Patent Application
20240003644
The present invention relates, generally, to AR-15 type rifles and, more particularly, to a trigger guard for those rifles having a lower receivers which conform to military specifications for the M-16 automatic rifle.
An assault rifle is a gas-operated rifle designed for combat that can be selectively fired in both fully-automatic and semi-automatic modes. Assault rifles are the standard infantry weapons in most modern armies, having largely superseded or supplemented larger and more powerful battle rifles such as the M14, FN FAL and the Heckler & Koch G3. Examples of assault rifles include the AK-47, the M16, the M4 and the Steyr AUG.
The German military developed the assault rifle concept during World War II, based upon research that showed that most firefights happen at a range of less than 300 meters. The power and range of contemporary rifle cartridges was excessive for most small arms firefights. As a result, the German military sought a cartridge and rifle combining submachine gun features (large-capacity magazine, selective-fire) with an intermediate-power cartridge effective to 300 meters. To reduce manufacturing costs, the 7.92×57 mm Mauser cartridge case was shortened, the result of which was the lighter 7.92×33 mm Kurz (short). The Sturmgewehr model 1944 (storm rifle model 1944, usually abbreviated StG 44), is generally considered by historians to be the first modern assault rifle. Developed in Nazi Germany toward the end of World War II, it was the first of its kind to see major deployment. Though derided by the allied forces for its heavy receiver and fully-automatic fire capability, the StG44 fulfilled its role admirably, particularly on the Eastern Front, by offering greatly-increased concentration of fire, as compared to standard infantry rifles then in use. Fortunately, it arrived too late to have a significant effect on the outcome of the war.
Mikhail Kalashnikov began his career as a weapon designer while in a hospital after being wounded during the rout of Soviet troops by the German forces at the Battle of Bryansk. While recovering from his injuries, Kalashnikov experienced repeated flashbacks of the battle, and became obsessed with creating a submachine gun that would drive the Germans from his homeland. After tinkering with a sub-machine gun design for some time, he entered a 1944 competition for a new weapon that would chamber the 7.62×41 mm cartridge developed by Elisarov and Semin in 1943. A particular requirement of the competition was that the firearm be serviceable and reliable in the muddy, wet, and frozen conditions of the Soviet frontline. The Kalashnikov entry—a carbine bearing a strong design resemblance to the American M1 Garand—lost out to a Simonov design that would later become the SKS semi-automatic carbine. However, in response to a subsequent design competition in 1946, Kalashnikov and his design team submitted a redesign of his original carbine. The gas-operated rifle which his team entered is most aptly described as a hybrid of the best rifle technology of the period. His design incorporated the trigger, double locking lugs and unlocking raceway of the M1 Garand/M1 carbine; the safety mechanism of the Browning-designed Remington Model 8 rifle; and the gas system and layout of the StG44. Sixty years after its acceptance by the Soviet military in 1947, the iconic Avtomat Kalashnikova Model 1947 (shortened to AK-47) remains the most widely-used assault rifle in the world. More AK-type rifles have been produced than all other assault rifles combined. The main advantages of the Kalashnikov rifle are its simple design, fairly compact size and adaptability to mass production. It is inexpensive to manufacture, and easy to clean and maintain. In addition, its ruggedness and reliability are legendary. The large gas piston, generous clearances between moving parts, and tapered cartridge case design allow the gun to endure large amounts of foreign matter and fouling without failing to cycle. However, this reliability comes at the cost of accuracy, as the looser tolerances do not allow for precision and consistency.
