WO2018058174A1

WO2018058174A1 - A bolt action receiver assembly for a semiautomatic lower receiver

Info

Publication number: WO2018058174A1
Application number: PCT/AU2017/050988
Authority: WO
Inventors: Jeffrey Bacon
Original assignee: Oceania Precision Pty Ltd
Current assignee: Oceania Precision Pty Ltd
Priority date: 2016-09-30
Filing date: 2017-09-11
Publication date: 2018-04-05
Anticipated expiration: 2019-03-30
Also published as: AU2017334260A1; AU2017334260B2

Abstract

There is provided a bolt action receiver assembly for a semiautomatic lower receiver which may be used to convert a semiautomatic rifle to a bolt-action rifle by replacement of the upper receiver assembly, while retaining the remainder componentry of the semiautomatic rifle. The upper receiver has a magazine entrance corresponding to a magazine slot of the lower receiver; and a hammer entrance slot for a hammer of a trigger assembly of the semiautomatic lower receiver; and a bolt carrier engaging a co-axial firing pin. The bolt carrier reciprocates within the upper receiver under action of a handle. The handle guided within an upper receiver guide slot to rotate the bolt carrier with respect to the upper receiver between forward in-battery and forward out-of-battery positions and to slide lengthwise with respect to the upper receiver between the forward out-of-battery position and a rearward position. The bolt carrier comprises a hammer depressing protrusion which depresses the hammer when in the rearward position and a lengthwise hammer firing clearance slot coinciding with the hammer entrance slot when the bolt carrier is the forward in-battery position to allow clearance for the hammer to strike a rear end of the firing pin to detonate a round.

Description

A bolt action receiver assembly for a semiautomatic lower receiver

Field of the Invention

[1] This invention relates generally to a bolt action receiver assembly for a semiautomatic lower receiver. The present invention may be used to easily convert a semiautomatic rifle to a bolt-action rifle by replacement of the upper receiver assembly, while retaining the remainder componentry of the semiautomatic rifle.

[2] The present invention has been developed primarily for use with of any A -15 & AR-10 (AR308) type rifle but may be applicable for use with other suitable semiautomatic rifles also.

Summary of the Disclosure

[3] There is provided herein a bolt action upper receiver assembly for a semiautomatic lower receiver.

[4] The bolt action assembly comprises an upper receiver having a magazine entrance corresponding to a magazine slot of the lower receiver and a hammer entrance slot for a hammer of a trigger assembly of the semiautomatic lower receiver.

[5] The bolt action assembly further comprises a bolt carrier engaging a co-axial firing pin.

[6] The bolt carrier reciprocates within the upper receiver under action of a handle. The handle is guided within an upper receiver guide slot to rotate the bolt carrier with respect to the upper receiver between forward in-battery and forward out-of-battery positions and to slide lengthwise with respect to the upper receiver between the forward out-of-battery position and a rearward position.

[7] The bolt carrier comprises a hammer depressing protrusion which depresses the hammer when in the rearward position. Furthermore, the bolt carrier comprises a lengthwise hammer firing clearance slot coinciding with the hammer entrance slot when the bolt carrier is the forward in-battery position.

[8] As such, the lengthwise hammer firing clearance slot allows clearance for the hammer to strike a rear end of the firing pin to detonate a round when in the forward in-battery position.

[9] US 2011/0168009 Al (ROBB et al.) 14 July 2011 [hereinafter referred to as Dl] discloses a bolt assembly for a rifle configured for recoil blowback operation and cooperation with a round of ammunition dispensed from a magazine into a firing chamber of the rifle. An extractor disposed in a lower, forward portion of the bolt assembly and an ejector disposed in an upper, forward portion of the bolt assembly further cooperate with the round of ammunition to extract a spent cartridge of the round of ammunition from the firing chamber and eject the spent cartridge downward from the firing chamber. [10] US 2010/0257768 Al (BARRETT) 14 October 2010 [hereinafter referred to as D2] discloses bolt action rifle having a safety latching mechanism which has an upper receiver including a movable bolt assembly, a lower receiver having a trigger assembly and releasably attached to the upper receiver, the bolt assembly movable between a cocked position and an uncocked position, and the upper receiver and the lower receiver including a latching mechanism operable to prevent the lower receiver from being detached from the upper receiver while the bolt assembly is in the cocked position.

