AUTOMATIC RIFLE AND RECEIVER FOR SAME

Abstract

An automatic rifle (10) includes a receiver (12), a bolt assembly (110), a trigger mechanism (106), a buttstock assembly (100), a barrel assembly (104), and a grip assembly (102). The receiver (12) is characterized by being a unitary body that houses the bolt assembly (110) and the trigger mechanism (106), and the receiver (12) is configured for the connection thereto of the buttstock assembly (100), the barrel assembly (104), and the grip assembly (102).

Claims

1. An automatic rifle comprising: a receiver; a bolt assembly; a trigger mechanism; a buttstock assembly; a barrel assembly; and a grip assembly; wherein the receiver houses the bolt assembly and the trigger mechanism; and wherein the buttstock assembly, the barrel assembly, and the grip assembly are connected to the receiver; and wherein the receiver is a unitary body that forms (a) a rear opening through which the bolt assembly is slidably removable in a backward motion, and (b) a magazine well having a magazine opening.

2. The automatic rifle according to claim 1, wherein the receiver has a front end, a rear end, and a lower end, and wherein the buttstock assembly is connected to the rear end of the receiver, the barrel assembly is connected to the front end of the receiver, the grip assembly is positioned at the lower end of the receiver, and the trigger mechanism is positioned below the bolt assembly.

3. The automatic rifle according to claim 1, wherein the bolt assembly comprises: a bolt; a bolt carrier; and a firing pin.

4. The automatic rifle according to claim 1, wherein the buttstock assembly comprises: a buffer; an action spring; and a buffer tube housing the buffer and the action spring; wherein the buffer tube is arranged to receive a rear portion of the bolt carrier during a cycling of the bolt assembly; wherein the buttstock assembly further has a buttstock adapter attached to the buffer tube and to the receiver at the rear opening of the receiver; wherein the buttstock adapter has a bolt carrier opening through which the rear portion of the bolt carrier passes and enters the buffer tube during the cycling of the bolt assembly; and wherein the buttstock adapter prevents the bolt assembly from being removed through the rear opening.

5. The automatic rifle according to claim 4, wherein the bolt carrier opening of the buttstock adapter is a through hole and has a female threading, the buffer tube has a proximal portion positioned in the bolt carrier opening, and the proximal portion has a male threading that cooperates with the female threading of the bolt carrier opening.

6. The automatic rifle according to claim 4, wherein the buttstock adaptor is releasably attached to the receiver.

7. The automatic rifle according to claim 4, wherein the buttstock adaptor further comprises a first pivot rotationally connecting the buttstock assembly to the receiver, wherein the buttstock assembly has a closed orientation relative to the receiver in which the bolt carrier opening is aligned with one of the rear portion of the bolt carrier and the rear opening of the receiver, and an open orientation at which the buttstock adapter allows the bolt assembly to be removed through the rear opening.

8. The automatic rifle according to claim 7, wherein the first pivot engages the receiver at a point below the rear opening of the receiver.

9. The automatic rifle according to claim 8, wherein the first pivot is arranged to rotate the buttstock assembly around an axis that is parallel to a cycling motion of the bolt carrier.

10. The automatic rifle according to claim 8, wherein the first pivot is arranged to rotate the buttstock assembly around an axis that is transverse to a cycling motion of the bolt carrier.

11. The automatic rifle according to claim 10, wherein the grip assembly forms part of the buttstock adapter, and the first pivot is located on, or connected to, the grip assembly.

12. The automatic rifle according to claim 1, wherein the trigger mechanism comprises: a trigger; a hammer operationally connected to the trigger; and a housing supporting the trigger and the hammer; wherein the receiver has a trigger housing seat in which the housing is positioned; wherein the trigger mechanism is releasably connected to the receiver; and wherein the trigger housing seat has a lower seat opening through which the housing can be slidably removed in a downward motion.

13. The automatic rifle according to claim 12, wherein the grip assembly is releasably attached to the receiver, and the grip assembly prevents the housing of the trigger mechanism from being removed through the lower seat opening.

14. The automatic rifle according to claim 12, wherein the grip assembly comprises a second pivot rotationally connecting the grip assembly to the receiver, and wherein the grip assembly has a closed orientation relative to the receiver in which it prevents the housing of the trigger mechanism from being removed through the lower seat opening, and an open orientation relative to the receiver at which the grip assembly allows the housing of the trigger mechanism to be removed through the lower seat opening.

