therein during a firearm actuation cycle, wherein at least a portion of the interior surface is coated with a hardened anodized coating configured to slow operational wear on the interior surface generated by heat, pressure and frictional forces during a firearm actuation cycle to ensure a functional life of the magnesium alloy housing over at least 500 actuation cycles.

In one embodiment, the hardened anodized coating includes a magnesium-oxide layer. In one embodiment, the magnesium-oxide layer includes one or more hardening agents embedded therein. In one embodiment, the hardened anodized coating is treated with a topcoat surface treatment. In one embodiment, the topcoat surface treatment is at least one of an electrophoretic paint and/or lubricity enhancing agent.

In one embodiment, the firearm upper receiver further includes a brass deflector. In one embodiment, the brass deflector is constructed of a material other than magnesium alloy. In one embodiment, the brass deflector is positionable relative to the magnesium alloy housing within a deflector channel defined by the magnesium alloy housing. In one embodiment, the brass deflector includes a deflecting surface configured to impart directional control on brass ejected from the magnesium alloy housing during firearm actuation.

Another embodiment of the present disclosure provides a method of making a firearm upper receiver, including: machining a housing including an upper receiver cavity out of a stock of extruded magnesium alloy; and applying a hardened anodized coating to at least a portion of an interior surface of the upper receiver cavity to slow operational wear on the interior surface generated by heat, pressure and frictional forces during a firearm actuation cycle to ensure a functional life of the housing over at least 500 firearm actuation cycles.

Another embodiment of the present disclosure provides a firearm upper receiver kit including a magnesium alloy housing defining an upper receiver cavity having an interior surface coated with a hardened anodized coating configured to slow operational wear on the interior surface generated by heat, pressure and frictional forces during a firearm actuation cycle, and one or more brass deflector including a deflecting surface configured to impart directional control on brass ejected from the magnesium alloy housing during firearm actuation.

The summary above is not intended to describe each illustrated embodiment or every implementation of the present disclosure. The figures and the detailed description that follow more particularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be more completely understood in consideration of the following detailed description of various embodiments of the disclosure, in connection with the accompanying drawings, in which:

FIG. 1 is a partial, cross-sectional, perspective view depicting an AR-15 rifle.

FIG. 2A is a perspective view of a magnesium alloy upper receiver, in accordance with an embodiment of the disclosure.

FIG. 2B is a right side view depicting the magnesium alloy upper receiver of FIG. 2A.

FIG. 2C is a top view depicting the magnesium alloy upper receiver of FIG. 2A.

FIG. 2D is a left side view depicting the magnesium alloy upper receiver of FIG. 2A.

FIG. 2E is a bottom view depicting the magnesium alloy upper receiver of FIG. 2A.

FIG. 2F is a proximal end view depicting the magnesium alloy upper receiver of FIG. 2A.

FIG. 2G is a distal end view depicting the magnesium alloy upper receiver of FIG. 2A.

FIG. 2H is a bottom perspective view depicting the magnesium alloy upper receiver of FIG. 2A, including details of the upper receiver cavity in accordance with an embodiment of the disclosure.

FIG. 3 is a schematic diagram depicting a system for applying an anodized coating to an upper receiver, in accordance with an embodiment of the disclosure.

FIG. 4 is a flowchart depicting a method of making an upper receiver, in accordance with an embodiment of the disclosure.

FIG. 5 is a perspective view depicting ejection of brass from a magnesium alloy upper receiver, in accordance with an embodiment of the disclosure.

FIG. 6A is a plan view depicting a brass deflector, in accordance with a first embodiment of the disclosure.

FIG. 6B is a plan view depicting a brass deflector, in accordance with a second embodiment of the disclosure.

FIG. 6C is a plan view depicting a brass deflector, in accordance with a third embodiment of the disclosure.

FIG. 7 is a perspective view depicting a brass deflector, in accordance with a fourth embodiment of the disclosure.

FIG. 8 is a perspective view depicting an upper receiver having a quick release ejection port dust cover, in accordance with an embodiment of the disclosure.

FIG. 9 is a perspective view depicting an ejection port dust cover, in accordance with an embodiment of the disclosure.

