Adjustable carrier

Disclosed herein is a modified rifle bolt carrier allowing a selectively openable vent/valve at the location where exhaust gas is pressurizing the bolt carrier to control carrier speed under suppressed fire in a first valve position or unsuppressed fire in a second valve position. A valve core is disclosed which may be rotated 180° to a first “open” setting for non-suppressed fire from its position in a “closed” position for suppressed fire, and a third “median” position. The modified bolt carrier will allow an operator of the firearm to adjust for a suppressor without changing the gas block or having to modify or adapt the front end or barrel end of the firearm.

BACKGROUND OF THE DISCLOSURE

FIELD OF THE DISCLOSURE

This disclosure relates to the field of firearms modified for suppressed and un-suppressed fire, for varying powder loads, for varying projectile configurations, etc.

BRIEF SUMMARY OF THE DISCLOSURE

Disclosed herein is a firing assembly for a firearm. The assembly in one example comprising: a bolt carrier having a longitudinal axis, a surface defining a gas port. One example of the gas port in fluid communication with a gas block forward of a chamber of the firearm via a gas tube when the firearm is assembled. Also disclosed is a surface of the bolt carrier defining a valve housing in fluid communication with the gas port. Inserted into the valve housing is a valve core having an outer surface. The valve core configured to rotate within the valve housing without appreciable gas transfer between the outer surface of the valve core and the valve housing. One example of the valve core having a lateral end larger in diameter than the valve housing; a sealing member radially compressed between the valve core and the valve housing; and the valve core having a surface defining a port at least partially and selectively controls flow thorough the gas port.

The assembly may be arranged wherein the outer surface of the valve core is in close sliding fit to the valve housing so as to rotate therein.

The assembly may be arranged wherein the valve core comprises an indexing component; wherein the indexing component of the bolt carrier is in contact with an indexing surface of the bolt carrier, providing additional rotational friction to rotation of the valve core within the valve housing.

The assembly may be arranged wherein: the sealing member is configured to bias the valve core laterally; and wherein the sealing member is configured to laterally bias the indexing component toward the indexing surface.

The assembly may be arranged wherein: the valve core comprises a valve port surface which is detented from the substantially cylindrical outer surface of the valve core; and wherein the valve port surface is selectively aligned with the vertical gas port of the bolt carrier in an unsuppressed position such that the valve core does not substantially occlude the vertical gas port.

The assembly may further comprise a valve depressed surface on the valve body radially opposed to the valve port surface relative to the substantially cylindrical outer surface of the valve core.

The assembly may be arranged wherein; the valve core comprises an indexing component; and wherein the indexing component of the bolt carrier contacts an indexing surface of the bolt carrier, providing additional rotational friction to rotation of the valve core within the valve housing when the valve port surface is selectively aligned with the vertical gas port of the bolt carrier in an unsuppressed position.

The assembly may further comprise: a tool engagement surface on the valve core; the tool engagement surface not circularly symmetric; and a tool having a surface to cooperate with the tool engagement surface so as to selectively provide rotational force to the valve core when the tool is rotated.

The assembly may be arranged wherein the sealing member is radially compressed between the valve core and the valve housing.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1is an isometric view of one example of the adjustable bolt carrier with gas regulator installed therein.

FIG. 2is a first side view of the example shown inFIG. 1.

FIG. 3is a first end view of the example shown inFIG. 1.

FIG. 4is a second end view of the example shown inFIG. 1.

FIG. 5is a second side view of the example shown inFIG. 1from the opposing side as that shown inFIG. 2.

FIG. 6is a top view of the example shown inFIG. 1.

FIG. 7is a bottom view of the example shown inFIG. 1.

FIG. 8is an isometric view of one example of valve core and sealing member components ofFIG. 1.

FIG. 9is an end view of the example shown inFIG. 8.

FIG. 10is an opposing end view of the example shown inFIG. 9.

FIG. 11is a top view of the example shown inFIG. 8.

FIG. 12is a bottom view of the example shown inFIG. 8.

FIG. 13is a side view of the example shown inFIG. 8.

FIG. 14is an opposing side view of the example shown inFIG. 13.

FIG. 15is the same view as shown inFIG. 14with a sealing member removed.

FIG. 16is a partial hidden line view of the adjustable carrier component ofFIG. 1.

FIG. 18shows a prior art firearm and several components thereof shown in a combination exploded view.