The M14 rifle is an American selective-fire automatic rifle that chambers 7.62×51 mm NATO ammunition. It was the standard issue US rifle until 1970. The M14 was used for US Army and Marine Corps basic and advanced individual training, and was the standard issue infantry rifle in CONUS, Europe, and South Korea, until replaced by the M16 rifle in 1970. It remains in limited front line service with the United States Army, Marine Corps, Navy, and Air Force, and remains in use as a ceremonial weapon. It was the last so-called “battle rifle” (a term applied to weapons firing full-power rifle ammunition) issued in quantity to U.S. troops. The M14 was developed from a long line of experimental weapons based upon the M1 Garand, the first successful semi-automatic rifle to be put into active military service. Designed by Canadian-born John C. Garand while employed as a consulting engineer by the U.S. Springfield Armory, the M1 was standard issue for U.S. soldiers during World War II. Though among the most advanced infantry rifles of the 1940s, it was not a perfect weapon. It primary detractions were its length, its mass, its heavy ammunition, and its lack of a fully-automatic mode. Toward the end of the war, modifications were made to the basic design which addressed the final detraction. Those modifications included the incorporation of fully-automatic firing capability and replacing the 8-round “en bloc” clips with a detachable box magazine holding 20 rounds. John Garand's T20 conversion was the most widely-used of the fully-auto M1 variants. However, it soon became evident that the size and weight attributes of the basic M1 design required a more radical approach. Earle Harvey and Lloyd Corbett, both employees of the Springfield Armory, were instrumental in designing rifles for the new 0.30 Light Rifle cartridge, which was based upon 0.30-06 cartridge case cut down to the length of the 0.300 Savage case. The 0.30 Light Rifle eventually evolved into the 7.62×51 mm NATO and the commercial .308 Winchester round. Although shorter than the 0.30-06, the 7.62×51 mm NATO round retained the same power due to the use of modern propellants. Harvey was instrumental in designing a completely new T25 rifle prototype, while Corbett was tasked with developing 0.30 Light Rifle conversions of the M1 and T20 designs. Corbett's original T44 prototype used a T20 receiver rebarreled for the NATO 7.62 mm round. In addition, the long operating rod/piston of the M1 was replaced with the T25's shorter “gas expansion and cut-off” system. The T44 design evolved to use newly-fabricated receivers that were shorter than those of either the M1 or T20. The new action's length was matched to the shorter 7.62 mm NATO cartridge instead of the longer 0.30-06. Corbett's more conservative approach ultimately prevailed during design competitions that began in 1954, and the T44 was adopted by the U.S. military as the M14 in 1957. Springfield Armory began tooling a new production line in 1958 and delivered the first service rifles to the U.S. Army in July 1959.
Acceptance of the M14 did not occur before a radical newcomer entered the contest. In 1954, Eugene M. Stoner became chief engineer of newly-formed ArmaLite, a division of Fairchild Engine & Airplane Corporation. Stoner was primarily responsible for the development of the 7.62 mm AR-10. Springfield's T44 and similar entries were conventional rifles that used wood for the buttstock and which were built entirely of steel using mostly forged and machined parts. ArmaLite was founded specifically to bring the latest in designs and alloys to firearms design, and Stoner felt he could easily beat the other offerings. Stoner's AR-10 was radical for its day. The receiver was made of forged and milled aluminum alloy instead of steel. The barrel was mated to the receiver by a separate hardened steel extension to which the bolt locked. This allowed a lightweight aluminum receiver to be used while still maintaining a steel-on-steel lockup. Whereas on traditional semi-automatic rifles, the action is actuated by a cylinder and piston close to a gas vent in the barrel, the bolt on the AR-10 was operated by high-pressure combustion gases taken from a hole in the middle of the barrel, routed directly through a tube above the barrel to a cylinder, with the bolt carrier itself acting as a piston. On the AR-10, the stock and grips were made of a glass-reinforced plastic shell over a rigid foam plastic core. The muzzle brake was fabricated from titanium. The layout of the weapon itself was also somewhat unique. Previous designs generally placed the sights directly on the barrel, using a bend in the stock to align the sights at eye level while transferring the recoil down to the shoulder. This meant that the weapon tended to rise when fired making it very difficult to control during fully-automatic fire. The ArmaLite team used a solution previously used on weapons such as the German FG 42 and Johnson light machine gun; the barrel was in line with the stock, well below eye level, with the sights to eye level. The rear sight was built into a carrying handle over the receiver. The AR-10 was a very advanced design for its time. Despite being over 2 lb (0.9 kg) lighter than the competition, it offered significantly greater accuracy and recoil control. Two prototype rifles were delivered to the U.S. Army's Springfield Armory for testing late in 1956. At this time, the U.S. armed forces were already two years into a service rifle evaluation program, and the AR-10 was a newcomer with respect to older, more fully-developed designs. Unfortunately, ArmaLite's