FIG. 10A is a close-up, cross-sectional view depicting a portion of an ejection port dust cover including a pin in a first, outwardly extending position, in accordance with an embodiment of the disclosure.

FIG. 10B is a close-up, cross-sectional view depicting the portion of the ejection port dust cover including the pin in a second, retracted position, in accordance with an embodiment of the disclosure.

FIG. 11A is an exploded, perspective view depicting an indexing pin and indexing pin sheath of a barrel assembly, in accordance with an embodiment of the disclosure.

FIG. 11B is a perspective view depicting the assembled indexing pin and indexing pin sheath of the barrel assembly of FIG. 11A.

FIG. 12A is a perspective view depicting an indexing pin, in accordance with a first embodiment of the disclosure.

FIG. 12B is a perspective view depicting the indexing pin of FIG. 12A positioned on a barrel assembly, in accordance with an embodiment of the disclosure.

FIG. 13A is a perspective view depicting an indexing pin, in accordance with a second embodiment of the disclosure.

FIG. 13B is a perspective view depicting the indexing pin of FIG. 13A included as part of a barrel assembly, in accordance with an embodiment of the disclosure.

FIG. 14A is a perspective view depicting an indexing pin, in accordance with a third embodiment of the disclosure.

FIG. 14B is a perspective view depicting the indexing pin of FIG. 14A included as part of a barrel assembly, in accordance with an embodiment of the disclosure.

FIG. 15A is a perspective view depicting an indexing pin, in accordance with a fourth embodiment of the disclosure.

FIG. 15B is a perspective view depicting the indexing pin of FIG. 15A included as part of a barrel assembly, in accordance with an embodiment of the disclosure.

While embodiments of the disclosure are amenable to various modifications and alternative forms, specifics thereof shown by way of example in the drawings will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims.

DETAILED DESCRIPTION

Referring to FIGS. 2A-H, a magnesium alloy upper receiver housing 150 (hereinafter referred to as an “upper receiver” or “upper”), is depicted in accordance with an embodiment of the disclosure. It should be appreciated that the terms “AR-15,” “firearm,” “upper receiver” and “upper” are used for basic explanation and understanding of the operation of the systems, methods and apparatuses of this disclosure. Therefore the terms “AR-15,” “firearm,” “upper receiver” and “upper” are not to be construed as limiting the systems, methods, and apparatuses of this disclosure, and are to be understood broadly to include any firearm having a blowback operated system.

Generally, the upper receiver 150 can include a, right side wall 152, top wall 154, left side wall 156, and a bottom wall 158. In some embodiments, the right, top, left, and bottom walls 152, 154, 156, and 158 can be included as sides in a general octagonal cross-sectional configuration. Additionally, it should be appreciated that, depending on the desired configuration of the upper receiver 150, the right side wall 152 and the left side wall 156 can be alternated so that the left side wall 156 becomes the right side wall 152, and the right side wall 152 becomes the left side wall 156. The right, top, left and bottom walls 152, 154, 156, and 158 can generally extend between a proximal end 160 and a distal end 162. FIGS. 2B-G respectively depict the right side, top, left side, bottom, proximal end, and distal end views of the upper receiver 150.

In one embodiment, the right, top, left and bottom walls 152, 154, 156, and 158 can define an upper receiver cavity 164. The cavity 164 can generally extend from a charging handle aperture 166 and bolt aperture 168 (located in proximity to the proximal end 160) to a gas tube aperture 170 and barrel aperture 172 (located in proximity to the distal end 162). The charging handle aperture 166 can generally be aligned along a longitudinal axis of the upper receiver 150 with the gas tube aperture 170. Likewise, the bolt aperture 168 can generally be aligned along the longitudinal axis of the upper receiver 150 with the barrel aperture 172. In some embodiments, the upper receiver 150 can include barrel nut threading 173 on the distal end 162 to enable coupling of the upper receiver 150 to a barrel. In some embodiments, the barrel nut threading 173 can define an indexing notch 193 configured to receive a corresponding indexing pin of a barrel assembly, thereby inhibiting the barrel assembly from rotating relative to the upper receiver housing 150 when the upper receiver housing 150 and barrel assembly are operably coupled to one another, for example via a barrel nut threaded on to barrel nut threading 173.