15. The automatic rifle according to claim 1, further comprising: a safety mechanism below the bolt assembly, the safety mechanism comprising: a safety lever; and a safety biasing mechanism, wherein the safety biasing mechanism comprises: a safety detent; and a safety detent spring operationally connected to the safety detent, whereby the safety detent biases the safety lever; wherein the safety biasing mechanism as a whole is housed in the receiver; and wherein the safety detent spring is configured to provide a pushing force in a downward direction; and wherein the safety biasing mechanism further comprises: a detent lever pivotally supported relative to the receiver, whereby the safety detent spring is configured to act on the detent lever, and the detent lever is configured to provide a pushing force in an upwards direction that is transferred to the safety detent.

16. The automatic rifle according to claim 1, wherein the barrel assembly comprises: a barrel; and a barrel extension supporting the barrel; wherein the receiver has a front end in which is defined an extension hole, and the barrel extension is at least in part positioned in the extension hole; wherein the barrel assembly further comprises: a forward extension fixed relative to the receiver at the front end of the receiver, wherein the forward extension forms a screw hole having a female threading and is aligned with the extension hole of the receiver; and a barrel screw at least in part positioned in the screw hole and having a male threading cooperating with the female threading of the screw hole, the barrel screw engaging the barrel extension so as to press the barrel extension against the receiver.

17. The automatic rifle according to claim 16, wherein the receiver has an upper end and forms an accessory rail extending along at least a portion of the upper end and along the complete length of the forward extension.

18. The automatic rifle according to claim 16, wherein the barrel extension has a radial flange extending outwards, the barrel screw presses against the radial flange, and the flange engages the receiver at the distal end of the extension hole.

19. A receiver for an automatic rifle configured to house a bolt assembly and a trigger mechanism, and adapted to connect to a buttstock assembly and a barrel assembly, wherein the receiver is a unitary body that forms (a) a rear opening through which the bolt assembly is slidably removable in a backward motion, and (b) a magazine well having a magazine opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Different embodiments of the proposed technology are described below. References are made to the following figures, wherein:

[0083] FIGS. 1a to 1f are planar projections of an embodiment of a receiver;

[0084] FIGS. 2a and 2b are perspective views of the receiver shown in FIGS. 1a to 1f;

[0085] FIG. 3 is a perspective view of an embodiment of an automatic rifle with the receiver shown in the previous figures;

[0086] FIG. 4 is a cross-sectional view of the automatic rifle shown in FIG. 3;

[0087] FIGS. 5a to 5c are perspective views of the receiver, grip assembly, and buttstock assembly of the automatic rifle shown in FIG. 3, with the latter in different orientations relative to the receiver;

[0088] FIG. 6 is a perspective view of the rear end of the receiver and the grip assembly of the automatic rifle shown in FIG. 3;

[0089] FIGS. 7a and 7b are partly exploded and perspective views of the buttstock assembly and the rear end of the automatic rifle shown in FIG. 3;

[0090] FIGS. 8a to 8c show the insertion of the trigger mechanism in the receiver of the automatic rifle shown in FIG. 3 and the different orientations of the grip assembly;

[0091] FIG. 9 shows an alternative embodiment of an automatic rifle with different buttstock and grip assemblies;

[0092] FIG. 10 is a cross sectional view of a part of the automatic rifle shown in FIG. 3 showing its safety mechanism;

[0093] FIG. 11 is a partly exploded and perspective view of the barrel assembly of the automatic rifle shown in FIG. 3; and

[0094] FIG. 12 is cross-sectional view of a part of the rifle shown in FIG. 3 showings its trigger mechanism, grip assembly, and barrel assembly.

DETAILED DESCRIPTION

[0095] An embodiment of a receiver 12 for an automatic rifle 10 is shown in FIGS. 1a to 1f and in FIGS. 2a and 2b. It is intended to function with common components of AR-15 style rifles that are based on the ArmaLite AR-15 design.

[0096] The receiver 12 has a rear end 16, front end 18, upper end 20, lower end 22, a right side 24, and a left side 26. The orientations referred to here are with the rifle firing in a horizontal direction with the grip assembly positioned directly below the receiver.

[0097] The receiver has been manufactured by machining a single piece of aluminum alloy. The receiver forms a bolt way 14 (space indicated by the dashed lines in FIGS. 1b and 1d-1f) that can house a bolt assembly. The bolt way 14 is accessible from the outside via a rear opening 28 at the rear end 16, an extension hole 30 at the front end 18, and an ejection port 32 on the right side 24.