DETAILED DESCRIPTION OF THE DISCLOSURE

Disclosed herein is a modification to a rifle bolt carrier providing a selectively openable and adjustable gas valve. In one example this gas valve is at the location where exhaust gas engages the bolt carrier. In one example, the valve is used to control carrier speed while shooting.

A valve body is disclosed configured to be rotated to adjust the volume of gas (air) that passes therethrough. The modification will allow an operator (shooter) of the firearm to adjust the carrier movement without changing the gas block and without having to modify or adapt the front (muzzle) end of the firearm.

A description of operation of an AR 15 style firearm and apparatus is included herein to give background to the invention. It is to be understood that this is one example and the apparatus may be applied to SR25, AR10, and other firearm platforms. On example of this is shown inFIG. 18; representing known parts of such a firearm20. Although an AR15 firearm is used as a specific example for description in this disclosure, it is to be understood that the modification disclosed herein may be applied to other firearms having equivalent components and/or operation. This example shows a cartridge24configured to fit in the chamber22. This example further showing a hammer26in a rearward position. When fired, the user (shooter) actuates a trigger28which releases the hammer26towards a firing pin30. The hammer contacts the firing pin30, driving the firing pin30forward towards the primer portion32of the cartridge24.

An understanding of “headspace” in this context aids in understanding the description herein. In describing firearms and firearm operation, headspace is the distance measured from the part of the chamber22that stops forward motion of the cartridge24(the datum reference) to the face33of the bolt58.The term “headspace” used herein refers to the interference created between the inner surface of the chamber22and the feature(s) (shape) of the cartridge24that achieves the correct positioning of the cartridge24in the chamber22. Different cartridges24have their datum lines in different positions in relation to the end surfaces of the casing38. For example, 5.56 NATO ammunition headspaces off the shoulder34of the cartridge24, whereas .303 British headspaces off the rim36of the cartridge24. If the headspace is too short, even cartridges that are in specification may not chamber correctly. If headspace is too large, the casing38of the cartridge may rupture when fired, possibly damaging the firearm and injuring the shooter.

Before continuing with a description of the disclosed apparatus, an axes system10is shown in the drawings. The axes system10including a longitudinally rearward direction and a longitudinally forward direction, each along the longitudinal axis12. The axes system including a lateral axis14orthogonal the longitudinal axis12and parallel to the axis of rotation18of the valve core to be described in detail. The axes system also including a transverse axis16orthogonal to the longitudinal axis12and the lateral axis14.

Returning to a description of the firing system; as the firing pin30continues moving longitudinally12forward12ato impact and ignite the primer32, the primer detonation ignites the powder charge40within the cartridge24, creating pressure within the cartridge casing38. As the cartridge24expands radially outward towards the radially inward chamber walls; the chamber holds the casing38in place. As the caning38stretches longitudinally rearward, the case head76is stopped against the bolt face33.

It is common for the casing38which is commonly made of brass to stretch rearward up to 2-4 thousandths of an inch when fired. The casing will return to its original shape and size when chamber pressure subsides. This also allows for reloading for center fire primers.

It is generally undesirable to provide headspace for the cartridge24to yield (permanently stretch) as the casing38is often thin just above the extraction groove. Excessive headspace is evident on a casing as a shiny ring, often about ⅛″ forward of the extraction groove.

Upon detonation of the powder charge40, the bullet42(projectile portion of the cartridge) begins movement down the barrel44of the firearm20, first encountering the throat of the barrel44. It is often important for the throat diameter to closely match the bullet diameter. Generally, oversized throats do not control the bullet42and do not keep the bullet42as straight while engraving into the rifling of the barrel44.

As the bullet42travels down the barrel, the bullet42may expand radially outward into the rifling, where pressure causes the rifling lands to “engrave” into the bullet. Depending on the aspect ratio of the lands to grooves, the bullet42will sometimes increase in length. This change in bullet42shape can often be detrimental to accuracy. As the bullet42has obturated and engraved into the rifling the bullet42accelerates down the bore52of the barrel44.

As the bullet approaches a gas port / gas block46of the firearm, expanded gas begins to flow into the gas block46where it flows towards the bolt carrier50via the gas tube54and bolt carrier key48. The bolt carrier key48may be attached to or formed with the top of the bolt carrier50.