An ejection port aperture 174 and a forward assist aperture 176 (depicted in FIG. 2F) can be formed in the right side wall 152 of the upper receiver 150. In some embodiments, the right side wall 152 can define a pair of ejection port dust cover retention slots 175A/B, configured to receive a dust cover (as described in further detail below). A forward assist cover 178 can extend outwardly from the right side wall 152 to define the forward assist aperture 176. In one embodiment, a forward assist fastener aperture 179 can be formed through the right side wall 152 and/or a portion of the forward assist cover 178. In some embodiments, the right side wall 152 can further define a brass deflector channel 188, configured to receive a brass deflector (as described in further detail below).

Depending upon the configuration, a carry handle (not depicted) or picatinny rail portion 182 can be formed along the top wall 154 of the upper receiver 150. A pivot pin lug 184 and take down pin lug 186 can extend from the bottom wall 158 of the upper receiver 150, thereby enabling the upper receiver 150 to be operably coupled to a lower receiver.

With reference to FIG. 2H, the right, top, left, and bottom walls 152, 154, 156, and 158 defining the upper receiver cavity 164, can further define a cutout 165 and ramp 167. During operation, the cutout 165 can be configured to receive a portion of a bolt carrier group (specifically a cam pin head). The ramp 167, which can extend proximally from the cutout 165, can define a shallow angled slope (e.g., an angle of between about 0.25° and about 10°) to provide a gradual transition between a surface 169 generally parallel to a longitudinal axis of the upper receiver 150 and the cutout 165, thereby promoting smoother cycling of the bolt carrier group, and reducing frictional wear on interior surfaces of the upper receiver cavity 164.

It should be appreciated that a more detailed explanation of other components of the upper receiver 150, instructions regarding how to attach and use the various components of the upper receiver 150, methods for installing related components of the upper receiver 150, and certain other items and/or techniques necessary for the implementation and/or operation of various components of the AR-15 platform are not provided herein because such background information is known to one of ordinary skill in the art. Therefore, it is believed that the level of description provided herein is sufficient to enable one of ordinary skill in the art to understand and practice the systems, methods and/or apparatuses as described herein.

In one embodiment, the upper receiver 150, including the right, top, left and bottom walls 152, 154, 156, and 158, can be constructed of a high-strength, lightweight metal alloy, such as magnesium; although other alloys, such as aluminum, titanium and steel can also be used. For example, in one embodiment, the upper receiver 150 can be machined from a high-strength, extruded stock of magnesium alloy having an extruded cross-section shape near the net shape of the finished upper receiver 150.

For example, in one embodiment, an extruded rail of magnesium alloy can have an octagonally shaped cross-section generally defining the right, top, left and bottom walls 152, 154, 156, and 158 of the upper receiver 150. Thereafter, the extruded rail can be machined to define the various features of the upper receiver 150, including, for example, the upper receiver cavity 164, charging handle aperture 166, gas tube aperture 170, ejection port aperture 174, forward assist aperture 176, picatinny rail 182, pivot pin lug 184, take down pin lug 186, and/or other features and/or components. In one embodiment, approximately 70% of an exterior of the finished upper receiver 150 is machined, while the remaining approximate 30% of the exterior remains as in un-machined state, so as to have previously been defined by the extruded rail of magnesium alloy stock. In another embodiment, portions of the upper receiver 150 can be forged.

Magnesium which is approximately 33% lighter than aluminum, 60% lighter than titanium, and 75% lighter than steel has readily apparent weight advantages over other materials in the construction of an upper receiver 150, with similar strength characteristics to other construction materials. However, magnesium alloys are considered less stable and more prone to corrosion and/or electrolysis in comparison to other alloys, particularly in the presence of saltwater. Accordingly, despite the significant reduction in weight, if not properly cared for, components constructed of magnesium alloys may have a shorter lifespan than components constructed of more stable, corrosion and wear resistant materials.

A rapid breakdown of the upper receiver 150 constructed of a magnesium alloy can be exacerbated by the heat and pressure experienced within the upper receiver cavity 164 during operation, as well as the high frictional sliding force of the bolt carrier group each time the rifle is cycled, particularly as magnesium alloys are generally found to be softer than other metals, such as aluminum alloys. Accordingly, durability continues to be a major concern in the construction of an upper receiver 150 out of a magnesium alloy. In fact, conventional wisdom suggests that it is not possible to construct an upper receiver 150 out of a magnesium alloy with a usable lifetime or duration that justifies the expense of creating such an upper receiver 150.