[0098] The receiver 12 forms a magazine well 34 located below the bolt way 14 that can receive a detachable box magazine (not shown). The space of the magazine well 34 is open to the bolt way 14. The magazine well 34 can be accessed from below via a magazine opening 36 at the lower end 22 of the receiver 12. The magazine is inserted via the magazine opening 36. The receiver 12 further has holes 38 for a magazine catch (not shown) that can releasably lock the magazine to the receiver 12. The minimum height of the receiver at the magazine well 34 is preferably about 100 mm.

[0099] The receiver 12 forms a trigger housing seat 40 located below the bolt way 14 and behind the magazine well 34. The trigger housing seat 40 can receive the housing of a trigger mechanism in which the housing supports the trigger and the hammer. The space of the trigger housing seat 40 is open to the bolt way 14. The trigger housing seat 40 can be accessed from below via a trigger opening 42 at the lower end 22 of the receiver 12. The trigger housing with the trigger and the hammer can be inserted via the trigger opening 42. Additionally, the receiver has first pin holes 62 and second pin holes 64 that can receive an inner trigger pin securing the trigger and an inner hammer pin securing the hammer, respectively, thus locking the housing of the trigger mechanism to the receiver 12. The minimum height of the receiver at the trigger housing seat 40 is preferably about 85 mm.

[0100] The receiver 12 further forms the abovementioned extension hole 30 at the front end 16 of the receiver 14. The extension hole 30 is smooth, through-going, and can receive a portion of a barrel extension that is part of a barrel assembly. The extension hole 30 has a cylindrical shape centered on the bore axis 46 of the barrel of the barrel assembly.

[0101] The receiver 12 also forms a forward extension 48 at the front end 16 of the receiver 14 having a screw hole 50 that is countersunk relative to the extension hole 30 and centered on the bore axis 46. The screw hole 50 has a female threading and can receive a barrel screw with cooperating male threading that engages the barrel extension and press it against the receiver 12. The screw hole 50 has a larger diameter than the extension hole 30, thus forming a ledge 52 between them. The barrel extension has an annular flange at its forward end that engages the ledge 52. The barrel screw has a through bore that is centered on the bore axis 46 when the barrel screw is installed in the screw hole 50, at which the barrel extends through the through bore. The receiver has a hole 66 through which a barrel extension pin can enter the extension hole 30 and enter a bore in the barrel extension for the purpose of orienting the barrel assembly with respect to the receiver 12.

[0102] The receiver forms a beam 88 that extends from a point at the well opening 36 of the magazine well 34 to a point at the front end of the screw hole 50 of the forward extension 48. The beam 88 is a planar triangular structure aligned with a vertical plane and parallel to the bore axis 46. It has a concave front edge 90 and connects to the receiver 12 along a vertical line at the front of the magazine well 34 and along a horizontal line at the lower end of the forward extension 48.

[0103] The receiver has holes 58 for a safety lever. The receiver 12 has a blind bore 54 at its lower end 22 that is at a right angle to the bore axis 46. The blind bore 54 can receive a safety-detent spring that provides a pushing force in a downward direction. The receiver 12 also has a cut-out 56 for a detent lever. The cut-out forms a through hole to the bolt way 14 that can house a safety detent acting on the safety lever. The safety-detent spring, the detent lever, and the safety detent jointly form a safety biasing mechanism that together with the safety lever form a safety mechanism, which is supported by the receiver 12.

[0104] As mentioned above, the receiver 12 has a rear opening 28 at its rear end 16 through which a bolt assembly can be slidably inserted or removed parallel to the bore axis 46. The bolt assembly is then housed in the bolt way 14 of the receiver 12. The receiver 12 forms a key way 70 that can receive a charging handle and in which a carrier key or carrier appendix can travel during the cycling of a bolt assembly. The key way 70 is a groove that extends parallel to bore axis 46 and is located at the upper end of the bolt way 14, or receiver 12. The key way 70, has a profile or transverse cross section that is smoothly curved, or it has a rounded profile at its upper end, or at the upper end of the receiver 12. It opens to the bolt way 14 at the lower, or opposed, end. The receiver 12 further forms a cut out 72 at its rear end 16 that can receive the end of the charging handle.

[0105] The receiver has a through-going gas-conduit bore 60 at its front end 18 and above the extension hole 30 through which the gas conduit of a direct impingement system enters the key way 70.

