Patent Application
20200318928
The present invention generally relates to firearms, and more particularly to a free-floating barrel mounting system for firearms such as rifles or carbines.
To improve the shooting accuracy of long guns such as rifles or carbines especially for competition shooting, it is often desirable to provide a free-floating barrel. Such barrels are coupled to the receiver and typically receive no significant support from the stock, chassis, or handguard. Because there is no physical coupling between the barrel and stock or handguard in true free-floating barrel designs, the barrel is not restrained allowing it to grow and expand freely when heated by repeated firing of the rifle to avoid thermal distortion.
Improvements in barrel mounting systems are desired.
Embodiments of the present invention provide an improved barrel mounting system for coupling the barrel to the receiver in a manner which provides a free-floating barrel mount. The firearm may be a long gun such as a rifle or carbine as some non-limiting examples.
The free-floating barrel mounting system generally includes upper and lower barrel mounting features above and below the barrel bore centerline respectively which detachably couple the barrel to the receiver. The mounting features are configured and operable to compress a flat rear face of the barrel against a mating flat front face of the receiver for retaining the barrel. The lower mounting feature may comprise an assembly of a clamping block and pair of securement fasteners threadably engaged with the receiver which compress a lower breech end portion of the barrel against the receiver. The upper mounting feature may comprise a single securement fastener engaged with the receiver which compresses an upper breech end portion of the barrel against the receiver. In one embodiment, the upper securement fastener is centered over the breech end of the barrel. The upper and lower securement fasteners form a triangular bolting pattern and advantageously balance moment forces created by the compressive forces of coupling the barrel to receiver with the fasteners.
In one aspect, a free-floating barrel mounting system for a firearm includes: a longitudinal axis; a receiver; a barrel detachably coupled to the receiver, the barrel comprising a front muzzle end, a rear breech end, and an internal bore defining a bore centerline and extending axially between the ends to define a projectile passageway; a lower mounting feature below the bore centerline comprising a clamping block arranged in proximity to the breech end of the barrel, the clamping block configured to compress a lower portion of the breech end against a front face of the receiver; an upper mounting feature above the bore centerline comprising an upper securement fastener configured to threadably engage the receiver and compress an upper portion of the breech end of the barrel against the front face of the receiver; wherein moment forces created by the lower mounting feature are balanced by the upper mounting feature.
In another aspect, a free-floating barrel mounting system for a firearm includes: a longitudinal axis; a receiver defining a front face and a forward extension projecting axially from the front face; a barrel comprising a front muzzle end, a rear breech end, and an internal bore defining a bore centerline and extending axially between the ends to define a projectile passageway; the breech end of the barrel being cylindrical and received in an unthreaded barrel mounting hole in the front face of the receiver; an external shoulder formed between the breech end and a portion of the barrel forward of the breech end, the shoulder defining an annular rear face abuttingly engaged with the front face of the receiver; a clamping block arranged below the bore centerline and engaged with the forward extension of the receiver; a pair of spaced apart lower securement fasteners extending axially through the clamping block and threadably engaging the forward extension of the receiver; an upper securement fastener arranged above the bore centerline and threadably engaging an axial bore in the front face of the receiver; a portion of the upper securement fastener abuttingly engaging a forward facing upper bearing surface formed on a top of the barrel; wherein tightening the upper securement fastener compresses the annular rear face of the barrel against the front face of the receiver; wherein moment forces created by tightening the lower securement fasteners are balanced by the upper securement fastener.
In another aspect, a method for coupling a barrel to a receiver of a firearm includes: axially aligning the barrel with the receiver; slidably inserting a rear breech end of the barrel into a corresponding barrel mounting hole in a front end of the receiver; abuttingly engaging a rear face of the barrel with a front face of the receiver; engaging a lower forward portion of the receiver with a clamping block below a bore centerline of the barrel; inserting at least one lower securement fastener through the clamping block; threadably engaging a pair of lower securement fasteners with the receiver; tightening the lower securement fasteners to draw and clamp a bottom portion of the barrel against the front face of the receiver; threadably engaging an upper securement fastener with the receiver above the bore centerline of the barrel to trap a portion of the barrel between an enlarged head of the upper securement fastener and the receiver; and tightening the upper securement fastener to draw a top portion of the barrel against the front face of the receiver; wherein moment forces created by tightening the lower securement fasteners is balanced by the upper securement fastener.