[11] None of the prior art discloses a bolt carrier wherein the bolt carrier is configured for rotation between in-battery and out-of-battery positions with respect to the upper receiver and comprising a hammer firing clearance slot along the length of the bolt carrier to allow the hammer to strike a rear end of the firing pin to detonate a round in a forward in-battery position.

[12] In embodiments, the present assembly may comprise firing pin restrictor safety enhancement to prevent inadvertent discharge when out of battery.

[13] The hammer depressing protrusion may be configured for depressing the hammer until the hammer may be engaged by a sear of the trigger assembly.

[14] The hammer depressing protrusion may pass between feed lips of the magazine when the bolt carrier transitions between the forward out-of-battery and rearward positions.

[15] The bolt carrier may comprise a hammer inhibition protrusion in line with the hammer depressing protrusion which inhibits the hammer contacting the firing pin when the bolt carrier may be in the forward out-of-battery position.

[16] The bolt action upper receiver assembly may further comprise a firing pin restrictor comprising a catch, which, when the bolt carrier may be in the forward out-of-battery position, the firing pin restrictor may be pressed in by the upper receiver such that the catch catches the firing pin to prevent the firing pin from moving forwardly with respect to the bolt carrier.

[17] An interior of the upper receiver may comprise a clearance indentation which, when the bolt carrier may be in the forward in-of-battery position, allows the catch to move away from the firing pin to disengage the firing pin.

[18] The catch may catch and annulus of the firing pin.

[19] The firing pin restrictor may pivot about a pivot within a firing pin restrictor slot.

[20] An edge of the clearance indentation may transition gradually to assist depressing of the firing pin restrictor when the bolt carrier rotates from the forward in-battery to out-of-battery positions.

[21] The bolt action upper receiver assembly may further comprise a bolt connected to the bolt carrier.

[22] The bolt may comprise barrel engagement teeth. [23] The bolt carrier may rotate through 67.5° between the forward out of battery and in battery positions.

[24] The upper receiver may comprise a detent acting on the bolt carrier to bias the bolt carrier in either the forward in-battery position or the forward out-of-battery and rearward positions.

[25] The bolt carrier may comprise an in-battery seat and an out-of-battery slot for selectively engaging the detent.

[26] The bolt carrier may comprise magazine facing surfaces which face the magazine orthogonally when in the forward-in-battery position and the forward out-of-battery position respectively.

[27] The magazine facing surfaces are offset by 67.5°.

[28] The upper receiver may comprise a spent cartridges ejection slot through which spent cartridges are ejected when the bolt carrier rotates from the forward in-battery position to the forward out-of-battery position.

[29] Other aspects of the invention are also disclosed. Brief Description of the Drawings

[30] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[31] Figure 1 shows a disassembled view of a bolt action upper receiver assembly for a semiautomatic lower receiver in accordance with an embodiment;

[32] Figures 2 - 6 show a bolt in accordance with an embodiment;

[33] Figures 7 - 12 show a bolt carrier in accordance with an embodiment;

[34] Figures 13 - 17 show an upper receiver in accordance with an embodiment;

[35] Figure 18 and 19 so the upper receiver engaged by the lower receiver;

[36] Figure 20 - 21 show a lower semiautomatic rifle receiver;

[37] Figure 22 shows a firing pin; and

[38] Figure 23 shows a firing pin restrictor in accordance with an embodiment. Description of Embodiments

[39] Figure 1 shows a bolt action upper receiver assembly 1 for a semiautomatic lower receiver 3.

[40] The conversion 1 comprises an upper receiver 2 and a bolt carrier 4 reciprocating therein.

[41] The bolt carrier 4 carries a bolt 7. The bolt 7 may be selectively fastened to the bolt carrier 4 utilising orthogonal barrel pin 9. The bolt 7 as is substantially shown in figure 2 may be standard and comprise a cartridge extractor pocket 15 except that the rear of bolt 7 may be machined to engage the bolt carrier 4, including removal of the gas rings of conventional semiautomatic bolts, such as A 15/10 bolts.

[42] The upper receiver 2 connects to the semi-automatic lower receiver 3 utilising throughhole pin connection lugs 12.

[43] The upper receiver 2 defines a magazine entrance 27 corresponding to the magazine slot 30 of the lower receiver 3. The upper receiver 2 further comprises a hammer entrance slot 28 through which a hammer (not shown) of a trigger assembly of the lower receiver 3 acts.