[0106] The receiver 12 has a pivot recess 74 that can form a first pivot with a pivot protrusion of a buttstock adaptor of a buttstock assembly. At its rear end 16, the receiver 12 forms a first receiver flange 76 at its right side 24 and a second receiver flange 78 at its left side 26 that can cooperate with a first adaptor flange and a second adaptor flange, respectively, formed by an adaptor body of the buttstock adaptor. The first receiver flange 76 and the second receiver flange 78 are located above the pivot recess 74. The receiver 12 further forms third receiver flanges 80 at the edge of the pivot recess 74 that can cooperate with pivot flanges of the abovementioned pivot protrusion.

[0107] The receiver 12 has pivot-pin holes 84 and lock-pin holes 86 that can receive a pivot pin and a lock pin respectively that attach a grip assembly to the receiver 12 at the lower end 22 of the receiver 12 and behind the magazine opening 36.

[0108] The receiver 12 forms an accessory rail 82 at its upper end 20 and that extends parallel to the bore axis 46. The accessory rail 82 extends along the complete length of the forward extension 48.

[0109] FIG. 3 is a perspective of an embodiment of an automatic rifle 10 with the previously described receiver 12 fitted with a buttstock assembly 100, grip assembly 102, and a barrel assembly 104. The barrel 94 has a male threading at its front end 96 on which a flash suppressor can be mounted. Additionally, the automatic rifle 10 is fitted with a forend 98 at the front end 18 of the receiver 12.

[0110] FIG. 4 is a through-cut of the assault rifle 10 further showing its trigger mechanism 106, safety mechanism 108, and a bolt assembly 110. The buttstock assembly 100 is connected to the rear end 16 of the receiver 12 and is positioned behind the bolt assembly 110. The barrel assembly 104 is connected to the front end 18 of the receiver 12 and is positioned in front of the bolt assembly 110. The grip assembly 102 is positioned below the receiver 21, thus also below the bolt assembly 110. The trigger mechanism 106 is positioned below the bolt assembly 110. The receiver 12 has the magazine well 34 located below bolt assembly 110 and in front of the grip assembly 102.

[0111] The bolt assembly 110 is slidably supported in the bolt way 14 of the receiver 12. The bolt assembly 110 has a rotationally lockable bolt 112, a bolt carrier 114, a firing pin channel 116 in which a firing pin (not shown) can be fitted, and a carrier key 118. The carrier key 118 is attached to the upper end of the bolt carrier 114. In the cycling of the bolt assembly 110, the bolt 112 and the bolt carrier 114 slide in the bolt way 14, and the carrier key 118 slides in the key way 70. A charging handle 120 is inserted in the key way 70 and engages the carrier key 118 at the front of the carrier key 118. The bore axis 46 is indicated by a dashed line and the bolt assembly moves parallel to this axis when cycling.

[0112] The buttstock assembly 100 has a buffer 122, an action spring 124, and a buffer tube 126 that houses the buffer 122 and the action spring 124. The buffer tube 126 has a rear end at which the action spring 124 rests. The action spring 124 engages the buffer 122 and biases the buffer 122 in a forward position inside the buffer tube 126. During a cycling of the bolt assembly 110, the bolt carrier 114 engages the buffer 122, and a rear portion of the bolt carrier 114 enters the buffer tube 126. The buttstock assembly 100 further has a buttstock adapter 128 attached to the buffer tube 128 and to the receiver 12 at the rear opening 28 of the receiver 12. A buttstock 130 is slidably attached to the buffer tube 126, and it can be locked at different positions along the buffer tube 126.

[0113] FIGS. 5a to 5c are perspective views of the buttstock assembly 100 in different orientations relative to the receiver 12. The buttstock assembly 100 is rotationally connected to the receiver 12 by a first pivot defined by the buttstock adaptor 128 and the receiver 12. FIG. 5a shows the buttstock assembly 100 in a closed orientation relative to the receiver 12, at which the bolt assembly 110 is prevented from being removed through the rear opening 28 of the receiver 12. FIG. 5b shows the buttstock assembly 100 in an open orientation relative to the receiver 12, at which the bolt assembly 110 can be removed through the rear opening 28 of the receiver 12. The buttstock assembly 100 reaches the open orientation from the closed orientation by a clock-wise rotation around an axis parallel to the bore axis 46, which is defined by the first pivot. In FIG. 5c the buttstock assembly 100 has been detached from the receiver 12 and is in a released orientation.

