US20170321978A1

US20170321978A1 - Tactical rifle

Info

Publication number: US20170321978A1
Application number: US15/147,270
Authority: US
Inventors: Stephen Ross Brannan; Kevin Michael Collins; David Irvin Brosey; Thomas Mooty; Charles Andrew Moore; Jeffrey McDonald; Harold L. Miller; Hollis Pettit Snead, III; Olivier Holger Costet
Original assignee: FN America LLC
Current assignee: FN Herstal SA
Priority date: 2016-05-05
Filing date: 2016-05-05
Publication date: 2017-11-09

Abstract

A tactical combat rifle includes a two-part, bolt carrier. The upper part of the bolt carrier rides on rails formed in an upper receiver while the lower part of the bolt carrier, although attached to the upper part and moving with it, engages no supporting surfaces. A piston, driven by combustion gases from a regulatable gas block assembly, strikes the upper bolt carrier in the center of its mass to propel it rearward. The barrel is threaded to a removable barrel extension and secured to the upper receiver. A non-reciprocating charging handle is located far forward and accessible from either side of the upper receiver so the user does not have to lower the rifle from the shoulder or take eyes off the target. Combustion debris is kept away from the lower receiver and bolt so operation is cleaner and cycling rates of fire steadier.

Description

TECHNOLOGICAL FIELD

The technological field of the disclosed tactical combat rifle is the field of small arms. More particularly, the technological field is rifles configured for use in a variety of combat situations.

BACKGROUND

Rifles have been the dominate small arm in combat for at least 200 years. In that time, they have evolved to be more accurate, lighter, and able to fire ammunition farther and at a higher rate.
Rifles have also evolved as a weapons platform from the time they were first designed to carry a bayonet. Present day rifles may carry additional equipment, such as sighting devices, laser markers, and additional weapons such as grenade launchers.
Rifles can operate quieter by using suppressors, may be less visible by using flash hiders, and more comfortable because of reduced weight, improved adjustability, and buffered butt stocks.
The capabilities of rifles as a weapons platform may overshadow how sophisticated they are from a purely mechanical point of view, that is, how their various parts cooperate together in the blink of an eye to use the pressure wave from firing a round of ammunition for rapidly and precisely reloading the rifle.
Yet there is room for improvement. Rifles may be used for different purposes in combat, such as perimeter defense, close quarter engagements, sniping, and assaulting an enemy force. Rifles are often used in physically hostile places, where they will come in contact with cold or hot weather, dirt, sand, mud, and vegetation. Rifles may now be expected to fire more rounds over their useful life and in all types of weather and environmental conditions. All of these factors challenge designers of tactical combat rifles to produce a safer, more reliable, more flexible and more durable rifle.

SUMMARY

The present tactical rifle includes a large, two-part, bolt carrier. The upper part of the bolt carrier rides on rails formed in the insides of an upper receiver, while the lower part of the bolt carrier is suspended from the upper part, and does not ride on its own supporting surfaces. The upper and lower parts of the bolt carrier move together smoothly and as one unit.
The bolt carrier is propelled rearward by a piston that is driven rearward by the pressure of combustion gases released on firing a round of ammunition. The piston strikes the bolt carrier in its center of mass for efficient and smooth action. Using a field-adjustable regulator, combustion gas available to the gas block assembly for movement of the bolt carrier may be adjusted by the user to vent a portion of the combustion gas to the atmosphere if a suppressor is attached to the barrel or to vent less gas when the rifle is being used in dusty conditions. The ability of the user to regulate gas pressure allows the cycling rate to be maintained despite changing operational circumstances.
The barrel of the present rifle is held to the receiver by a barrel extension. Two screws and a recoil lug hold the barrel extension securely in place. Removal of the two screws enables the user to replace the barrel or select a different barrel. If desired, the user can select a different barrel, different caliber ammunition, and the corresponding bolt for that ammunition.
The bolt area is kept cleaner by the present design. For example, the bolt is not unlocked from the chamber after a round has been fired until the pressure in the chamber has declined to near ambient pressure conditions so that little combustion particulate will be blown from the chamber when it is opened onto the end of the bolt and into the lower receiver. Furthermore, the gas block is positioned well forward of and above the bolt so debris from the gas block is also kept away from the bolt and lower receiver.
The rifle has a non-reciprocating charging handle, mounted farther forward on the upper receiver on either side of the upper receiver so as to be operable by both left- and right-handed shooters, and sufficiently far forward so that the shooter can continue to sight a target, the rifle continuing to remain on the shooter's shoulder while the user charges the gun.
These and other features and their advantages will be apparent to those skilled in the art of tactical rifle design from a careful reading the Detailed Description accompanied by the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures,