Applicants of the present disclosure have discovered a solution to this problem through the application of a highly wear resistant, anodized coating to one or more surfaces of the magnesium alloy upper receiver 150. Accordingly, upper receivers 150 of the present disclosure are able to withstand the heat and pressure experienced within the upper receiver cavity, as well as the high frictional sliding force of the bolt carrier group during sustained operations, even when exposed to a variety of harsh environmental conditions (e.g., exposure to saltwater).

In one embodiment, the anodized coating is applied to the upper receiver 150 by generally immersing the machined upper receiver 150 in an electrochemical bath containing a chemical slurry. The chemical slurry can be formed of an aqueous electrolytic solution having a pH of at least 12.5, and comprising between about 2 g/L and about 12 g/L of an aqueous soluble hydroxide, between about 2 g/L and about 15 g/L of a fluoride containing composition selected from the group consisting of fluorides and fluorosilicates, and between about 5 g/L and about 30 g/L of silicate or between about 5 g/L and about 30 g/L of vanadate. In one embodiment, one or more physical property modifying agents can be added to the chemical slurry. The one or more physical property modifying agents can be configured to improve surface hardness, increase surface lubricity, modify the color, increase electrical conductivity, and the like.

For example, in one embodiment, one or more surface hardening agents, such as zinc oxide (ZnO), micro-sized industrial diamond particles (e.g., particles of C having a size of between about 0.1 and about 100 μm), nano-sized industrial garnet particles (e.g., particles of A₃B₂Si₃O₁₂having a size of between about 1 nm and about 100 nm), silicon carbide (SiC), and/or aluminum oxide (Al₂O₃), can be added to the chemical slurry to increase the surface hardness and improve abrasion resistance of the upper receiver 150. In one embodiment, one or more surface lubricity agents, such as micro-sized Teflon™ spheres ((C₂F₄)_n) and/or a solid lubricant, such as molybdenum disulfide (MoS₂), can be added to the chemical slurry to increase the surface lubricity of the upper receiver 150. In one embodiment, agents configured to modify the color of the anodized coating, agents to improve the electrical conductivity of the anodized coating, as well as other agents to modify or improve the physical properties of the anodized coating can be added to the chemical slurry. In one embodiment, the one or more physical property modifying agents or combinations thereof can be added to the chemical slurry in the amount of between about 1 g/L and about 150 g/L.

Referring to FIG. 3, a schematic diagram depicting a system 200 for applying an anodized coating to an upper receiver 150 is depicted in accordance with an embodiment of the disclosure. Prior to applying the anodized coating, the upper receiver 150 can optionally be pretreated to degrease or cleanse the surface of the upper receiver 150 and/or to create a desirable base over at least a portion of the surface of the upper receiver 150. In other embodiments, the upper receiver 150 can be immersed in the chemical slurry 202 without preconditioning.

While immersed in the slurry 202, an electrical potential and/or current can be applied to the upper receiver 150 via a rectifier 204. In one embodiment, the rectifier 204, which can be in electrical communication with a voltage source 206, can be configured to produce a wave signal configured to drive the anodized coating process. In one embodiment, the rectifier 204 can have an output voltage potential of between about 150 volts and about 360 volts; although other output voltages of the rectifier 204 are also contemplated.

To apply the electrical potential and/or current across the upper receiver 150, an anode 208 in electrical communication with the rectifier 204 can be placed in electrical communication with the upper receiver 150 (such that the upper receiver 150 effectively becomes the anode 208). A cathode 210, also in electrical communication with the rectifier 204 can be placed elsewhere within the chemical slurry 202, so as to create an electrical potential between the cathode 210 and the upper receiver 150 through at least a portion of the slurry 202, such that the upper receiver 150 generally has a positive charge. In another configuration, the position of the anode 208 and the cathode 210 can be reversed, such that the upper receiver 150 generally has a negative charge.