The features of the exemplary embodiments will be described with reference to the following drawings where like elements are labeled similarly, and in which:
All drawings are schematic and not necessarily to scale. Parts shown and/or given a reference numerical designation in one figure may be considered to be the same parts where they appear in other figures without a numerical designation for brevity unless specifically labeled with a different part number and described herein.
The features and benefits of the invention are illustrated and described herein by reference to preferred but non-limiting exemplary (“example”) embodiments. This description of the embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. Accordingly, the invention expressly should not be limited to such embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto.
In the description of embodiments disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures may be secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.
Firearm 20 includes a longitudinal axis LA, receiver 21, barrel 22 coupled thereto, bolt 50, and a trigger-actuated firing mechanism 23 which may be supported by the receiver or a detachable trigger housing 23-1 as illustrated. Firing mechanism 23 includes a movable trigger 24 for actuating the mechanism. The firearm includes a chassis or stock 80 including buttstock 81, mid-stock 82 to which the receiver 21 is mounted by a pair of takedown screws 21-1, and a forearm 83 extending for a portion of the length of the barrel 22. As best seen in
A downwardly open magazine well 32 is formed by the receiver 21 which holds an ammunition magazine 33 comprising a plurality of cartridges detachably mounted in the well. Such magazines may a straight or curved box-style which contains a spring-biased stack of ammunition cartridges which are uploaded into the breech area 34 by a spring mechanism for chambering into the rearwardly open chamber 36 of barrel 22 by the bolt 50 in a conventional manner when cycling the action (example of box magazine illustrated schematically by dashed lines in
The magazine 33 is removably retained in the magazine well 32 by a pivotable magazine release such as elongated lever latch 35. Latch 35 may be pivotably mounted by transverse pivot pin 105 to the receiver 21, or alternatively as shown in the figures by detachable trigger housing 23-1 which houses the firing mechanism. Latch 35 is mounted proximate to the rear of the magazine well 32 and has a front end configured to engage and retain magazine 33 in the firearm. Latch 35 may have an elongated body which has a compound curved shape complementary configured to the shape of the trigger guard 24-1 as best shown in
Barrel 22 has an elongated tubular body including an axial bore 37 extending longitudinally and axially from a rear breech end 38 to a front muzzle end 39 from which a bullet or slug is discharged from the firearm. The centerline of bore 37 is coaxial with and defines the longitudinal axis LA of the firearm. A vertical reference plane VR intersects and extends along the longitudinal axis LA for convenience of description. The rear breech end 38 of the barrel 22 defines a rearwardly open diametrically enlarged chamber 36 configured for holding an ammunition cartridge. Chamber 36 communicates with bore 37 which forms the projectile passageway for the bullet or slug.
Receiver 21 defines an axially elongated internal cavity 40 which slidably carries and supports the bolt assembly 50. Cavity 40 extends along the longitudinal axis LA between the open front end 18 in communication with the barrel chamber 36 for loading cartridges therein and a closed rear end 19 defined by vertical rear end wall 43. Barrel 22 is coupled to the front end 18 of the receiver. In one non-limiting embodiment, the receiver 21 includes an axially elongated right ejection port 44 through which spent cartridge casings are ejected from the firearm after firing by ejector 45 (see, e.g.
For convenience of assembly and maintenance/repair, the firing mechanism 23 may be housed in trigger housing 23-1 best shown in
The firing mechanism 23 may include the following components mounted in the trigger housing 23-1: a pivotable and cockable hammer 25; pivotable sear 26 which is configured and operable to hold the hammer in a rear cocked position (see, e.g.
Bolt 50 has an axially elongated block-like body of generally rectilinear (e.g. rectangular cuboid) shape having a monolithic unitary structure. Front end 52 of bolt 50 defines the vertical breech face that engages the breech end 38 of the barrel 22 adjacent the cartridge chamber 36 when the breech is closed.