[0114] FIG. 6 is a perspective view of the rear end 16 of receiver 12 of the automatic rifle 10 showing the abovementioned pivot recess 74, first receiver flange 76, second receiver flange 78, and third receiver flange 80

[0115] FIGS. 7a and 7b are partly exploded and perspective views of the buttstock assembly 100 and the rear end 16 of the automatic rifle 10.

[0116] The buttstock adaptor 128 has a unitary adaptor body 134 machined from a single piece of an aluminum alloy. The adaptor body 134 forms a bolt carrier opening 132 that is aligned with the rear opening 28 and the bolt way 14 of the receiver 12 when the buttstock assembly 100 is in its closed orientation, as is shown in FIG. 5a.

[0117] The bolt carrier opening 132 is provided with a female threading and the buffer tube 126 has a front portion with a matching male threading. The front portion is located inside the bolt carrier opening 132 and engages its female threading. The rear portion of the bolt carrier 114 passes through the bolt carrier opening 132 and enters the buffer tube 126 during the cycling of the bolt assembly 110.

[0118] The carrier key 118 constitutes a transversely protruding portion of the bolt assembly 110 that cannot pass though the bolt carrier opening 132 when the buttstock assembly 100 is in its closed orientation relative to the receiver 12. In other words, the carrier key 118 causes the bolt assembly 110 to have a transverse extension in the vertical direction that is greater than the diameter, or transverse vertical extension, of the bolt carrier opening 132. This means that the buttstock adapter 128 prevents the bolt assembly 110 from being removed through the rear opening 28 of the receiver 12.

[0119] When the buttstock assembly 100 is in its open orientation relative to the receiver 12, as is illustrated in FIG. 5b, the adaptor body 134 has been rotated relative to the receiver 12 such that it no longer partly blocks the rear opening 28, whereby the bolt assembly 110, including the carrier key 118, can be removed through the rear opening 28 of the receiver 12 together with the charging handle 120.

[0120] The buttstock adaptor 128 has a buffer retainer 136 in the form of a spring biased detent supported in the adaptor body 134 and positioned in front of the bolt carrier opening 132. The buffer retainer 13 prevents the buffer 122 from leaving the buffer tube 126 through the bolt carrier opening 132 when the buttstock assembly 100 is in its open position relative to the receiver 12, or when it is removed from the receiver 12.

[0121] The adaptor body 134 of the buttstock adaptor 128 forms a first adaptor flange 146 and a second adaptor flange 148 on either side of the bolt carrier opening 132. Both adaptor flanges 146 and 148 have rims facing in the same general direction (left), as can be seen in FIG. 7b. The first adaptor flange 146 and the second adaptor flange 148 engage the first receiver flange 76 and the second receiver flange 78, respectively, when the buttstock assembly 100 is in its closed orientation relative to the receiver 12.

[0122] The adaptor body 134 further forms a pivot shaft 150 below the bolt carrier opening 132. The pivot shaft 150 has a pivot flange 152 at its forward end. In both the closed and open orientations of the buttstock assembly 100, the pivot shaft 150 and the pivot flange 152 are inserted in the pivot recess 74 at the rear end 16 of the receiver. The pivot flange 152 engages the third receiver flange 80 at the pivot recess 74 in these positions, which prevents the buttstock assembly 100 from moving backwards relative to the receiver 12 in both orientations.

[0123] The pivot shaft 150, the pivot flange 152, the pivot recess 74, and the third receiver flange 80 define the first pivot, which means that the first pivot engages the receiver 12 at a point below the rear opening 28 of the receiver 12, and that the buttstock assembly 100 is connected to the receiver 12 also in its open orientation.

[0124] The buttstock adaptor 128 has a spring biased first locking pin 138 with a truncated conical head at its rear end. The first locking pin 138 is supported at the rear end 16 of the receiver 12 in a first locking pin hole 140; see FIGS. 1d and 2d. The conical head of the first locking pin 138 engages a cylindrical portion of a first through bore 142 in the adaptor body 134 when the buttstock assembly 100 is in its closed orientation relative to the receiver 12. The base of the conical head has a greater diameter than the cylindrical portion, while its truncated tip has a smaller diameter then the cylindrical portion, thus locking the buttstock assembly 100 in its closed orientation.

[0125] The buttstock assembly 100 is released from the closed orientation by pressing the spring biased first locking pin 138 towards the receiver 12. This is achieved by pressing a spring biased first extension pin 144 supported in the first through bore 142 in the adaptor body 134, and the first extension pin 144 in turn engages and presses against the first locking pin 138. The buttstock assembly 100 can then be rotated from its closed position, as is shown in FIG. 5a, to its open orientation, as is shown in FIG. 5b. Alternatively to the first extension pin 144, the first locking pin may be engaged by a thin object, such as the tip of a bullet, via the first through bore 142.