president, George Sullivan, insisted that both prototypes be fitted with barrels made of aluminum extruded over a thin stainless steel liner. Shortly after the aluminum-steel composite barrel burst on one of the prototypes in 1957, the AR-10 was rejected. However, later that same year, General Willard G. Wyman, commander of the U.S. Continental Army Command (CONARC) put together a team to develop a .223 caliber (5.56 mm) weapon. Wyman had seen the AR-10 in an earlier demonstration and, impressed by its performance, personally suggested that ArmaLite enter an AR-10 modified to use a 5.56 mm cartridge designed by Winchester. ArmaLite commissioned Stoner's chief assistant, Robert Fremont, and Jim Sullivan, another employee, with the task of scaling down the basic AR-10 design to fire the small-caliber .223 Winchester cartridge. When improper assembly of the prototypes being tested resulted in CONRAC rejecting the design, Fairchild, which had already spent $1.45 million in development costs with no potential return on the investment, decided to bail out of the small-arms business. Fairchild thereafter sold production rights for the AR-15 to Colt Firearms in December 1959, for a mere $75,000 in cash and a 4.5% royalty on subsequent sales. In 1960, ArmaLite was reorganized, and Stoner left the company. Given such an inauspicious beginning, it would have been difficult to predict that within five years, the AR-15 would be adopted by United States military forces as the M16 rifle, and that it and variants thereof would be in continuous production well into the twenty-first century.
The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 made by ArmaLite. It is a shorter and lighter version of the M16A2 assault rifle, achieving 80% parts commonality with the M16A2. The M4 has selective fire options including semi-automatic and three-round burst (like the M16A2), while the M4A1 has a “full auto” option in place of the three-round burst.
The AR-15 and M16 rifle designs are derived from the AR-10. As on the AR-10, the bolt on the AR-15 and M16 is operated by high-pressure combustion gases taken from a hole in the middle of the barrel. The gases are routed directly through a tube above the barrel to the front of the bolt carrier, which acts as a piston. The bolt and bolt carrier slide within a receiver extension, which functions as a cylinder. The bolt and bolt carrier slide backwards against a buffer that is inserted in the front end of an action spring that is installed within the receiver extension. The receiver extension, incidentally, is housed within the rifle's buttstock. As the bolt, bolt carrier and buffer slide backwards, the rifle's hammer is reset as an extractor simultaneously pulls the spent casing from the chamber. Once the casing is clear of the chamber, an ejector kicks the casing out of the receiver. The AR-15, M16 and derivative rifles are, thus, gas operated via a method known as direct impingement (DI). The DI system has the advantage of having the absolute minimum of recoiling action parts, resulting in the minimum possible weapon disturbance due to balance shifting during the action cycle as well as reducing overall weapon weight. It has the disadvantage of the propellant gas (and the accompanying fouling) being blown directly into the action parts. DI operation increases the amount of heat that is deposited in the receiver while firing, which can burn off essential lubricants. Lack of proper lubrication is the most common source of weapon stoppages or jams. The bolt, extractor, ejector, pins, and springs are also heated by this high-temperature gas. These combined factors reduce service life of these parts, reliability, and mean time between failures.
On the AR-15, the extractor and the rifle's firing pin are integral parts of the bolt. As the action spring 102 is compressed, rearward travel of the bolt, bolt carrier and buffer slows to a stop and immediately reverses. During forward movement of the bolt, bolt carrier and buffer, the bolt strips a fresh cartridge from the rifle's magazine and pushes it into the chamber. As soon as the trigger is squeezed, the hammer slams into the firing pin, which is concentrically mounted within the bolt, thereby beginning the action process anew.
Many members of the U.S. Democratic Party would like to ban all handguns and all rifles not specifically designed for sporting (hunting) use. Such a ban would mirror those already in effect in many European nations. On Sep. 13, 1994, following a close 52-48 vote in the US Senate, an “assault weapon” ban was signed into law by President Bill Clinton on the same day. The ban applied only to weapons manufactured after the date of the ban's enactment. It expired on Sep. 13, 2004, in accordance with its sunset provision. Several constitutional challenges were filed against provisions of the ban, but all were rejected by the courts. There were multiple attempts to renew the ban, but none succeeded. Under the Assault Weapons Ban of 1994, the definition of “assault weapon” included specific semi-automatic firearm models by name, and other semi-automatic firearms that possessed two or more features from a specified feature set:
The law also categorically banned the following makes and models of semi-automatic firearms and any copies or duplicates of them, in any caliber:
Studies have shown the ban had little effect on overall criminal activity, firearm homicides, and the lethality of gun crimes, although there is tentative evidence that the frequency of mass shootings may have decreased slightly while the ban was in effect.