A bolt handle-recoil spring assembly is coupled to the bolt 50 to manually cycle the bolt between its forward and rearward positions by hand. Bolt 50 is also automatically moved under recoil forces between the forward and rearward positions when the action is cycled after discharging the firearm to eject a spent cartridge casing and chamber a new fresh cartridge. Cavity 40 of receiver 21 therefore has an axial length sufficient to provide the full range of motion necessary for the bolt assembly 50 moving rearward under recoil to open the breech for extracting and ejecting a spent cartridge casing, and uploading a new cartridge into the barrel chamber 36 from the magazine 33.
The bolt handle assembly comprises transversely oriented cocking handle 51. Handle 51 has a transversely elongated body which is received and nests at least partially in an upwardly open transverse socket 52-1 formed proximate to the front end 52 of the bolt 50. The operating end of the handle 51 may include a cylindrical knob for grasping or have another shape such as a curved bar configured for engaging a finger. The opposite spring seating end 51-2 of handle 51 is coupled to a recoil spring guide rod and seats one end of a recoil spring (not shown) which automatically returns the bolt 50 forward.
Referring to
The free-floating barrel mounting system with balanced moment forces which enhances shooting accuracy will now be described in further detail.
Referring generally to
Receiver 21 includes a lower cantilevered forward extension 214 arranged below the barrel mounting hole 210 beneath the barrel 22. The forward extension 214 extends axially parallel to but below the longitudinal axis LA of the firearm. Forward extension 214 cradles and supports the rear end of barrel 22. In one embodiment, the forward extension 214 of receiver 22 defines an upward facing and arcuately curved concave barrel support surface 215 which is radiused from side to side to complement the outer cylindrical shape of the barrel forward of the smaller diameter cylindrical breech end 38 in configuration (this portion of the barrel remaining outside barrel mounting hole 210 in the receiver). This provides conformal contact between barrel and receiver forward extension 214 when the barrel is fully inserted into the receiver. Support surface 215 is concentric with barrel mounting hole 210 in the receiver.
As shown in
In order to secure the barrel 22 to the receiver 21, the free floating barrel mounting system includes an upper above barrel bore centerline mounting feature in addition to a lower below bore centerline mounting feature. Without the above bore mounting feature, or alternatively contact with and support by the stock which would negate forming a free floating barrel mounting system and its inherent benefits, the barrel would be biased downward which may not fully optimize shooting accuracy.
Referring generally to
The forward extension 214 of receiver 21 has a truncated convex wedge end 217 formed by a pair of converging bearing surfaces 218 separated by a vertical bearing surface 219 in a similar vane to clamping block notch 222. Wedge end 217 is complementary configured to V-notch 222 of the clamping block. A pair of laterally spaced threaded axial holes 220 are formed in forward extension 214 of receiver 21 which receive threaded fasteners 201. Threaded holes 220 in forward extension 214 are concentric to unthreaded through bores 209 in clamping block 200.
To complete the lower barrel mounting feature, a transversely extending channel 205 is recessed into the bottom surface of barrel 22 which receives the upper portion of clamping block 200 therein as shown in
To secure the barrel 22 to receiver 21 via clamping block 200, the cylindrical rear breech end 38 of the barrel is inserted into the barrel mounting hole 210 in the front end of the receiver if not already done so. Securement fasteners 201 are inserted completely through the block to threadably engage their respective axial holes 220 in the receiver forward extension 214. The fasteners tightly draw the clamping block 200 into engagement with the barrel bearing surface 221 in channel 205 and the truncated wedge end 217 of the forward extension 214. This in turn tightly draws the barrel external shoulder 212 at the rear portion of the barrel against the flat front face 211 of the receiver 21 to secure the connection, thereby abutting rear annular face 213 against the barrel to the receiver front face. The interface between all of the foregoing mating angled bearing surfaces 207, 218, and 221, and front face 211 and rear face 213 is one of flat-to-flat.