[44] The conversion 1 comprises a firing pin 6 coaxially and slidably retained through the bolt carrier 4 and a bore 16 of the bolt 7. The hammer of the semi-automatic lower receiver 3 is able to strike the rear of the firing pin 6 through the hammer entrance slot 28 such that the tip of the firing pin 6 protrudes through the bolt 7 to detonate the round. The firing pin 6 may be biased rearwardly by bias compression spring 8 acting between the bolt 7 and the firing pin 6.

[45] The bolt carrier 4 is positionable within the upper receiver 2 under action of handle 5.

[46] The handle 5 is guided by an upper receiver slot (as is best shown in figure 17) so as to rotate the bolt carrier 4 between a forward in-battery position 32 and a forward out-of-battery position 35 and to slide lengthwise to a rearward position 31.

[47] Spent cartridges escape via ejection slot 34 when the bolt carrier 4 rotates from the forward in-battery position 32 to the forward out-of-battery position 35. The bolt carrier 4 may comprise magazine facing surfaces 38, 36 which face the magazine orthogonally when in the forward-in-battery position 32 and the forward out-of-battery position 35 respectively.

[48] A detent 33 may alternately engage an in-battery-position seat 26 and an out-of-battery channel 37 (as is best shown in figure 7) to biases the bolt carrier 4 in in-battery or out-of-battery positions.

[49] The bolt carrier 4 may comprise a forward cartridge extractor clearance 39 allowing the functioning of the cartridge extractor once the bolt 7 is pinned into the bolt carrier 4.

[50] A fire pin restrictor 11 may selectively interfere with the firing pin 6 to prevent inadvertent discharge when out-of-battery.

[51] Utilisation of the conversion 1 comprises removal of the upper receiver of a semiautomatic rifle.

[52] The upper receiver 2 is then connected to the lower receiver 3 of the semiautomatic rifle via throughhole pin connection lugs 12.

[53] A magazine is then loaded through the lower receiver magazine slot 30 such that the feed lips thereof reach through the upper receiver magazine entrance 27. [54] For loading, the handle 5 is pulled rearwardly to configure the carrier 4 in the rearward position.

[55] As the bolt 7 travels behind the magazine feed lips, a round is allowed to be pushed up in front of the bolt 7. A biasing spring (not shown) may reside within the stock to bias the bolt carrier 4 forwardly. Buffer spring pin clearance 17 may make allowance for a buffer spring engagement pin (not shown). Specifically, spring pin clearance 17 is cut in so that the bolt carrier 4 can be rotated 67.5 deg without contacting the buffer spring retention pin. This pin travels unobstructed in out-of-battery raceway 37 when the carrier/bolt is in out-of-battery rotation and pulled to the rearward position in the upper receiver.

[56] As is shown in figure 10, when the bolt carrier 4 transitions rearwardly a hammer depressing protrusion 20 pushes the hammer 2 downwardly so to reset the hammer.

[57] In a preferred embodiment, the hammer depressing protrusion 20 depresses the hammer sufficiently so as to be engaged by the sear of the trigger assembly so as to be operably disconnected until released.

[58] The hammer depressing protrusion 20 may pass between the feed lips of the magazine and therefore may be suitably narrow to fit between the feed lips.

[59] The handle 5 is then pushed forwardly to the forward out-of-battery position 35.

[60] As such, the bolt 7 pushes the engaged round forwards to the barrel, ready for firing.

[61] As the hammer depressing protrusion 20 leaves the hammer, the hammer may be left operably disconnected by the sear.

[62] When in the forward out-of-battery position 35, a hammer inhibition protrusion 18 may prevent the hammer from striking the firing pin 6.

[63] Additionally, the hammer inhibition protrusion 18 may keep the hammer down far enough past the sear such that that if the trigger is pulled in this out-of-battery rotation the trigger disconnect is tripped. As such, if the carrier 4 if then the out-of-battery position to the in-battery position whilst the trigger is held pulled, the hammer will not fall and strike the fire pin 6 as the disconnect has engaged the hammer. The interface 42 between the hammer inhibition protrusion 18 and the hammer clearance slot 19 keeps the hammer depressed past the disconnect when being rotated.

[64] As such, only when the trigger is released will the hammer now engage the sear requiring the trigger to be be pulled again to discharge the firearm.