[0126] The buttstock adaptor 128 has a spring biased second locking pin 154 with a flanged head at its rear end. The second locking pin 154 is supported in the pivot recess 74 and its flanged head cooperates with the third receiver flange 80 and the pivot flange 152. The buttstock assembly 100 is released from the open orientation by pressing the spring biased second locking pin 154 towards the receiver 12, whereby the buttstock assembly 100 can be removed from the receiver 12. This is achieved by pressing a spring biased second extension pin 158 supported in a second through bore 156 in the adaptor body 134. The second extension pin 158 in turn engages and presses against the second locking pin 154. The buttstock assembly 100 can then be changed from its open position, as is shown in FIG. 5b, to its released orientation, as is shown in FIG. 5c, in which it is completely disengaged from the receiver 12. This means that buttstock assembly 100 is releasably locked to the receiver 12 in both the closed and open orientations.

[0127] The buttstock adaptor 128 has a retainer washer 160 securing the spring biased first extension pin 144 in the first through bore 142 and the spring biased second extension pin 158 in the second through bore 156. The orientation of the retainer washer 160 relative to the adaptor body 134 is fixed by a retainer pin 162 at the rear end of the adaptor body 134 and a cooperating retainer pin hole 164 in the retainer washer 160.

[0128] The buttstock assembly may further have a rotation locker 166 in the form of a nut positioned on the proximal portion of the buffer tube 126 and cooperating with the male threading on the proximal portion. The rotation locker 166 presses against the retainer washer 160, which in turn presses against the adaptor body 134, thus fixing the retainer washer and preventing the buffer tube 126 from rotating relative to the adaptor body 134.

[0129] FIGS. 8a and 8b show the insertion of the trigger mechanism 106 in the receiver 12. The trigger mechanism 106 has a trigger 168, a hammer 170, and a disconnector 172 operationally connected to one another; see also FIG. 4. The trigger mechanism 106 further has a housing 174 and the trigger 168 and the disconnector 172 are rotationally connected to the housing 174 by a hollow trigger pin (not shown), and the hammer 170 is rotationally connected to the housing 174 by a hollow hammer pin (not shown). This way, the housing 174 supports and partly encloses the trigger 168, hammer 170, and disconnector 172.

[0130] As mentioned above in relation to FIGS. 1a to 1f, the receiver 12 forms a trigger housing seat 40 that can be accessed from below via a trigger opening 42 at the lower end 22 of the receiver 12. The housing 174 of the trigger mechanism is received in the trigger housing seat 40, as is illustrated in FIG. 8b.

[0131] The trigger mechanism 106 further has a pin assembly 176 formed by an inner trigger pin 178, an inner hammer pin 180, and a beam 182 rigidly connecting the inner trigger pin 178 and the inner hammer pin 180. The receiver 12 further has a first pin hole 62 and a second pin hole 64. The housing 174 of the trigger mechanism 106 is locked relative to the receiver by the inner trigger pin 178 being inserted in the first pin holes 62 and the hollow trigger pin (not shown), and by the inner hammer pin 180 being inserted in the second pin holes 64 and the hollow hammer pin (not shown), as is shown in FIG. 8b.

[0132] The grip assembly 102 has a grip base 184 forming a trigger guard. A pistol grip 186 is rigidly attached to the grip base 184. The grip base 184 is connected to the receiver 12 by a pivot pin 188 engaging the grip base 184 at its front end. The pivot pin 188 is oriented horizontally and transverse to the bore axis 46 and forms a second pivot by which the grip assembly 102 is rotationally connected to the receiver 12.

[0133] The grip assembly 102 has an open orientation relative to the receiver 12 in which the trigger mechanism 106 can be inserted in or removed from the trigger housing seat 40, as is shown in FIG. 8b.

[0134] The grip assembly 102 has a closed orientation relative to the receiver 12 in which the trigger mechanism 106 is prevented from being removed from the trigger housing seat 40 by the grip base 184 of the grip assembly 102, as is shown in FIG. 8c. In this orientation, the grip base 184 is locked to the receiver 12 by a lock pin 190 entering a lock pin hole 192 of the grip base 184 at the rear end of the grip base 184. The grip base 184 forms a trigger slit 194 in the upper end of the trigger guard through which the trigger 168 extends.