Referring generally to
The foregoing recessed bearing surface 204 of barrel 22 is a preferred but not limiting construction since it allows for a compact interface with the receiver 21, and furthermore does not interfere with the forward cantilevered extension of the rail section 223 atop the receiver 21 which protrudes over the rear portion of the barrel (see, e.g.
In order to access the head of the securement fastener 202 for inserting and tightening the fastener (or conversely for loosening and removing the fastener), a forwardly open access passage 224 may be formed on the underside of the rail section 223 to access the threaded axial bore 203 of receiver 21, as shown in
To facilitate insertion and entry of the enlarged head of upper securement fastener 202 into the securement recess 206 on top of barrel 22 from the front, an arcuately curved concave lead-in chamfer 225 may be provided which communicates with the recess (see, e.g.
In one embodiment, the recess 206 in the top surface of barrel 21 may have a rectilinear configuration in top plan view, such as square or rectangular (see, e.g.
To secure the barrel 22 to the receiver 21 using the upper barrel mounting feature, the cylindrical rear breech end 38 of the barrel is first inserted into the barrel mounting hole 210 in the front end of the receiver if not already done so. Securement fastener 202 is then inserted through access 224 in rail section 223 and threadably engaged with threaded axial bore 203 formed in the front face 211 of receiver 21. This positions the enlarged head of securement fastener 202 into securement recess 206 (see, e.g.
It bears noting that the top securement recess 206 of barrel 22 is located entirely beneath the top rail section 223 of receiver 21 when the breech end 38 of the barrel is fully inserted into the barrel mounting hole 210 of the receiver (see, e.g.
With continuing reference to
In one embodiment, as shown, it bears noting that the upper securement fastener 202 is preferably centered over the top surface of the barrel 22 and the barrel mounting hole 210 of the receiver 21 equidistance between the sides of the receiver. The vertical reference plane VR intersects the upper securement fastener 202 and the longitudinal axis LA, and further falls equidistant between the two laterally spaced apart lower securement fasteners 201 (see, e.g.
When viewed looking rearward along the barrel towards its breech end 38 as seen in
A process or method for coupling a firearm barrel 22 to receiver 21 according to the present disclosure will now be briefly summarized with reference to
The user first axially aligns the barrel 22 with the receiver 21. The breech end 38 of the barrel is then slidably inserted rearward into barrel mounting hole 210 in the front end 18 of the receiver until the external shoulder 212 (rear surface or face 213) of the barrel abuttingly engages the front surface or face 211 of the receiver. Clamping block 200 is then inserted into the downwardly open bottom transverse channel 205 of the barrel 22, and engaged with the receiver forward extension 214 by inserting its front truncated wedge end 217 into the V-shaped notch 222 of the block 200. The lower securement fasteners 201 are then inserted rearward through the block 200 and threadably engaged with the receiver 21. Fasteners 201 are tightened to draw the block 200 into full engagement with the barrel and receiver, thereby clamping and compressing the lower rear portion of the barrel 22 against the receiver below the bore centerline of the barrel.
Next in the coupling process or method, the upper securement fastener 202 is then inserted rearward through access 224 in rail section 223 and threadably engaged with threaded axial bore 203 formed in the front face 211 of receiver 21. This concurrently positions the enlarged head of securement fastener 202 into securement recess 206 on the top of the barrel (see, e.g.
In some embodiments, the upper securement fastener 202 may instead be installed before the lower securement fasteners 201. The order is not limiting of the invention.
After the barrel 22 has been coupled to the receiver 21, the stock 80 may be secured to the barrel-receiver assembly by installing and threading the takedown screws 21-1 through the stock into their respective threaded sockets 216 in the bottom of the receiver 21. This completes fully assembly of the firearm 20.
Notably, as seen in
While the foregoing description and drawings represent preferred or exemplary embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope and range of equivalents of the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. In addition, numerous variations in the methods/processes as applicable described herein may be made without departing from the spirit of the invention. One skilled in the art will further appreciate that the invention may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims and equivalents thereof, and not limited to the foregoing description or embodiments. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the invention, which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention.
