The present disclosure generally relates to firearm reliability, and more particularly to firearm reliability systems including a charging handle insert and a variable bolt weight assembly.
Various factors can affect firearm reliability. For example, a firing cycle for a firearm, such as an AR-15, may be affected by the cyclic rate, i.e., how fast the bolt opens and closes after a shot is fired. If the cyclic rate is too fast, the action may jam the magazine, the extractor may lose its grip on the rim, or the bolt may catch the casing before it can eject. If it is too slow, there may not be enough force to extract the casing or it may not open far enough to eject a fired casing. There also may inconsistent seating (and positioning) of the chamber adapter relative to the rifle's chamber and/or bouncing of the chamber adapter assembly during firing. Further, casings can get caught in the charging handle.
Embodiments of the present disclosure may provide a firearm reliability system comprising: a charging handle insert (CHI) that may increase cycling reliability by preventing rimfire casings from getting caught in a charging handle and deflecting gas away from a shooter during firing; and a variable bolt weight assembly (VBWA) that may slip under a spring guide rod extension of a bolt assembly and contact a back of a bolt. The VBWA may contact the back of the bolt near a firing pin and/or may contact the back of the bolt on a keyed area on a back of the spring guide rod extension. The system may be used with a dedicated rimfire firearm. The system may be used with a centerfire firearm with a chamber adapter style rimfire conversion kit installed, and the CHI may fill a gas key channel in a centerfire charging handle (CCH) to prevent malfunctions from empty rimfire casings that become lodged in the gas key channel. The system also may include a buffer pressure plug that may increase cycling reliability by applying steady forward pressure to a back plate of a rimfire bolt carrier, bolt, and chamber adapter assembly; and a buffer spring, wherein the buffer pressure plug may compress the buffer spring to add extra pressure to the back plate of the rimfire bolt carrier, bolt, and chamber adapter assembly. The buffer pressure plug may include a retention slot in which a buffer pin rests to keep the buffer pressure plug aligned; and an insertion slot disposed along a length of a cylinder of the buffer pressure plug, the insertion aligned with the buffer pin and pushed straight rearward to insert. The system also may include a bolt buffer including a hole that may receive a spring guide rod and a tab that may interface with a cutout on the back plate of the rimfire bolt carrier, bolt, and chamber adapter assembly. The system may further include a modified collar that may lock a chamber adapter into the modified collar, thereby allowing a dedicated rimfire group to be used in a centerfire gun through the chamber adapter that may be inserted and locked in and removed for use in a dedicated rimfire rifle. The system also may include a polymer buffer that may serve as a bolt impact point, the polymer buffer including tabs that may slide into corresponding grooves on a collar, wherein the polymer buffer may eliminate noise of metal-on-metal between the bolt and the collar.
Other embodiments of the present disclosure may provide a firearm reliability system comprising: a charging handle insert (CHI) that may increase cycling reliability by preventing rimfire casings from getting caught in a charging handle and deflecting gas away from a shooter during firing, the CCH comprising: a semi-cylindrical lower profile that may match a semi-cylindrical profile of a gas key channel of a charging handle; gas deflection cutouts that may redirect gas from an open gas tube and block an open channel leading back toward a shooter; and a center channel that may retain the CHI inside of a plurality of charging handle types. The CHI may further comprise retention ramps on either side of the center channel to enhance friction between the CHI and walls of the gas key channel of the charging handle. In a conversion kit configuration in a centerfire rifle, a gas tube may connect to a rifle's bore forward of a chamber and interface a centerfire bolt group to cycle the action by utilizing high pressure gas from behind a bullet during firing. In a centerfire configuration, high pressure gas may unlock a bolt and push the bolt rearward to cycle action. In a rimfire conversion configuration, a gas tube may be connected to a rifle bore and high-pressure gas may be bled off but may not be used to cycle the firearm.