FIG. 1 shows a right side, exterior view of the present tactical rifle, according to an aspect of the disclosure;

FIG. 2 shows a right side, cross-sectional view of the tactical rifle of FIG. 1 with the bolt closed, according to an aspect of the disclosure;

FIGS. 3A and 3B are smaller scale views of the right side, cross-sectional view of the tactical rifle of FIG. 2, with FIG. 3A showing the rear portion of the rifle of FIG. 2 and with FIG. 3B showing the forward portion of the rifle of FIG. 2, according to an aspect of the disclosure;

FIGS. 4A and 4B show right side, cross-sectional views of the rifle of FIGS. 3A and 3B, respectively, with the bolt carrier fully recoiled after firing a round of ammunition, according to an aspect of the disclosure;

FIG. 5 shows a right side, cross-sectional view of the forward end of the rifle of FIG. 3B with the charging handle pulled rearward, according to an aspect of the disclosure;

FIGS. 6A and 6B show right side, cross-sectional views of rifle of FIGS. 2A and 2B, respectively, with the bolt just released from the chamber after firing the rifle, according to an aspect of the disclosure;

FIG. 7 is a cross-sectional of the upper receiver showing the rails from which the bolt carrier and charging sled are supported, according to aspects of the disclosure;

FIG. 8 is a perspective view of charging sled, according to an aspect of the disclosure;

FIG. 9 is a side view of the catch, according to an aspect of the disclosure;

FIGS. 10A and 10B are left front perspective and left side cross-sectional views of an attachment for a gas block to the barrel, according to an aspect of the disclosure;

FIGS. 11A, 11B, and 11C show a left rear perspective view, a left side cross-sectional view, and rear end, partial cross-sectional view of a gas regulator, according to aspects of the disclosure.

FIGS. 12A, 12B, 12C, and 12D show a left front perspective view, a front cross-sectional view, a left side exterior view, a left side cross-sectional view of lower bolt carrier, respectively, according to aspects of the disclosure;

FIG. 13 is a rearward, right side view of bolt without the extractor, according to an aspect of the disclosure;

FIGS. 14A and 14B show a side exterior view of an extractor and a perspective view of extractor threaded pivot pin, according to an aspect of the disclosure;

FIG. 15 is a right side exterior view of the cam pin of the bolt, according to an aspect of the present disclosure;

FIGS. 16A, 16B, 16C, and 16D show a rear right perspective view, a rear view, and a right side cross-sectional view of the barrel extension, and a perspective view of the recoil lug, according to aspects of the disclosure; and

FIGS. 17A and 17B show perspective and side views of the limit pin, according to aspects of the disclosure.