While shooting the firearm20, the gas pressure is relatively high in the barrel44, often 15,00PSI + until the bullet42leaves the muzzle end56of the barrel. As the bullet42leaves the muzzle end56, gas escapes the barrel44around the base of the bullet42.

High pressure gas will flow along the path of least resistance, at this point out the muzzle end56of the barrel44instead of into the gas system driving the bolt carrier50and associated components rearward12. As the bullet42exits the barrel44; pressure within the barrel44and chamber22drops. During the bullets travel down the barrel44some pressurized gas travels from the gas block50through the gas tube54to the bolt carrier key48.

The gas (pressure) upon reaching the bolt carrier key48is conducted to the bolt carrier50where the pressurized gas expands. Gas expanding in this region of the bolt carrier50forces the bolt carrier50rearward12band simultaneously forces the bolt58longitudinally forward12a. The bolt58is also forced rearward by the gas pressure expanding the cartridge casing38. For a short moment in time, these forward12aand rearward12bforces are substantially equal. During this moment, the bolt lugs60unlock prior to the extractor62forcing the spent casing38rearward and laterally outward through ejector port86. At this point the bolt carrier50begins to move rearwards12against the inertia of the bolt carrier's weight, the weight of a buffer64, and the tension of an operating spring70. All of these relative movements affect timing of the mechanical operation as the firearm20is fired. Buffers64are provided in several “weights” to account for these and other factors: standard, heavy (H), H2, H3 etc.

As the bolt carrier50travels rearward, a cam pin66provided through the bolt encounters cam surfaces. Rearward movement of the bolt carrier50as the cam pin66contacts the cam surfaces causes the bolt58to rotate relative to the chamber22.

As the firearm20is fired, gas pressure in the casing38holds the casing38into the chamber22, even though the chamber22may be slightly tapered.

As the gas pressure is released out the muzzle end56of the barrel44, the cartridge casing38will substantially return to its previous size. Thus the casing38is no longer a tight fit in the chamber22as during firing when the gas pressure within the casing38is high.

It is important to operation that the bullet42exits the muzzle end56of the barrel44and the gas pressure within the casing38reduces enough that the casing38returns substantially to its pre-fired size, before the bolt lugs60are unlocked. Often, when the pressure is high during this operation, the casing38can become jammed in the chamber22. One indicator of such high pressures is that the casing38extrudes into the ejector plunger hole on the bolt58and the resulting pressure unlocks the bolt58while gas pressures are still high.

Returning to a description of extraction of the spent cartridge24or casing38, as pressure subsides, the bolt58is unlocked, bolt carrier48momentum continues rearward12, pulling the spent cartridge casing38from the chamber22.

As the casing38reaches the ejection port86, the spent casing38pivots on the extractor hook from pressure of the ejector until the spent casing38is ejected from the firearm20through the ejector port68.

The bolt carrier48continues rearward after ejection of the spent cartridge24while re-setting the hammer26of the firearm20to a position ready for firing until operating spring70pressure on the buffer64stops rearward12motion of the bolt carrier48.

Once rearward12motion of the bolt carrier48ceases, the operating spring70(buffer spring) returns the bolt carrier48forward. As the bolt carrier48travels forward the mechanism strips a new unfired cartridge24from the magazine72up a feed ramp and into the chamber22. The cartridge24stops forward12amotion as the cartridge24is seated in the chamber22, the bolt58continues forward, causing the extractor62to snap over the rim74of the cartridge casing38. The bolt58will stop against the case head76, and the bolt carrier50continues longitudinally forward12a. The cam surfaces of the bolt carrier48then cause the bolt58to lock into firing position. The firearm20is then set as described at the beginning of this process.

When shooting, many shooters prefer to use sound or flash suppressors78on firearms20to reduce muzzle audio volume or muzzle flash. One problem with such suppressors78is the effect such suppressors78have on firearm function, particularly to bolt carrier48movement during firing. Gas pressure increases within the gas tube54and bolt carrier key48is a common result of suppressor attachment to firearms.