Further embodiments of the present disclosure may provide a firearm reliability system comprising: a variable bolt weight assembly (VBWA) that may slip under a spring guide rod extension of a bolt assembly and contact a back of a bolt, wherein a weight body of the VBWA is behind a bolt as it closes to eliminate bolt bounce with two impacts. The two impacts are the weight body to the rearward moving bolt and internal weights of the VBWA to the rearward moving bolt and a bolt body. The back of the bolt may include a notch that engages a notch present on the spring guide rod extension of the bolt assembly. The VBWA may contact the back of the bolt near a firing pin and/or the VBWA may contact the back of the bolt on a keyed area on a back of the spring guide rod extension.
Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions and claims.
For a more complete understanding of this disclosure, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
Embodiments of the present disclosure may provide a firearm reliability system that may include a charging handle insert and a variable bolt weight assembly. Other components of a firearm reliability system may include, but are not limited to, a buffer pressure plug, extractor springs, firing pin springs, one or more firing pins, bolt buffers, and collars as described in more detail herein. The firearm reliability system according to embodiments of the present disclosure may address one or more weaknesses in the common Ciener/Atchisson style rimfire bolt system (RBS) for the ArmaLite Rifle (AR) that is known to be prone to frequent malfunctions. With the firearm reliability system according to embodiments of the present disclosure installed, malfunctions may be essentially eliminated from the system. Each component of the firearm reliability system according to embodiments of the present disclosure plays a part and interfaces with the others (i.e., the bolt weight may spread the impact on the buffer into a larger area, while reducing the speed at which the bolt impacts the backplate, which then may reduce the energy transferred to the buffer pressure plug and thus, the impact with the lower receiver).
A charging handle insert (hereafter CHI) according to embodiments of the present disclosure may increase cycling reliability by preventing rimfire casings from getting caught in the charging handle and to deflect gas away from the shooter during firing. The CHI according to embodiments of the present disclosure may allow the shooter to train using his/her normal charging handle while still getting the reliability and gas deflection benefits of a rimfire-specific charging handle. The CHI may press into the gas key channel of a centerfire charging handle (hereafter CCH) of an ArmaLite Rifle pattern firearm. The CHI may be retained in the channel of the CCH by friction between the sides of the CHI and CCH channel.
The CHI can be used with either a dedicated rimfire firearm or centerfire firearm with a chamber adapter style rimfire conversion kit installed. In a dedicated rimfire firearm, the CHI may fill the gas key channel in the CCH to prevent malfunctions from empty rimfire casings that may become lodged in the CCH gas key channel. In a centerfire firearm with a rimfire conversion, the CHI may fill the gas key channel in the CCH to prevent malfunctions from empty rimfire casings that may become lodged in the CCH gas key channel. In this application, the CHI also may reduce gas blowback towards the shooter. The gas has two primary sources: 1) gas leakage through the gap between the centerfire chamber and the rimfire chamber adapter and 2) gas from the open gas tube which points rearward within the CCH gas key channel. Without the gas key of the centerfire bolt carrier group, gas escaping from the gas tube during firing travels without obstruction down the CCH gas key channel towards the operator. The CHI may block the flow of gas and a gas deflection feature may redirect the gas downward. This may reduce or eliminate gas blowback through the gas key channel. The CHI may be symmetrical to avoid orientation mistakes when inserting into the CCH and may be manufactured from polymer or metal by additive, subtractive, or molding manufacturing processes.