DETAILED DESCRIPTION

Herein is disclosed a rifle, referred to as a tactical combat rifle because of its capability to be altered for different uses in a combat environment. It is a combat rifle, primarily, being designed for fighting an enemy under difficult conditions and to fire a large number of rounds of ammunition dependably and in semi-automatic or fully automatic mode over an extended lifetime as a firearm.
FIG. 1 shows the present rifle, generally referred to by reference number 10, from the right side according to the perspective of a shooter holding the rifle in a right-handed firing position. A right-handed shooter tucks a buttstock 14 of rifle 10 into his or her shoulder, places the fingers of a right hand around a pistol grip 18, which is part of a lower receiver assembly 22, and an index finger on trigger 26 inside trigger guard 30 just behind a magazine 34 that is inserted in a magazine well 38. The right-handed shooter would extend his or her left arm forward along the left side of rifle 10 to support its distal end, the distal end being the end opposing the proximal end that is nearer to shooter, and would point the distal end of a barrel 42 at a target.
A significant difference in rifle 10 that is readily noticeable from the exterior is a long upper receiver 46. Upper receiver 46 encloses much of barrel 42 and may be made of a light-weight but sturdy material, such as aluminum. An aluminum upper receiver 46 may be extruded and then machined to complete the details of its construction.
FIG. 2 shows rifle 10 in a cross-sectional side view. In that cross-sectional view, the details of the interior structure include, from the left or proximal end of rifle 10, a bumper 50, an operating group spring 54, an operating rod 58, and a buffer 62. Buffer 62 receives the recoil of a bolt carrier 66 following the firing of a round of ammunition. Bolt carrier 66 is driven rapidly rearward, that is, to the left or proximal end of rifle 10 as shown in FIG. 2, thereby compressing operating spring 54. Operating spring 54 is then relieved as the force on buffer 62 dissipates. The recoil of bolt carrier 66 is absorbed largely by the resiliency of spring 54 and bumper 50 rather than by the shooter.
Forward of buffer 62 is lower receiver assembly 22 which includes a pistol grip 18, a trigger 26, a trigger guard 30, a magazine well 38, and a sear 68. A magazine 34 is shown in magazine well 38.
Upper receiver 46 is also shown in a transverse cross-sectional view in FIG. 7, which shows the interior 44 of upper receiver, including first rails 78 and second rails 104. Bolt carrier 66 is supported by second rails 104. As will be described further below, barrel 42 is supported by first rails 78.
Bolt carrier 66 includes both an upper bolt carrier 70 and a lower bolt carrier 74. Upper bolt carrier 70 and lower bolt carrier 74 are attached firmly together, such as by brazing at their interface at 72, seen in FIG. 4A, so they move together throughout the firing cycle. Upper bolt carrier 70 rides on second rails 104 in upper receiver 46. The weight of lower bolt carrier 74 is completely supported by upper bolt carrier 70 on second set of rails 104. Although lower bolt carrier 74 carries a bolt 82, a firing pin 86, and a cam pin 182 (best seen in FIG. 16), upper bolt carrier 70, being very long, provides the support required to carry lower bolt carrier 74 through its firing cycle.
FIGS. 3A and 3B show a smaller scale version of FIG. 2, dividing rifle 10 into separate rearward (FIG. 3A) and forward (FIG. 3B) portions. At the forward end of upper receiver 46 is a charging handle 94. Charging handle 94 may be operated using the shooter's preferred hand from the exterior of rifle 10. FIG. 3B shows rifle 10 having a charging handle 94 that is accessible from the left side for a right-handed shooter. Interior to receiver 46, but visible through a long slot 48 formed in receiver 46 (the right side of rifle 10 being symmetric to the left side with respect to charging operations) is a charging sled 98, which is shown in perspective from the right rear in FIG. 8. Charging sled 98 has opposing downward depending legs 100 that ride on second rails 104 toward the top of upper the interior 44 of receiver 46, as best seen in FIG. 7.
Charging sled 98 temporarily connects charging handle 94 to upper bolt carrier 70. As seen in FIG. 5, pivoting catch 102 (shown in detail in FIG. 9) on charging sled 98 is biased downward by a spring about pivot pin 106 but hooks the top of bolt carrier 70 when bolt carrier 70 is out of battery and then is pivoted upward again by camming pin 110 to release bolt carrier 70 when charging handle 94 is returned to its forward position, shown in FIG. 3B. Compare also FIG. 4B, in which charging handle 94 is in its rearward most position, and FIG. 6B, in which charging handle 94 is nearly in its forward-most position. Otherwise, charging handle 94 moves independently of upper receiver 46 and only pivots catch 102 when the user moves charging handle 94 rearward.