During the anodized coating process, the slurry 202 can be agitated or circulated within the electrochemical bath 212, such that the slurry 202 (which can be a heterogeneous mixture) remains in suspension. In one embodiment, a magnetic stir plate can be utilized to agitate the slurry 202 within the electrochemical bath 212. In other embodiments, the slurry 202 can be circulated via a pump 214. Such a configuration can be particularly useful where certain components of the slurry 202 have a tendency to settle at the bottom of the electrochemical bath 212 during the anodized coating process. Accordingly, the pump 214 can continuously pull a quantity of slurry 202 through one or more outlets or drains 216, and reintroduce the quantity of slurry 202 into the electrochemical bath 212 through one or more inlets or jets 218, thereby inhibiting separation of the slurry 202. In one embodiment, the pump 214 can serve to pressurize the slurry 202, such that reintroduction of the slurry 202 into the electrochemical bath 212 occurs under force. In one embodiment, the one or more inlets 218 can be formed as nozzles configured to improve agitation and overall mixing of the slurry 202.

In one embodiment, the pump 214 can further be configured to route a quantity of slurry 202 through a heat exchanger 220, which can be in communication with a heat sump 222. The heat exchanger 220 and heat sump 222 can be configured to maintain the slurry at a desired temperature, or at least partially control or slow a natural increase in the slurry 202 temperature during the anodized coating process. For example, in one embodiment, the slurry 202 can be maintained at a temperature of between about 2° C. and about 20° C. over the course of the anodized coating process; although other temperatures of the slurry 202 are also contemplated. In an alternative embodiment, a heat exchanger or chiller (for example in the form of a coil) can be positioned directly within the electrochemical bath 212; particularly where a magnetic stir plate is utilized to agitate the slurry 202.

Accordingly, the above described anodized coating results in the growth of an oxide layer over the surface of the upper receiver 150. The growth results in an irregular porous ceramic-like magnesium-oxide layer from the magnesium with the effect of improving or altering hardness, abrasion resistance, surface lubricity, color and/or electrical conductivity of the upper receiver 150. In some embodiments, the entire upper receiver 150 can be submerged in the chemical slurry 202. In other embodiments, anodized coating of the upper receiver 150 can be limited to specific surfaces, such as the upper receiver cavity 164 or other areas subject to repetitive wear, heat, pressure and/or abrasion.

In addition to providing superior hardness, abrasion resistance and surface lubricity to the upper receiver, thereby enabling an extended product life, the porous nature of the anodized coating can additionally serve as a base, offering excellent adhesion for an optional surface treatment. Accordingly, in some embodiments, the upper receiver 150 can be coated with a topcoat surface treatment, such as paint and/or a lubricity enhancing sealant or agent. For example, in one embodiment, the upper receiver 150 can be sealed via an electrophoretic painting process (E-Coat), and/or one or more layers of an applied solid film lubricant, Teflon®, and/or Cerakote® ceramic coating. Other surface coating treatments are also contemplated.

Referring to FIG. 4, a method 300 of making an upper receiver 150 is depicted in accordance with an embodiment of the disclosure. At 302, a section of magnesium alloy extrusion stock can be machined to define the various features of the upper receiver 150. For example, in one embodiment, the magnesium alloy extrusion stock can be machined to define an upper receiver cavity 164, charging handle aperture 166, gas tube aperture 170, ejection port aperture 174, forward assist aperture 176, picatinny rail 182, pivot pin lug 184, take down pin lug 186, and/or other features and/or components of the upper receiver 150. In one embodiment, approximately 70% of the surface of the magnesium alloy stock can be machined to define the various features of the upper receiver 150. In another embodiment, portions of the upper receiver 150 can be forged.

At 304, an anodized coating can be applied to one or more surfaces of the machined upper receiver 150. For example, in one embodiment, the machined upper receiver 150 can be immersed in a chemical slurry 202 while an electrical potential is applied to the upper receiver 150 to drive the anodized coating process. In some embodiments, the anodized coating can include one or more surface hardening agents, one or more surface lubricity agents, and/or one or more physical property modifying agents. In some embodiments, the upper receiver 150 can optionally be pretreated to degrease or cleanse the surface of the upper receiver 150 prior to immersing the upper receiver 150 in the chemical slurry 202.