The State of California enacted an assault weapons ban that mirrors the 1994 federal ban. On Jun. 4, 2021, US District Judge Roger Benitez of San Diego, ruled that the California assault weapons ban violates the Second Amendment's right to bear arms and deprives Californians from owning assault-style weapons commonly allowed in other states. Benitez issued a permanent injunction Friday so the law cannot be enforced. In his ruling, Benitez stated: “Like the Swiss Army Knife, the popular AR-15 rifle is a perfect combination of home defense weapon and homeland defense equipment. Firearms deemed as ‘assault weapons’ are fairly ordinary, popular, modern rifles.” Subsequently, on Jun. 21, 2021, a three-judge panel on the US 9th Circuit Court of Appeals issued a stay of US District Judge Roger Benitez's order. Thus, California's 1989 ban on assault weapons laws remains in effect while further proceedings continue.
Gun control advocates, as well as gun rights advocates have referred to at least some of the features outlined in the federal Assault Weapon Ban of 1994 as merely cosmetic. The inclusion in the list of features that were purely cosmetic in nature created a loophole that allowed manufacturers to successfully circumvent the law by making minor modifications to the weapons they already produced. One such “cosmetic feature” is the definition of a pistol grip. If the webbing of the hand between the thumb and forefinger is below the exposed top of the trigger when grip is held with the hand and the trigger is pulled with the index finger of the same hand, then the grip is, by definition, a pistol grip. If the webbing of the hand is above the exposed top of the trigger, it is, again by definition, not a pistol grip.
The present invention provides a trigger guard for military-specification lower receivers of AR-15 rifles, which converts a standard pistol grip to a legal non-pistol grip by lowering the exposed top of the trigger to such an extent that the webbing of the hand between the thumb and forefinger is above the exposed top of the trigger when the grip is held with the hand and the trigger is pulled with the index finger of the same hand. Some non-military-specification AR-15 rifles have a trigger guard that is incorporated in the lower receiver; in other words, the trigger guard is cast as part of the lower receiver. The present invention is not compatible with such rifles.
The invention will now be described with reference to the attached drawing figures. It should be understood that the drawings were drawn to scale, as nearly as possible. Nevertheless, they are intended to be merely illustrative of the invention.
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The trigger guard 1100 is secured at the front of the trigger recess 105 with a spring loaded pin (not shown) and at the rear of the trigger recess 105 with a push pin 1001 in a conventional manner. Trigger guard 1100 is not the preferred embodiment of the invention for the simple reason that there are slight variations in dimensions of the trigger recess 105, even on lower receivers that comply with the basic dimensions of military specifications. Thus, each alternative embodiment trigger guard 1100 might need to be filed or otherwise machined to fit a particular trigger recess 105, whereas the preferred embodiment trigger guard 200 can flex somewhat to accommodate variances in measurements within the trigger recess 105. The alternative embodiment trigger guard 1100 has an annular format, with a spacer portion 1101 interconnected to a lower portion 1102 via an anterior link portion 1103 and an aft link portion 1104, all of which are integral components of the alternative embodiment trigger guard 1100. The lower portion 1102 is similar to the lower portion 201 of the preferred embodiment trigger guard 200, in that it has a front aperture 1105 and a rear aperture 1106, which enable the alternative embodiment trigger guard 1100 to be secured at the front of the trigger recess 105 with a spring-loaded pin (not shown) which snaps into the front aperture 1105, and at the rear of the trigger recess 105 with a push pin 107, which passes through the rear aperture 1106, within the lower receiver 102.
This application claims priority based on the filing of Provisional Patent Application No. 63/314,620 on Feb. 28, 2022.
| Number | Date | Country | |
|---|---|---|---|
| 63314620 | Feb 2022 | US |