Upper bolt carrier 70 and lower bolt carrier 74 move rearward as a unit and far enough when rifle 10 is being charged so that bolt 82 ejects a spent shell casing through an ejection port 190 (see FIG. 1) on the right side of rifle 10. Then, as the operator moves charging handle 94 forward or releases charging handle 94, thereby allowing operating spring 54 to move bolt 82 forward, bolt 82 pushes a new round out of magazine 34 and into chamber 80 of barrel 42.
Once returned to its forward position, catch 102 is forced to pivot clockwise on engagement with a camming pin 110 which forces the distal end of catch 102 clockwise. Camming pin 110 thus prevents charging sled 98 and charging handle 94 from reciprocating with bolt carrier 66 during the firing cycle.
The forward location of charging handle 94 enables the operator of rifle 10 to maintain focus on a target while reaching forward with a support hand to operate it. Use of charging handle 94 obviates the need to take rifle 10 off the user's shoulder or the user's eye off a target. The user can maintain the target in sight while reaching forward with his support hand to grasp charging handle 94 on whichever side of rifle he has changing handle 94 installed, with charging handle 94 easily within the peripheral vision of the shooter when the shooter elects to charge rifle 10. Charging handle 94 also serves as a forward assist to push ammunition into chamber 80.
Except for movement of bolt carrier 66 using charging handle 94, bolt carrier 66 is otherwise moved by a gas block assembly located in the distal end of upper receiver 46 where it is positioned at a distance from lower receiver 22 and lower bolt carrier 74, so that these critical components are less likely to be subject to the combustion gas and debris from the barrel. See FIGS. 3B, 4B, 5, 10A, 10B, 11A, 11B, 11C, 12A, 12B and 12C. The gas block assembly includes a piston 114 (see FIGS. 3B, 4B, and 5), a barrel attachment 122 (FIGS. 10A and 10B), and a regulator (FIGS. 11A, 11B, and 11C).
Barrel attachment 122 surrounds and is secured to barrel 42. Barrel attachment 122 enables the interior of gas block 118 to communicate with the interior of barrel 42 through a passage 134 in barrel attachment 122 and a hole 146 in barrel 42 (best seen in FIGS. 3B, 4B, 5 and 6B). When passage 134 and hole 146 are in registration, a portion of the combustion gases that have been released by the firing of a round of ammunition pass from the interior of barrel 42 to the interior of gas block 118 where they are available to provide the back pressure required for moving piston 114 and thus bolt carrier 66 rearward against operating group spring 54.
FIG. 10A shows a perspective view of barrel attachment 122 from the left front, and FIG. 10B shows a left side, cross-sectional view of barrel attachment 122. Barrel attachment 122 has a lower portion 142 and an upper portion 150. Barrel 42 has a step 138 in its diameter at its distal end just posterior of the location of hole 146 (see FIG. 3B). Lower portion 142 of barrel attachment 122 has an interior 144 dimensioned to receive barrel 42 just proximal of step 138 so that hole 146 in barrel 42 may be aligned and be placed in registration with passage 134 from lower portion 142 into upper portion 150 of barrel attachment 122. Upper portion 150 receives gas block 118 (best seen in FIGS. 11A, 11B, and 11C) into an interior 154 of upper portion 150 of barrel attachment 122 and, accordingly, the interior of barrel 42 is then in fluid communication with channel 154. Gas block 118 is thus secured indirectly to barrel 42 by barrel attachment 122 and upper portion 150 of barrel attachment 122 and gas block 118 define channel 154. A portion of combustion gases traveling down barrel 42 toward its distal end are thus received in channel 154 via hole 46 in barrel 42 and passage 134 in barrel attachment 122 and are then used to provide the back pressure for operating bolt carrier 66.
The upper part 150 of barrel attachment 122 and gas block 118 are received in upper receiver 46. Piston 114 fits into upper part 150 of barrel attachment 122 but extends rearwardly outside barrel attachment 122 in line with upper bolt carrier 70. The axial range of motion of piston 114 relative to barrel attachment 122 is limited, as can best be seen by comparing the position of piston 114 in channel 154 in FIG. 3B, before firing, and in channel 154 in FIG. 4B, after firing, which show that an annular collar 152 on piston engages the narrowed end of channel 154 of barrel attachment 122 on the rearward end of its travel which is a channel 156 of gas block 118 (FIG. 11A). Accordingly, when a round of ammunition is fired, combustion gases pass down barrel 42 and through hole 146 of barrel 42, through passage 134 of barrel attachment 122, and into channel 154 where, on the build-up of sufficient pressure forward of labyrinth seals 116, the gas pressure impels piston 114 rearward in channel 154 so its distal end strikes upper bolt carrier 70, thus driving bolt carrier 70 rearward with sufficient force for it and lower bolt carrier 74 to perform their cycling function.