CHI 10 features gas deflection cutouts to redirect gas from the open gas tube and block the open channel leading back towards the shooter, reducing the puff of gas felt when shooting a rimfire conversion kit in a centerfire rifle. CHI 10 may include a semi-cylindrical lower profile to match the semi-cylindrical profile of a gas key channel of CCH 20 (
Embodiments of the present disclosure may provide a variable bolt weight assembly (hereafter VBWA) that may add user variable mass to an AR rimfire bolt assembly found in most rimfire AR rifles. The VBWA may slip under the spring guide rod extension of the bolt assembly (
Rimfire ammunition spans a large spectrum in terms of the energy generated by the cartridge. In commonly available 22LR cartridges, bullet weights vary from 30 to 60 grains with velocities ranging from 700 to 1700 feet per second. As such, the bolt thrust and thus bolt velocity in a pure blowback operated semi-automatic rifle can vary significantly. To create reliable and safe operation, the bolt mass must be matched to the energy generated by a specific load. In a rimfire AR pattern firearm, the bolt mass is fixed and unable to be tuned by the user for each load. Often, the mass is far too low, and excessive bolt velocity may be observed. The VBWA may be inserted behind the bolt in an AR pattern rimfire action and add mass to the system to allow the user to tune the rifle to the specific load for perfect cycling and control of excessive bolt velocity. The user can remove the back plate from the VBWA by removal of screw(s) to access the weight inserts. Inserts of different materials ranging from very light polymers to tungsten can be installed in various combinations to precisely add or remove weight from the system, thus tuning the bolt for any load across a large number of available rimfire loadings and rimfire cartridges.
The VBWA according to embodiments of the present disclosure may provide an assembly with the parts provided to allow the user to vary the weight by small increments by adding or removing weights of different materials and densities. A simplified monolithic VBWA may add a fixed weight to the system that is intended to fit the largest number of loadings possible without the added part count and thus cost and complexity of the VBWA. The simplified weight and the individual parts comprising the VBWA according to embodiments of the present disclosure may be manufactured from metal or polymer by additive, subtractive, or molding manufacturing processes.
In embodiments of the present disclosure, the VBWA may include internal weights made from aluminum, steel, and tungsten which may be used to adjust the weight from approximately 1 oz to 3 oz, depending on the internal weight types used. Mixing and matching material types may give additional variability. The weight system may be tuned by starting with the weight in a low-weight configuration and adding weight until performance of the system is optimized and last round bolt hold open is reliable. If last round bolt hold open is not achieved, the bolt weight should be reduced. It should be appreciated that each hole should always be either completely empty or contain two weights; only one weight should not be installed.
The main purpose of a bolt weight is to eliminate bolt bounce in the system. The two types of weights both do this, but the adjustable weight may be preferred in embodiments of the present disclosure as the sliding internal weights may provide a second degree of damping to the bounce. When the bolt closes chambering a round and impacts the bolt collar, it bounces off With an adjustable weight, the weight body is a small distance behind the bolt as it closes, which eliminates some of the bolt bounce by impacting the rearward traveling bolt (after it bounces off the collar) and slowing the rearward motion. Any rearward motion that is still happening is stopped when the internal weights then slide forward, impacting the front of the holes inside the weight, stopping more rearward motion. With a “standard” weight, there is one impact (weight to bouncing, rearward moving bolt). With an “adjustable” weight, there are two impacts: the weight body to bouncing, rearward moving bolt followed by the internal weights to the rearward moving bolt and bolt body. The different materials allow for the user to tune the weight of the bolt weight to a weight which still allows the rifle action to cycle (too much weight will stop cycling), as well as tune the amount of secondary impact from the internal weights to reduce bolt bounce to an acceptable level.
Secondarily, it adds weight to a bolt that is very much underweight (as compared to other blowback rimfire platforms) which drops bolt velocity, reducing overall wear on the rifle. This also holds the bolt closed slightly longer, allowing for more of the powder to burn while the casing is in the chamber and allowing pressure in the chamber and bore to drop before the casing is extracted. This reduces fouling inside the rifle's action (from the reduction in gas and unburned powder that are otherwise released when the case is extracted prematurely) and reduces sound (known colloquially as “port pop”) from expanding gasses released from the breech when casing extraction is premature. Reducing port pop makes the rifle quieter to the shooter, especially when a suppressor is in use. When used in a full auto rifle, the elimination of bolt bounce makes full auto fire reliable. The bolt bouncing would often result in stoppages since the hammer would hit the rebounding bolt rather than the firing pin, which at best would cause the rifle to stop firing and have a dead trigger (hammer down on a loaded chamber) or at worst for the hammer to set the cartridge off out of battery, resulting in a casing rupture and potential damage to the rifle or injury to the shooter.