[65] Such addresses problems of traditional bolt action designs, where it is possible to de-cock the firearm by pulling the trigger in the out-of-battery forward rotation and holding the trigger in while rotating to the in-battery rotation. This may cause the fire pin to hit the cartridge and, although not under full pressure, may dangerously cause accidental discharge. [66] The fire pin restrictor 11 may be utilised as an additional safety mechanism in embodiments.

[67] As is best shown in figure 10, firing pin restrictor 11 may comprise a catch 21. When the bolt carrier 4 is in the forward out-of-battery position 35, the fire pin restrictor 11 may be depressed by the upper receiver such that the catch 21 catches the firing pin 6 to prevent the firing pin from moving forwardly.

[68] As shown, the firing pin restrictor 11 may pivot about a pivot point 23 within a firing pin restrictor entrance slot 22. The firing pin restrictor 11 may be biased outwardly via a biasing spring engaged within biasing spring seat 24.

[69] The catch 21 may catch an annulus 29 (as is shown in figure 22) of the firing pin 6.

[70] An interior of the upper receiver 2 may comprise a clearance indentation 25 (as is shown in figure 16) which, when the bolt carrier 4 is in the forward out-of-battery position 35, allows the catch

21 to move away from the firing pin 6 to allow the firing pin 6 to move forwardly.

[71] When the bolt carrier 4 rotates to the out-of-battery position 35, the clearance indentation

25 may push the restrictor 11 inward to again interfere with the annulus 29 of the firing pin 6. Should the firing pin 6 have seized, the annulus 29 of the firing pin 6 prevents the restrictor 11 from moving inwardly and thereby prevents the bolt carrier 4 from moving to the out-of-battery position 35, requiring servicing.

[72] An edge of the clearance indentation 35 may transition gradually to assist in depressing the firing pin restrictor 11 when the bolt carrier 4 moves from the forward in-battery 35 to out-of-battery 35 positions.

[73] The bolt carrier may comprise a drilling 40 as is shown in figure 12 to retain a fire pin retention pin (not shown). This pin sets the reward position of the fire pin 6, and stops the fire pin 6 from extending rearwardly from the bolt carrier, especially as the fire pin 6 is under spring pressure of the biasing spring 8. elatedly, the catch 21 serves two purposes as alluded to above, firstly stopping the fire pin 6 from hitting the cartridge when in out-of-battery rotation and preventing fouling on the fire pin 6 if the fire pin 6 where to seize in the forward fired position by not letting the carrier 4/bolt 7 be rotated into the out-of-battery rotation, as the fire pin restriction device 11 cannot be pressed in on account of being obstructed by the pin 6.

[74] The handle 5 is then moved down to rotate the bolt carrier 4 to the forward in-battery position 32.

[75] As the bolt carrier 4 rotates, the locking teeth 14 of the bolt 7 engage the barrel. In this manner, the battery slot 32 may allow the bolt carrier 4 to rotate by 67.5° so as to allow for the engagement and disengagement of the teeth 14 accordingly. [76] As the bolt carrier 4 rotates, hammer inhibition ramp 18 rotates away such that hammer firing clearance slot 19 coincides with the hammer entrance slot 28 of the upper receiver 2.

[77] As such, the trigger may be released to disengage the sear and then pulled so as to cause the hammer to strike through the hammer firing clearance slot 19 to strike the rear of the firing pin 6 to detonate the round.

[78] Angular cut 42 may allow the bolt carrier 4 to rotate from out-of-battery to in-battery when the last round is stripped from the magazine. Specifically, when the last round is stripped from the magazine, the magazine follower contacts the bolt hold open catch. The bolt hold open catch is part of the lower receiver and between the rear of the magazine and the front of the hammer. Without this angular cut 42, the carrier cannot depress the bolt catch without fouling and restricting the rotation of the bolt carrier on the last shot.

[79] Furthermore angular cut 43 allows the bolt carrier 4 to clear the front portion of the bullet that protrudes past the feed lips of the magazine while being rotated from out-of-battery to in-battery rotation.