Referring now to FIGS. 11A-11C but particularly FIG. 11B, which shows regulator 130 in cross section, the distal end of channel 154 of barrel attachment 122 communicates with a channel 156 in regulator 130 which is threadedly received in barrel attachment 122. Channel 156 has two vents, namely, vent 170 and vent 174. Regulator 130 allows adjustments to be made by the user in the amount of combustion gas used to drive piston 114 by regulating the amount of combustion gas vented through either vent 170 or vent 174 or not vented at all. The adjustments are made by manually altering the rotational, or azimuthal, position of regulator 130 with respect to barrel attachment 122 so that combustion gas can flow out smaller vent 170, larger vent 174, or not flow from any vent. When no gas is vented, there is more back pressure to drive piston 114 rearward; when more gas is vented, less back pressure is available. By selecting the right choice of vent or no vent, the cycling rate of rifle 10 may be maintained within design range.
The first selection is the intermediate vent 170 for normal cycling operation, whereas vent 174 is selected for use with a suppressor on rifle 10. A suppressor attached to barrel 42 increases back pressure in barrel 42 and thereby increases the cycling rate of fire. Therefore, larger hole 174 is selected to offset that greater backpressure caused by a suppressor and thereby provide a more normal back pressure level to maintain the firing rate. The use of no hole may be reserved for circumstances when additional back pressure may be needed to overcome resistance to the movement of bolt carrier 66, such as when rifle 10 is in use in a dusty or dirty environment.
The choice of no vent, vent 170 and 174 is made by rotating regulator 130 to select the appropriate position. The hexagonal sides of regulator 130 may be marked to indicate which level of venting has been selected. The marking may include “Suppressed,” “Unsuppressed,” and “Adverse” (or abbreviations of these) for the choice of vent 174, 170, and no venting, respectively.
Referring now to FIGS. 12A-12D, lower bolt carrier 74 is shown. Lower bolt carrier 74 carries bolt 82 and firing pin 86, which are best seen in FIG. 3A; and bolt 82 is best seen in FIG. 13. FIG. 12A shows a perspective view of lower bolt carrier 74. FIG. 12B is a cross-sectional view of lower bolt carrier 74 to show a transverse hole 164 for a limit pin 168. Limit pin 168 is shown in perspective in FIG. 17A and in a side view in FIG. 17B, while transverse hole 164 is also seen in FIGS. 12A-12D but is also shown in relation to firing pin 86 in FIGS. 3A and 4A. Limit pin 168 has a thinner portion 126 that engages annular flanges 90 on firing pin 86 that limit axial movement of firing pin 86 within lower bolt carrier 74. FIG. 12C is a side view of lower bolt carrier 74 showing the shape of a cam path 178, which is on the side of lower bolt carrier 74.
Bolt 82, as shown in FIG. 13, includes a transversely mounted cam pin 182, which is shown in FIG. 14. Cam pin 182 is a cylindrical pin with a flattened extension 172 that passes through a transverse hole 176 (see FIGS. 3A, 4A, 6A) in bolt 82 thereby extending through cam path 178 in lower bolt carrier 74. Cam pin 182 also has a transverse hole 180 through which firing pin 86 passes so that, as lower bolt carrier 74 reciprocates, bolt 82 can rotate about the major axis of bolt carrier 74, guided by the movement of flattened extension 172 in cam path 178. As lower bolt carrier 74 moves through upper receiver 46, cam pin 182 rides on second rails 78 which forces bolt 82 to rotate through an angle when bolt carrier 74 moves to its forward-most position and flattened extension 172 moves through cam path 178. The rotation of bolt 82 in the rearward direction unlocks bolt 82 from chamber 80 and extracts a spent shell casing from chamber 80. The rotation of bolt 82 when moving in the forward direction selects the next round from magazine 34 and inserts it into chamber 80.
The shape of cam path 178, and in particular, the vertical portion of cam path 178, is such that it provides increased dwell time thereby providing more time for chamber 80 pressure to drop closer to atmospheric pressure before bolt 82 is unlocked from chamber 80 and thus limits blow back of combustion gases and debris into lower receiver 22 and thereby prolongs the useful life of rifle 10.
Lugs 210 on the forward end of bolt 82 will line up with cutout portions 214 formed in the entrance to barrel extension 198 so that bolt 82 can travel freely in and out of barrel extension 198. Rotation of bolt 82 will lock bolt 82 in barrel extension 198 and is caused when cam pin 182 rides from one end of cam path 178 of lower bolt carrier 74 to the other, thereby, rotating bolt 82 first one way and then the opposite way, to lock and unlock bolt 82 in barrel extension 198. A flat head 218 on cam pin 182 rides in a channel form in the left side of upper receiver 46 to rotate bolt 82 as cam pin 182 moves through a small angle to line up lugs 210 with cutout portions 214 of barrel extension 198. Upon clearing cutout portions 214, lugs 210 rotate further to lock bolt 82 in barrel extension and seat a cartridge in chamber 80. At that point in the cycle, bolt 82 is in its locked position.