A bolt weight assembly may slip under the tubular recoil spring housing, and the notch on the back of the bolt may engage a notch present on the tubular recoil spring housing. There may be some play in the bolt weight fit due to variations in the bolt assembly, but this will not harm the performance of the bolt weight. It should be appreciated that some users find it easier to depress the firing pin by hand and slide the weight directly in, while others may find it easier to put the front of the weight in place and then rotate the back of the weight under the tubular recoil spring housing until the notch is engaged.
Extractor springs may be provided in two different strengths for better extraction especially as the chamber becomes fouled. To install, the extractor pin out may be driven from top to bottom, and the extractor and spring may be removed. The spring may be replaced with an increased power extractor spring, the hole may be aligned in the bolt and extractor, and the pin may be reinserted. The heavier extractor springs may increase extraction reliability and also may help with a more consistent ejection pattern, which may further reduce the possibility of malfunctions.
Buffer pressure plug 50 may include retention slot 501 in which the buffer pin may rest to keep plug 50 aligned. Retention slot 501 may also allow use of a coin, flat blade screwdriver, or other similar object to be used to twist plug 50 for insertion or removal. Insertion slot 502 disposed along the length of the cylinder of plug 50 may allow quick and easy insertion without a need to depress the buffer retaining pin. Insertion slot 502 may be aligned with the buffer retention pin and then may be pushed straight rearward to insert.
Plug 50 may be inserted by pulling the rear takedown pin and hinge the upper receiver away from the lower receiver. Insertion slot 502 may be aligned with the buffer retainer pin, pressed straight back, and plug 50 may be twisted ¼ turn in either direction to allow the buffer pin to drop into retention slot 501. Plug 50 can be inserted either direction, but in embodiment of the present disclosure, the hollow side may be inserted towards the buffer. The upper receiver may be closed, and the rear takedown pin may be replaced. Removal is the reverse of installation. On some buffer springs, the spring may become preloaded from twisting plug 50 ¼ turn. While this does not cause damage or affect the function of plug 50, some users find it useful to turn plug 50 ½ turn and then back ¼ turn to remove the rotational preload of the buffer spring. While most rifles will allow plug 50 to be rotated with ease, if difficulty is encountered, use a coin in the retention slot to help with turning plug 50.
A firing pin spring may be installed on a narrow end of a firing pin (
A firing pin according to an embodiment of the present disclosure (
A modified collar may be provided that can take a set screw to lock a chamber adapter into the collar, which may allow for a dedicated rimfire group to be used in a centerfire gun through a chamber adapter that can be inserted and locked in and removed for use in a dedicated rimfire rifle. It should be appreciated that some users may use the same bolt group with both a dedicated rifle and in a centerfire gun through the use of a chamber adapter. Rifling may be included in the adapter to increase accuracy and/or the bolt group may include both smoothbore and rifled versions in embodiments of the present disclosure. Utilizing a collar, the addition of a threaded hole (rather than a pressed-in ball spring plunger that is currently in use in some other collars) may allow for (1) the use of a chamber adapter that interfaces with and can be locked into a standard dedicated rimfire collar (rather than a monolithic piece combining chamber adapter and collar as currently embodied in other designs); and (2) the user to choose to use either the standard ball spring plunger retention on a dedicated rimfire barrel or the set screw to lock the collar to the barrel for a positive lock of bolt to barrel for those users who desire increased rigidity and positive location on the rimfire bolt group which may increase overall accuracy and reliability of the rifle with installed rimfire bolt.
Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/916,435 filed on Oct. 17, 2019, entitled “Charging Handle Insert” and U.S. Provisional Patent Application Ser. No. 63/012,647 filed on Apr. 20, 2020, entitled “Variable Bolt Weight Assembly,” both of which are incorporated by reference in their entirety.
Number | Date | Country | |
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62916435 | Oct 2019 | US | |
63012647 | Apr 2020 | US |