[80] As is shown in Figure 12, the bolt carrier 4 may comprise a ramp 41 to move the hammer rearward after the trigger has been pulled and the hammer has contacted the rear of the fire pin 6 as the carrier 4/bolt 7 is rotated from in battery to out of battery rotation. The ramp 41 moving the hammer 2mm rearward in the rotation, takes pressure off the fire pin 6, and the fire pin 6 moves back under spring pressure of the biasing spring 8 to clear the catch 21 of the fire pin obstruction device 11.

[81] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, they thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

Claims

1. A bolt action upper receiver assembly for a semiautomatic lower receiver, the bolt action assembly comprising:

an upper receiver having:

a magazine entrance corresponding to a magazine slot of the lower receiver; and a hammer entrance slot for a hammer of a trigger assembly of the semiautomatic lower receiver; and

a bolt carrier engaging a co-axial firing pin, the bolt carrier reciprocating within the upper receiver under action of a handle, the handle guided within an upper receiver guide slot to rotate the bolt carrier with respect to the upper receiver between forward in-battery and forward out-of- battery positions and to slide lengthwise with respect to the upper receiver between the forward out-of-battery position and a rearward position, wherein,

the bolt carrier comprises:

a hammer depressing protrusion which depresses the hammer when in the bolt carrier is in the rearward position; and

a lengthwise hammer firing clearance slot coinciding with the hammer entrance slot when the bolt carrier is the forward in-battery position to allow clearance for the hammer to strike a rear end of the firing pin to detonate a round.

2. A bolt action upper receiver assembly as claimed in claim 1, wherein the hammer depressing protrusion is configured for depressing the hammer until the hammer is engaged by a sear of the trigger assembly.

3. A bolt action upper receiver assembly as claimed in claim 1, wherein the hammer depressing protrusion passes between feed lips of the magazine when the bolt carrier transitions between the forward out-of-battery and rearward positions.

4. A bolt action upper receiver assembly as claimed in claim 1, wherein the bolt carrier comprises a hammer inhibition protrusion in line with the hammer depressing protrusion which inhibits the hammer contacting the firing pin when the bolt carrier is in the forward out-of-battery position.

5. A bolt action upper receiver assembly as claimed in claim 1, further comprising a firing pin restrictor comprising a catch, which, when the bolt carrier is in the forward out-of-battery position, the firing pin restrictor is pressed in by the upper receiver such that the catch catches the firing pin to prevent the firing pin from moving forwardly with respect to the bolt carrier.

6. A bolt action upper receiver assembly as claimed in claim 5, wherein an interior of the upper receiver comprises a clearance indentation which, when the bolt carrier is in the forward in-of- battery position, allows the catch to move away from the firing pin to disengage the firing pin.

7. A bolt action upper receiver assembly as claimed in claim 5, wherein the catch catches and annulus of the firing pin.

8. A bolt action upper receiver assembly as claimed in claim 7, wherein the firing pin restrictor pivots about a pivot within a firing pin restrictor slot.

9. A bolt action upper receiver assembly as claimed in claim 6, wherein an edge of the clearance indentation transitions gradually to assist depressing of the firing pin restrictor when the bolt carrier rotates from the forward in-battery to out-of-battery positions.

10. A bolt action upper receiver assembly as claimed in claim 1, further comprising a bolt connected to the bolt carrier.

11. A bolt action upper receiver assembly as claimed in claim 10, wherein the bolt comprises barrel engagement teeth.

12. A bolt action upper receiver assembly as claimed in claim 11, wherein the bolt carrier rotates through 67.5° between the forward out of battery and in battery positions.

13. A bolt action upper receiver assembly as claimed in claim 1, wherein the upper receiver comprises a detent acting on the bolt carrier to bias the bolt carrier in either the forward in-battery position or the forward out-of-battery and rearward positions.

14. A bolt action upper receiver assembly as claimed in claim 13, wherein the bolt carrier comprises an in-battery seat and an out-of-battery slot for selectively engaging the detent.

15. A bolt action upper receiver assembly as claimed in claim 1, wherein the bolt carrier comprises magazine facing surfaces which face the magazine orthogonally when in the forward-in- battery position and the forward out-of-battery position respectively.

16. A bolt action upper receiver assembly as claimed in claim 15, wherein the magazine facing surfaces are offset by 67.5°.

17. A bolt action upper receiver assembly as claimed in claim 1, wherein the upper receiver comprises a spent cartridges ejection slot through which spent cartridges are ejected when the bolt carrier rotates from the forward in-battery position to the forward out-of-battery position.