Bolt 82 includes an extractor 186, shown in FIG. 14A, which is pivotally attached to bolt 82 by a threaded screw 184, as best seen in FIG. 14B. Screw 184 is driven through a hole 188 in extractor when extractor 186 is positioned between a pair of opposing holes 192 in bolt 82, as best seen in FIG. 13. Threads on screw 184 help to hold extractor 186 to bolt 82. Extractor 186 is designed to be robust, with a large radius 196 to be better able to extract a large number of spent shell casings over time. Shell casings are ejected to the right side of rifle 10 through an ejection port 190 (see FIG. 1) past a deflector 194 that limits rearward ejection. Deflector 194 may be a molded part attached by a screw 196
Barrel 42 is held to upper receiver 46 by barrel extension 198. FIG. 16A is a perspective view of barrel extension 198 from the right rear; FIG. 10B is an end view of barrel extension 198; and FIG. 16C is a cross-sectional view of barrel extension 198, with barrel 42, as viewed from the left side of rifle 10. FIG. 16D is a recoil lug 220.
Barrel extension 198 has flanges 200, two on either side of it, that rest on grooves 78 (See FIG. 7) of upper receiver 46 for support. Recoil lug 220, in FIG. 16D and also in FIG. 16C, is similar to a washer but is an accurately ground and controlled structure that slides over the threaded, proximal portion of barrel 42 and mates against a shoulder 226 on barrel 42. Barrel extension 198 clamps recoil lug 220 onto barrel 42. Barrel extension 198, recoil lug 220, and barrel 42 all slide rearward in upper receiver 46 and recoil lug 220 seats against a shoulder 226 formed in barrel 42 (seen in FIG. 16C), which is its stopping point. Barrel extension 198 threads onto the proximal end of barrel 42 until it seats against recoil lug 220. Two screws 202 (see FIG. 2) threaded into holes 204 formed in barrel extension 198 secure it to barrel 42 and in place with respect to receiver 46. Holes 204 for screws 202 are slightly offset so that, when screws 202 are driven into holes 204, screws 202 tend to pull barrel 42 rearward against receiver 46.
An external cover 206 is secured to receiver 46 underneath and laterally of barrel extension 198. Cover 206 is held in place with one screw 208.
Similarly, removal of screws 202 allows barrel 42 to be removed. A shorter or longer barrel 42 may be substituted, as needed, by the user. If bolt 82 is also replaced, the caliber of ammunition may be changed as well. Accordingly, at the field level, rifle 10 may be customized for different operational purposes. For example, a shorter barrel 42 may be better suited for close quarter combat and a longer one for perimeter guard duty.
Especially for use in fully automatic mode, there is a horizontal blind passage 216 in the upper bolt carrier 70. Passage 216 may be filled with tungsten powder and welded closed to provide a means to mitigate “bolt bounce.” Bolt bounce occurs when bolt carrier 66 impacts barrel extension 198 in the firing cycle. Bolt carrier 66 will tend to bounce back and then is driven forward immediately by operating group spring 54. The tungsten powder in passage 216, however, will impact the end of distal end of passage 216 to counter the bounce in mitigation of carrier bounce. Eliminating dead bolt carrier bounce is important, especially in full automatic operation, because the bounce can cause a “failure to fire” event—when lower bolt carrier 74 bounces rearward far enough that firing pin 86 is not able to strike the cartridge primer.
Rifle 10 is piston-driven from the distal end of rifle 10 so all debris from combustion tends to remain away from the rear, where lower bolt carrier 74 and lower receiver assembly 22 are located. Piston 114 hits bolt carrier 66 at its center of its mass for greater transfer of momentum. Upper bolt carrier 70 then rides on rails 78 of upper receiver 46, directly in line with piston 114. That riding surface is longer because upper receiver 46 is longer, making the movement of upper bolt carrier 70 smoother and surer.
Thus, the arrangement of the present rifle 10 provides a smoother firing platform. The added mass of bolt carrier 66, the adjustability of butt stock 14, along with the added length of stroke and half inch thick 40 durometer polyurethane bumper 50 and the elimination of blow back from chamber 80 when bolt 82 is unlocked further smoothes operation and maintains a steadier cycling rate.
When introducing elements of the present disclosure or exemplary aspects or embodiment(s) thereof, the articles “a,” “an,” “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Although this disclosure has been described with respect to specific embodiments, the details of these embodiments are not to be construed as limitations.