A semi-automatic firearm for example requires a specific volume/pressure of gas directed to the bolt carrier48to function properly as described above. When fired without a suppressor for example, the majority of excess gas pressure expands out of the muzzle end56of the barrel44into the atmosphere after the bullet42exits the bore52. When that same gas pressure is affected by a suppressor's baffles, instead of exiting freely from the muzzle56, a significant volume of pressurized gas is held in the gas system/barrel44. Some of this compressed gas is directed to the gas block50, through the gas tube54, to the bolt carrier50. The resulting greater force applied by this increased pressure/volume of gas to the bolt carrier50is often more than needed to operate the action of the bolt carrier50and bolt58, and therefore can result in malfunction or damage of the firearm. The same effect can be caused by variances in powder charge40, bullet42size, weight, shape, tension of the operating spring70, and other variables. A modification is thus disclosed herein of a valve82to offset such variance in gas pressure.

Direct-gas-impingement systems as disclosed above, are typically non-adjustable as built. While user-adjustable regulators are available as commercial retrofits, they fail to fit the needs of shooters wishing to change from suppressed to non-suppressed fire in the field. These adjustable regulators often rely on setscrews for adjustment, or locking, and often lack positively indexed positions. Other known options to adjust changes to bolt and carrier speeds include installing heavier bolt carriers, changing buffer/operating springs70and changing buffers64. Internal suppressor-design differences yield vastly different performance results depending in part on the firearm20to which they are attached and the cartridge24used.

As described, suppressors78and other variables normally affect pressure inside a firearm's gas system, in particular gas pressure provided to movement of the bolt carrier48. Two known common ways to account for this change in gas pressure to the bolt carrier is to increase buffer64weight or use a hydraulic buffer.

Disclosed herein as shown in the example ofFIG. 1is a modified rifle bolt carrier80providing a selectively openable valve82at a location where exhaust gas is directed from the bolt carrier key48(FIG. 18) to the bolt carrier80to control carrier speed under suppressed fire in a first valve position (S), unsuppressed fire (U) in a second valve position, and/or medial fire (M) in a third position. In other examples, the valve83may be configured without indexing, or may be indexed to other variables including powder charge40, bullet42weight, barrel44length, suppressor78, etc.

To adjust operation of the gas operated bolt carrier80, the valve82comprising a valve core84may be fitted within a surface defining a valve housing88(FIG. 16) as disclosed. In one example, the disclosed system includes a valve core84which may rotate between aa first or “open” (U) position for un-suppressed fire, a second (S) position for suppressed fire, and a “median” (M) position.

In one example, an indexing surface106on the modified bolt carrier engages a surface of the valve82to index the valve core84at various positions. These indexing surfaces may me substantially indents into which an indexer engages as the valve core84rotates in the valve housing88. The modified bolt carrier80with the valve82will allow an operator of the firearm20to adjust for a suppressor78or other variables such as powder charge, bullet size or configuration, weather, barometric pressure, etc. without changing the gas block46or changing the front (muzzle) end56of the firearm20.

FIG. 16shows a partial hidden line view of a section of the modified bolt carrier80shown orthogonal to a gas port90. As shown, when the firearm20is assembled, the gas port90with all other components provides a fluid (gas) conduit from the barrel44(gas port46) to the gas tube54via the bolt carrier key48. The bolt carrier key48may be attached to the bolt carrier80by way of fasteners92which engage female threaded voids94in the modified bolt carrier80. In another example, the bolt carrier key48may be formed with the bolt carrier80. As shown, the gas port90provides a gas conduit from the bolt carrier key48to an inner chamber96of the modified bolt carrier80as previously described. The valve82as described comprises several components including the valve core84fitted into the valve housing88which in this example comprises a female surface98into which the outer surface100of the valve core84fits in a close sliding fit; one example shown inFIGS. 8-15. The surfaces98/100may be cylindrical, conic section, arcuate projections, or other shapes or combinations thereof. Substantially cylindrical surfaces are shown in the drawings for ease in illustration.

A close sliding fit is defined herein as an engineering fit between two parts without a noticeable gap there between. In such an assemblage there is no noticeable gap between the cylindrical outer surface100of the valve core84and the surface98of the valve housing88which may otherwise allow gas pressure to transfer there between.

To ensure a gas-tight (close sliding) fit, as well as to induce friction without stiction (the friction that tends to prevent stationary surfaces from being set in motion) a sealing member114may be provided. In one example, the sealing member114is pressed in a circumferential groove116in the valve core84to ensure proper placement and operation. The sealing member114may be a cylinder, toroid, cone, frusta of these surfaces, or other shapes. In one example as shown inFIG. 8-14the sealing member114is a toroid-shaped O-ring prior to compression. A shape well known in the art. The sealing member114may be made of silicone, rubber, metal, plastic, Polyethylene, or equivalent materials. In one example the sealing member is substantially elastic, substantially returning to its original shape and size when not compressed/tensioned. In one example the sealing member114has a Durometer rating of between30and70on the Shore “A” scale. This allows for substantial compression during installation. The circumferential groove116may be conic, a toroid section, or may be cylindrical as shown, with a circumferential surface118and side surfaces120aand120b.