At 306, the upper receiver 150 can optionally be coated with a topcoat surface treatment, such as a paint and/or lubricity enhancing agent. Accordingly, embodiments of the present disclosure provide a method of constructing a lightweight upper receiver 150 out of a magnesium alloy having a hardened surface that enables the upper receiver 150 to withstand the high temperatures, pressures, and frictional sliding forces present within the upper receiver group of a semi-automatic firearm, particularly those present within the upper receiver cavity 164.

It should be understood that the individual steps used in the methods of the present teachings may be performed in any order and/or simultaneously, as long as the teaching remains operable. Furthermore, it should be understood that the apparatus and methods of the present teachings can include any number, or all, of the described embodiments, as long as the teaching remains operable.

In addition to the upper receiver cavity 164, another area of the upper receiver 150 particularly prone to wear is the brass deflector 180. With reference to FIG. 5, during operation of the rifle 100, spent shell casings 126 (frequently referred to as “brass”) ejected from the upper receiver cavity 164 impact the brass deflector 180, which serves to generally direct the ejected brass 126 along an ejection trajectory 128. In some embodiments, to inhibit wear from repeated impact with ejected brass 126, the brass deflector 180 can be constructed of a material other than a magnesium alloy, such as steel, aluminum, plastic, and/or resin; although construction of a brass deflector 180 out of a magnesium alloy having a hardened anodized coating is also contemplated.

With reference to FIG. 6A, in some embodiments, the upper receiver 150 can be machined to include a brass deflector channel 188, into which the brass deflector 180 can be slidably positioned. For example, in one embodiment, the brass deflector channel 188 can be configured as a dovetail groove extending proximally from the ejection port aperture 174. Accordingly, the brass deflector 180, having a brass deflecting surface 190, can be slidably positioned within the brass deflector channel 188. In one embodiment, the brass deflector 180 can be fixed in position relative to the upper receiver 150 via a set screw 192. Accordingly, the deflecting surface 190 can be configured to generally direct the ejected brass 126 along the ejection trajectory 128.

In some embodiments, it may be desirable to tailor or modify the trajectory 128 of the ejected brass 126; particularly, when it is desirable to restrict ejection of the brass 126 to a direction or area, for example when firing in close proximity to other individuals or tight quarters. Accordingly, as depicted in FIG. 6B, in one embodiment, an angle □ (e.g., between about 20° and about 90°) of the deflection surface 190A of the brass deflector 180 can be increased or decreased as desired to modify the trajectory 128 of the ejected brass 126. As depicted in FIG. 6C, in yet another embodiment, the deflection surface 190B can include an arc or curve, as desired to modify the trajectory 128 of the ejected brass 126. Other angles and contours of deflection surface 190 to modify the trajectory 128 of the ejected brass 126 are also contemplated.

In some embodiments, the upper receiver 150 can be sold as a kit including several brass deflectors 180, each having a deflection surface 190 specifically tailored to direct the ejected brass 126 along a desirable trajectory 128. For example, in one embodiment, a first brass deflector 180 can be configured to direct the brass 126 along a traditional ejection trajectory 128, a second brass deflector 180 can be configured to direct the ejected brass 126 towards the ground and/or feet of the user in a rapid manner, and a third brass deflector 180 can be configured to direct ejected brass 126 over a shoulder of the user. Other desirable ejection trajectories are also contemplated.

With reference to FIG. 7, in yet another embodiment, the brass deflector 180 can be configured to be adjusted by the user to modify the trajectory 128 of the ejected brass 126. For example, in one embodiment, brass deflector 180 can include a base 194 an adjustable member 196 including a deflecting surface 190, and a fastener 198. In operation, the base 194 can be operably coupled to the upper receiver 150, for example, slidably received within the deflector channel 188. The adjustable member 196 can be rotated as desired to achieve the desired ejection trajectory 128, and secured in a fixed position relative to the base 194 via fastener 198. Thereafter, adjustments to the ejection trajectory 128 can be accomplished via loosening the fastener 198 and moving the base 194 forward or aft within the deflector channel 188 and/or rotating the adjustable member 196 relative to the base 194.