Claims

What is claimed is:

1. A rifle, comprising:

a barrel having a distal end and a proximal end and a chamber formed in said proximal end and a bore formed from said chamber to said distal end of said barrel and a hole formed in said bore of said barrel,

a gas block assembly attached to said barrel, said gas block assembly having an interior in communication with said hole in said bore of said barrel;

a piston slidably carried by said gas block assembly, said piston movable between a proximal position and a distal position so that gas from said barrel travels through said hole in said barrel to said interior of said gas block assembly and drives said piston from said distal position to said proximal position;

an upper receiver having rails, said barrel being housed in said upper receiver;

an upper bolt carrier slidable on said rails of said upper receiver and in operating connection with said piston of said gas block assembly so that when said piston slides proximally and strikes said upper bolt carrier, said upper bolt carrier slides proximally in response thereto;

a lower bolt carrier supported by and slidable with said upper bolt carrier;

a bolt carried by said lower bolt carrier;

a firing pin carried by said bolt;

a lower receiver attached to said upper receiver and having

a trigger, and

a magazine well proximate to said trigger and dimensioned for receiving an ammunition magazine; and

a butt stock attached to said lower receiver.

2. The rifle as recited in claim 1, further comprising a barrel extension attached to said proximal end of said barrel, said barrel extension holding said proximal end of said barrel to said receiver.

3. The rifle as recited in claim 1, further comprising a regulator attached to said gas block having an adjustable vent with at least two positions, a first position wherein relatively more back pressure is delivered to said piston and a second position wherein relatively less back pressure is delivered to said piston.

4. The rifle as recited in claim 1, wherein said upper bolt carrier and said lower bolt carrier are fastened together.

5. The rifle as recited in claim 1, wherein said receiver has a charging handle operable from either side of said upper receiver.

6. The rifle as recited in claim 1, wherein said bolt rotates as it moves from its distal position to its proximal position and wherein said bolt rotates to unlock from said chamber after said pressure in said chamber has decreased.