When installed in the valve housing88, a first lateral end122of the valve core84fits within a recess138in the modified carrier80such that the first lateral end122does not project radially outward past the adjacent outer surface140of the modified bolt carrier80. In this way, the first lateral end122of the valve core84does not contact the inner surface of the receiver126which would tend to be detrimental if not terminal to operation.

In one example, the second lateral end128of the valve core84comprises a surface defining a void130. During assembly, the valve core84is inserted into a first lateral side134of the valve housing88, and the sealing member114seals between the valve core84and the valve housing88to a fully inserted position. In one example, the sealing member114is compressed between the surface120aof the valve core84and an inner lateral facing surface136of the valve housing. As so compressed, the sealing member114biases the valve core84laterally away from the surface136. To offset this bias, a pin132or other component is utilized. The pin132may be pressed (e.g. press fit), threaded, welded, or otherwise secured to the valve core84.

In one example, the indexing component108previously described and the pin132are the same structure, accomplishing both functions. In other examples the indexing component108and the pin132are separate structures.

As can be seen in the cutaway view ofFIG. 17, the sealing member114may be significantly compressed radially and laterally to form a seal, to provide constant friction between the valve core84and the valve housing88without stiction, and to laterally bias the valve core84away from the surface136. This compression also pressing the pin132toward (into) the indexing surfaces106. This bias increasing the effectiveness of the indexing system.

As can be appreciated by looking toFIG. 6, when the valve port surface102of the valve core84is aligned with the gas port90, the valve core84provides little or no obstruction to gas transiting the gas port90. In one example, this unsuppressed (U) position, allows use of the firearm without a suppressor. When the valve core84is rotated, the valve port surface102may not be aligned with the valve port90. In such a position for example indexed positions “M” or “S”, the valve core84occludes at least a portion of the gas port90. In one example, this is a suppressed (S) position where use of the firearm with a suppressor is facilitated in that the valve core84reduces the gas volume and pressure transferring between the48and the bolt carrier50.

Looking to the example ofFIGS. 11 and 13-14it can be seen that the valve core84also comprises a valve depressed surface104. While shown as a substantially planar surface, the valve depressed surface104may be specifically configured to conform to a specific combination of firearm/ammunition/suppressor to provide the proper gas flow there past through the gas port90. When in the suppressed (S) setting the valve core84restrict the gas passing thereby. In this suppressed (S) setting, gas pressure is vented past the valve depressed surface104. This structure resulting in a longer time for the pressure to build, in turn causing the action stay in lockup longer, and in turn direct more of the barrel pressure through the bore52.

In the example shown a plurality of indexing surfaces106(106b,106s,106u,106m) are provided on the bolt carrier80. In one example these indexing surfaces106are grooves in the bolt carrier80, extending radially from the rotational axis of the valve core84. A corresponding indexing component108of the valve core84is configured to engage the surface106of valve core84relative to the bolt carrier80. In addition, indicators110(110s,110m,110u) may be provided for indication of the position of the valve core84in an unsuppressed fire position (110u), suppressed fire position (110s) and median position (110m) respectively. Other indexing surfaces may be used for other variables.

In one example, to rotate the valve core, a shooter may use a tool to engage a tool surface124.

In one example, the outer portion of the valve core84may comprise the tool engagement surface124for engagement with a tool126which in the example shown may be a flathead screwdriver not shown as such tools are commonly known. Other screwdriver designs, Allen wrenches, and drive patterns known in the art or designed for this specific purpose may be used. The tool allows the shooter to overcome rotational friction between the valve core84and the valve housing88, including friction induced by the sealing member114. The engagement portion of the tool is configured to interoperate with the engagement surface124and rotate the valve core84when the tool is rotated.

In one form, the tool and the mating surface124may comprise a surface which does not have circular symmetry. This surface may be used to engage the tool surface124as described above.

While the present invention is illustrated by description of several embodiments and while the illustrative embodiments are described in detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the scope of the appended claims will readily appear to those sufficed in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants' general concept.