With reference to FIG. 8, a further improvement to the upper receiver 150 can include a quick release ejection port dust cover 177, configured to selectively pivot between a first position, in which the ejection port aperture 174 is covered (as depicted in FIG. 8) to inhibit dust and debris from entering the ejection port aperture 174, and a second position, in which the ejection port aperture 174 is uncovered thereby enabling the ejection of brass therefrom.

Upper receivers of AR-15 type firearms typically include an ejection port dust cover. Such dust covers often break or have some other type of malfunction, requiring removal and replacement. However, removal and replacement of a conventional dust cover is generally considered to be a difficult process, often requiring the removal of the barrel from the upper receiver in order to remove a pivot pin running the length of the dust cover, which serves to pivotably retain the dust cover with respect to the upper receiver.

The quick release ejection port dust cover 177 of the present disclosure addresses this problem through replacement of the single, long pivot pin with a pair of opposed, outwardly biased pins 179A/B configured to extend at least partially into the ejection port dust cover retention slots 175A/B defined by the upper receiver 150, thereby promoting the ease in removal of the ejection port cover 177 from the upper receiver 150, and without the need to remove the barrel or other components from the upper receiver 150. An additional advantage of this feature is that the ejection port dust cover retention slots 175A/B are more easily machined than the aperture required for a pivot pin running the length of the dust cover with conventional dust covers, thereby presenting a time and cost savings in the manufacture of the upper receiver 150. For example, in some embodiments, the dust cover retention slots 175A/B can be machined with a “lollipop” bit, as opposed to the drilling of a 3 inch long, ⅛ inch diameter aperture, as is required to accommodate the longer pivot pins of conventional dust covers.

With reference to FIG. 9, in one embodiment, the dust cover 177 can include a panel 181 configured to selectively cover the ejection port aperture 174. The panel 181 can be constructed of any suitable rigid material, such as metal, polymer, or composite. In one embodiment, the panel 181 can define one or more channel 183 running lengthwise along one edge of the panel 181 and configured to receive the pins 179A/B and a spring retention rod 185. The spring retention rod 185 can be configured to retain a biasing member 187 in position relative to the panel 181, the biasing member 187 configured to bias the dust cover 177 to the second, open position when operably coupled to the upper receiver 150. In some embodiments, the panel 181 can further include a latch 189 configured to selectively retain the dust cover 177 in the first, closed position relative to the upper receiver 150.

FIG. 10A depicts a close-up, cross-sectional view of one of the pins 179A in a first, outwardly extending position, while FIG. 10B depicts the pin 179A in a second, retracted position. As depicted, a biasing member 191 can be positioned between a portion of the pin 179A and the panel 181, thereby naturally biasing the pin 179A to the first, outwardly extending position, and in a manner which naturally retains a pivotable connection between the dust cover 177 and the upper receiver 150 (as depicted by FIG. 8). When removal of the dust cover 177 is desired, a user can insert a small rigid object (e.g., the tip of the screwdriver, pen, or toothpick) into either of the retention slots 175A/B to force the pin 179A/B to the second, retracted position, thereby enabling removal of the dust cover 177 from the upper receiver 150.

As previously described, in some embodiments, the barrel nut threading 173 can define an indexing notch 193 (as depicted in FIG. 2A) configured to receive a corresponding indexing pin of a barrel assembly. Referring to FIG. 11A, an indexing pin 195 of a barrel assembly 201 is depicted in accordance with an embodiment of the disclosure. Capture of the indexing pin 195 of the barrel assembly 201 within the indexing notch 193 of the upper receiver 150 can serve to inhibit the barrel assembly 201 from rotating relative to the upper receiver 150 during assembly. Misalignment of the barrel assembly 201 and upper receiver 150 can result in impingement of actuatable firing components which partially extend into the barrel assembly (e.g., an extractor) during operation of the firearm. In some circumstances, the impingement can result in the firearm “jamming” or failing to cycle properly. Misalignment may also (either directly or indirectly) interfere with accuracy, as the gun sights may not be properly oriented with respected to the intended trajectory of the bullet.

In some cases, when a torque is applied to the barrel assembly 201 (e.g., during assembly or attachment of threaded connections to the muzzle), the sole element inhibiting the barrel assembly 201 from rotating relative to the upper receiver 150 is the indexing pin 195. Where the force and/or pressure between the indexing pin 195 and the notch 193 exceed the material properties of the upper receiver 150 and/or barrel assembly 201, permanent deformation to the components can occur. The use of softer materials (e.g., fabrication of the upper receiver 150 out of a magnesium alloy) can exacerbate this problem.