7. A rifle, comprising:

a barrel having a distal end and a proximal end and a chamber formed in said proximal end and a bore formed from said chamber to said distal end of said barrel and a hole formed in said bore of said barrel, said proximal end of said barrel having a threaded exterior;

a barrel extension having a threaded interior dimensioned for receiving said proximal end of said barrel, said barrel extension having plural lugs;

a gas block assembly attached to said distal end of said barrel, said gas block assembly having an interior in communication with said hole in said bore of said barrel;

an upper receiver having first rails and second rails, said barrel being housed in said upper receiver, said lugs of said barrel extension being supported on said second rails of said upper receiver;

an upper bolt carrier slidable on said first rails of said upper receiver and in operating connection with said piston of said gas block assembly so that when said piston slides proximally on said first rails and strikes said upper bolt carrier, said upper bolt carrier slides proximally in response thereto;

a lower bolt carrier supported by and slidable with said upper bolt carrier;

a bolt carried by said lower bolt carrier;

a firing pin carried by said bolt;

a lower receiver attached to said upper receiver and having

a trigger, and

a butt stock attached to said lower receiver.

8. The rifle of claim 7, wherein said barrel extension has two holes formed therein and where said barrel is pulled rearward against said receiver when said two screws are inserted and tightened in said two holes.

9. The rifle of claim 7, wherein said upper receiver has a proximal end and a distal end, and wherein said rifle further comprises a charging handle carried by said distal end of said upper receiver.

10. The rifle of claim 9, wherein said charging handle is non-reciprocating.

11. The rifle of claim 7, wherein said bolt carries an extractor, said extractor being fastened to said bolt with a threaded pin.

12. The rifle of claim 7, wherein said bolt has a recess and a pair of opposing holes on opposing sides of said recess, and wherein said bolt includes an extractor dimensioned to be receivable in said recess, said extractor having a hole formed therein, and wherein said hole in said extractor and said opposing holes are threaded, and wherein said bolt includes a threaded pin in said opposing holes and said hole in said extractor.

13. The rifle as recited in claim 7, wherein said upper receiver further comprises a shell ejection port and wherein said rifle further comprises a shell deflector fastened to said upper receiver adjacent to said ejection port so that ejected shells are deflected by said shell deflector.

14. The rifle as recited in claim 7, wherein said gas block assembly further comprises a regulator having plural user-selectable positions, a position of said plural positions providing a different back pressure to said gas block assembly so that back pressure on said piston may be altered.

15. The rifle as recited in claim 7, wherein said upper receiver has a proximal end and a distal end, and wherein said upper receiver has a slot formed in said distal end and wherein said rifle further comprises:

a charging sled carried within said receiver on said first rails;

a charging handle attached to said charging sled and extending from within said upper receiver through said slot, said charging handle configured for a user to pull said charging sled between said proximal position and said distal position; and

a hook pivotally mounted to said charging sled and pivoting between a hooked position and an unhooked position, said hook being in said hooked position to pull said upper bolt carrier to said distal position after charging said rifle and being in said unhooked position when said rifle is operating in said firing cycle.

16. The rifle as recited in claim 15, wherein said upper receiver carries a spring biasing said hook in said unhooked position, when said charging sled is in said distal position.

17. The rifle of claim 7, wherein said bolt further comprises a cam pin and upper receiver has a cam path formed therein, said cam pin extending through said bolt and into said cam path, said cam pin following said cam path as said upper bolt carrier and lower bolt carrier move from a distal position to a proximal position and back to a distal position in a firing cycle, said cam path configured so that said bolt is not unlocked from said chamber until pressure in said chamber is reduced.

18. The rifle of claim 7, wherein said upper bolt carrier is brazed to said lower bolt carrier.

19. The rifle of claim 7, wherein said upper bolt carrier has a closed passage formed therein said passage containing a powder freely movable within said passage.

20. The rifle of claim 7, wherein said piston strikes said upper bolt carrier in the center of mass of said upper bolt carrier.