[0135] The grip base 184 has an upward extending portion 196 in the form of a pin extending along the left side 26 of the receiver 12. The upward extending portion 196 engages the beam 182 of the pin assembly 176 in the closed orientation of the grip assembly 102, thus securing the pin assembly 176 relative to the receiver 12.

[0136] An alternative embodiment of an automatic rifle 10 is shown in FIG. 9. This embodiment differs in that the first pivot has a pivot pin 198 arranged horizontally and transversely with respect to the bore axis. The grip assembly 102 form part of the buttstock adapter 128 and the pivot pin 198 engages and connects to the grip assembly at the front end of the grip assembly 102. The grip assembly 102 and the buttstock adaptor 128 are connected and jointly form a rigid structure. This way, the first pivot is arranged to rotate the buttstock assembly 100 around a transverse horizontal axis.

[0137] FIG. 10 is a cross sectional view of a portion of the automatic rifle 10 showing the internals of the safety mechanism 108. The safety mechanism 108 has a safety lever 200, see also FIGS. 3 and 8c, and a safety biasing mechanism 202. The safety biasing mechanism 202 has a safety detent 204 and a safety-detent spring 206 that is operationally connected to the safety detent 204 by way of a detent lever 208. The safety detent 204 and the detent lever form a unitary body. The safety biasing mechanism 202 as a whole is housed in the receiver 12.

[0138] The safety-detent spring 206 is a compression coil spring generating a downward force that is transformed to an upward force by the detent lever 208 that pushes the safety detent 24 against the safety lever 200.

[0139] The safety lever 200 has a first setting in which it engages the trigger 164 and prevents the trigger mechanism 106 from firing. The safety lever 200 further has a second setting in which it does not engage the trigger 164 or disconnector 172, whereby the trigger mechanism 106 can fire a single shot when the trigger 164 is pulled. The safety lever 200 has a first recess 210 that receives the safety detent 204 in the first setting and a second recess 212 that receives the safety detent 204 in the second setting. This way, the safety lever 200 is biased in the respective settings.

[0140] FIG. 11 is a partly exploded and perspective view of the barrel assembly 104 of the automatic rifle 10, and FIG. 12 is a cross-sectional view of the rifle 10 showings its receiver 12, trigger mechanism 106, grip assembly 102, and barrel assembly 104.

[0141] The barrel assembly 104 has a barrel 94 and a barrel extension 214 supporting the barrel 94. As mentioned above, the receiver 12 forms a through-going extension hole 30 at its front end 18. The rear portion of the barrel extension 214 has an outer smooth cylindrical shape that matches the smooth cylindrical shape of the extension hole. This way, the rear portion of the barrel extension closely fits in the extension hole 30.

[0142] The receiver 12 further forms a forward extension 48 of the barrel assembly 104 at the front end 18 of the receiver 12, which means that the forward extension 48 is fixed relative to the rest of the receiver 12. The forward extension 48 forms a screw hole 50 with a female threading. The combined length of the extension hole 30 and the screw hole 50 is 55 mm.

[0143] As mentioned above, the screw hole 50 has a larger diameter than the extension hole 30, and the receiver 12 thus forms a ledge 52 therebetween. The barrel extension 214 has a radial flange 220 that extends outwards and engages the ledge 52 at the front end of the extension hole 30.

[0144] The barrel assembly 104 further has a barrel screw 218 with a rear portion positioned in the screw hole 50 and having a male threading cooperating with the female threading of the screw hole 50. The threadings of the screw hole 50 and the barrel screw 218 are not shown in FIGS. 11 and 12. The barrel screw 218 engages the barrel extension 214 at the radial flange 220 and presses the radial flange 220 against the ledge 52 formed by the receiver 12.

[0145] The barrel screw 218 forms a gap 226 between itself and the barrel 94 and the barrel 94 extends through the barrel screw 218 without touching the barrel screw 218.

[0146] The barrel 94 has a rear portion 222 with a cylindrical outer shape and a male threading. The barrel extension 214 has a barrel hole 224 that is a through bore with a cylindrical shape matching the outer shape of the rear portion 222 of the barrel 94. The rear portion 222 of the barrel 94 is positioned in the barrel hole 224, and the barrel hole 224 has a female threading that cooperates with male threading of the rear portion 222 of the barrel 24, thereby fixing the barrel 94 relative to the barrel extension 214.