Applicants of the present disclosure have addressed this problem by developing an indexing pin 195 and/or indexing pin sheath 203 configured to disburse the force over a larger surface area (thereby reducing the pressure experienced between the notch 193 and indexing pin 195). For example, with reference to FIGS. 11A-B, in one embodiment an indexing pin sheath 203 can be applied to an existing (standard sized) indexing pin 195. In embodiments, the indexing pin sheath 203 can include a planar surface 205 configured to increase the surface area contact with the indexing notch 193, thereby disbursing the force experienced as a result of torque applied to the barrel assembly 201 over a larger area of the notch 193.

In other embodiments, the indexing pin 195 and sheath 203 can be configured as a single, unitary component intended to replace an existing indexing pin 195. For example with reference to FIGS. 12A-B, a replacement indexing pin 207 is depicted in accordance with an embodiment of the disclosure. In such an embodiment, the replacement indexing pin 207 can include a substantially round post portion 209 configured to fit within a predefined aperture within the barrel assembly 201 (e.g., the aperture from which the indexing pin 195 is removed), and a polygonal upper portion 211 having a planar surface 205 configured to increase the surface area contact with the indexing notch 193. In some embodiments, the polygonal upper portion 211 can generally assume the shape of a square, rectangle, or other polygon. In other embodiments, the upper portion 211 can have an elliptical, irregular or other than polygonal shape, which in some embodiments can be keyed to the notch 193 of the upper receiver 150 to inadvertent inhibit rotation. In some embodiments, the corners of the upper portion 211 can be filleted which can contribute to ease in insertion of the indexing pin 207 into the notch 193 during assembly of the barrel assembly 201 to the upper receiver 150.

As depicted in FIGS. 13A-14B, in other embodiments, the replacement indexing pin 207′ and 207″ can be a polygonal or elliptical plug configured to be received within a correspondingly shaped aperture 213 defined in the barrel assembly 201. As depicted in FIGS. 15A-B, in yet other embodiments, the barrel assembly 201 can define a notch 215 into which the replacement indexing pin or key 207′″ can be received. In some embodiments, the indexing pin 207 (or sheath 203) can be constructed of a suitable, compatible material such as a steel, aluminum or magnesium alloy. In some embodiments, the indexing pin 207 (or sheath 203) can be constructed of a material configured to absorb stress or shock to further inhibit permanent damage or deformation to the upper receiver 150 when a torque is applied to the barrel assembly 201.

Various embodiments of systems, devices, and methods have been described herein. These embodiments are given only by way of example and are not intended to limit the scope of the claimed inventions. It should be appreciated, moreover, that the various features of the embodiments that have been described may be combined in various ways to produce numerous additional embodiments. Moreover, while various materials, dimensions, shapes, configurations and locations, etc. have been described for use with disclosed embodiments, others besides those disclosed may be utilized without exceeding the scope of the claimed inventions.

Persons of ordinary skill in the relevant arts will recognize that the subject matter hereof may comprise fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not meant to be an exhaustive presentation of the ways in which the various features of the subject matter hereof may be combined. Accordingly, the embodiments are not mutually exclusive combinations of features; rather, the various embodiments can comprise a combination of different individual features selected from different individual embodiments, as understood by persons of ordinary skill in the art. Moreover, elements described with respect to one embodiment can be implemented in other embodiments even when not described in such embodiments unless otherwise noted.

Although a dependent claim may refer in the claims to a specific combination with one or more other claims, other embodiments can also include a combination of the dependent claim with the subject matter of each other dependent claim or a combination of one or more features with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a specific combination is not intended.

Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. Any incorporation by reference of documents above is further limited such that no claims included in the documents are incorporated by reference herein. Any incorporation by reference of documents above is yet further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein.

For purposes of interpreting the claims, it is expressly intended that the provisions of 35 U.S.C. § 112(f) are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.

Number	Date	Country
62910985	Oct 2019	US
62963844	Jan 2020	US
63058318	Jul 2020	US

FIREARM UPPER RECEIVER

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