[0147] As mentioned above, the receiver 12 has a gas-conduit bore 60 at its front end 18. The automatic rifle 10 is gas operated, and it has a gas-conduit 228 that can lead gases from the barrel 94 into the key way 70 via the gas-conduit bore 60. The receiver 12 further has a through-going hole 66 at its upper end 20. The barrel extension 214 has a bore 232 aligned with the hole 66, and a barrel extension pin 230 is inserted in both the bore 232 and the hole 66, thus rotationally fixing the barrel extension 214 relative to the receiver 12. The gas conduit 228 extends through the hole 66 in the receiver 22 and prevents the barrel extension pin 230 from leaving the hole 66.

[0148] The automatic rifle 10 has a forend 98 with through-holes 234 that match the forward facing screw holes 92 in the forward extension 48. The forend 98 is attached to the receiver 22 by way of screws (not shown) entering the holes 92 and 234 and engaging the receiver 12.

ITEM LIST

[0149] 10 automatic rifle [0150] 12 unitary receiver [0151] 14 bolt way [0152] 16 rear end of receiver [0153] 18 front end of receiver [0154] 20 upper end of receiver [0155] 22 lower end of receiver [0156] 24 right side of receiver [0157] 26 left side of receiver [0158] 28 rear opening of receiver [0159] 30 extension hole of receiver [0160] 32 ejection port [0161] 34 magazine well [0162] 36 well opening [0163] 38 holes for magazine catch [0164] 40 trigger housing seat [0165] 42 seat opening [0166] 46 bore axis [0167] 48 forward extension [0168] 50 screw hole [0169] 52 ledge between screw hole and extension hole [0170] 54 blind bore for safety detent spring [0171] 56 cut-out for a detent lever [0172] 58 holes for safety lever [0173] 60 gas-conduit bore [0174] 62 first pin hole [0175] 64 second pin hole [0176] 66 hole for barrel extension pin [0177] 70 key way [0178] 72 cut out for end of charging handle [0179] 74 pivot recess [0180] 76 first receiver flange [0181] 78 second receiver flange [0182] 80 third receiver flange [0183] 82 accessory rail [0184] 84 pivot-pin holes for grip assembly [0185] 86 lock-pin holes for grip assembly [0186] 88 beam [0187] 90 concave front edge of beam [0188] 92 screw holes for forend [0189] 94 barrel [0190] 96 front end of barrel [0191] 98 forend [0192] 100 buttstock assembly [0193] 102 grip assembly [0194] 104 barrel assembly. [0195] 106 trigger mechanism [0196] 108 safety mechanism [0197] 110 bolt assembly. [0198] 112 bolt [0199] 114 bolt carrier [0200] 116 firing pin channel [0201] 118 carrier key [0202] 120 charging handle [0203] 122 buffer [0204] 124 action spring [0205] 126 buffer tube [0206] 128 buttstock adapter [0207] 130 buttstock [0208] 132 bolt carrier opening [0209] 134 adaptor body [0210] 136 buffer retainer [0211] 138 first locking pin [0212] 140 first locking pin hole [0213] 142 first through bore in adaptor body [0214] 144 first extension pin [0215] 146 first adaptor flange [0216] 148 second adaptor flange [0217] 150 pivot shaft [0218] 152 pivot flange [0219] 154 second locking pin [0220] 156 second through bore in adaptor body [0221] 158 second extension pin [0222] 160 retainer washer [0223] 162 retainer pin [0224] 164 retainer pin hole [0225] 166 rotation locker [0226] 168 trigger [0227] 170 hammer [0228] 172 disconnector [0229] 174 housing [0230] 176 pin assembly [0231] 178 inner trigger pin [0232] 180 inner hammer pin [0233] 182 rigid beam [0234] 184 grip base [0235] 186 pistol grip [0236] 188 pivot pin of second pivot [0237] 190 lock pin [0238] 192 lock pin hole [0239] 194 trigger slit [0240] 196 upward extending portion [0241] 198 pivot pin of first pivot [0242] 200 safety lever [0243] 202 safety biasing mechanism [0244] 204 safety detent [0245] 206 safety-detent spring [0246] 208 detent lever [0247] 210 first recess [0248] 212 second recess [0249] 214 barrel extension [0250] 218 barrel screw [0251] 220 radial flange [0252] 222 rear portion of the barrel [0253] 224 barrel hole [0254] 226 gap [0255] 228 gas conduit [0256] 230 barrel extension pin [0257] 232 bore in barrel extension [0258] 234 through-holes