Abstract
A semi-automatic or automatic rifle comprising a barrel attached to and upper receiver and including a compressible bolt carrier extension system. The compressible bolt carrier extension system includes a bolt carrier, an extension spring, two pins, and a reciprocation bolt carrier extension piece. As a whole, the compressible bolt carrier extension system makes possible the use of elongated upper and lower receivers to be used for chambering long-action or other center fire cartridges for use with AR rifles such as the M-16, and M4 etc., eliminating the need for any buffer or buffer tubes other than those commercially available. A further advantage of the compressible bolt carrier extension system is the reduction of felt recoil as the system fully loads during the recoil stroke as it pushes against the buffer absorbing additional recoil energy. The system can be incorporated into firearms using a variety of cartridges.
Claims
1. A bolt carrier system for a firearm, comprising: a bolt carrier comprising a first stop surface; and a bolt carrier extension movably coupled with the bolt carrier and comprising a second stop surface, wherein the bolt carrier and the bolt carrier extension are arrangeable between an extended arrangement with the second stop surface spaced from the first stop surface and the bolt carrier and the bolt carrier extension defining a first total length, and a retracted arrangement with the first stop surface and the second stop surface engaged each other and the bolt carrier and the bolt carrier extension defining a second total length that is less than the first total length, and wherein the bolt carrier and the bolt carrier extension are resiliently biased into the extended arrangement.
2. The bolt carrier system of claim 1, wherein the bolt carrier extension is slidably received by the bolt carrier.
3. The bolt carrier system of claim 1, wherein at least a portion of the bolt carrier extension is slidably received within a channel of the bolt carrier.
4. The bolt carrier system of claim 1, wherein the bolt carrier and the bolt carrier extension are resiliently biased into the extended arrangement via at least one spring.
5. The bolt carrier system of claim 4, wherein the at least one spring is positioned between at least a portion of the bolt carrier and at least a portion of the bolt carrier extension.
6. The bolt carrier system of claim 4, wherein the at least one spring comprises a first end portion engaged with an aft portion of the bolt carrier and a second end portion engaged with a forward portion of the bolt carrier extension.
7. The bolt carrier system of claim 4, wherein the at least one spring is pre-loaded in tension.
8. The bolt carrier system of claim 1, wherein the bolt carrier comprises an assembly that includes a component that defines the first stop surface.
9. The bolt carrier system of claim 1, wherein the first stop surface comprises a first aft end surface of the bolt carrier.
10. The bolt carrier system of claim 1, wherein the first stop surface and the second stop surface face each other.
11. The bolt carrier system of claim 1, wherein the second stop surface is defined by a flange of the bolt carrier extension.
12. The bolt carrier system of claim 11, wherein the flange of the bolt carrier extension is positioned at an aft end portion of the bolt carrier extension.
13. The bolt carrier system of claim 1, wherein the bolt carrier extension is integral.
14. The bolt carrier system of claim 1, wherein an aft portion of the bolt carrier includes a first outermost surface in a radial direction, and wherein the second stop surface of the bolt carrier extension does not extend radially past the first outermost surface of the bolt carrier.
15. A firearm, comprising: a bolt carrier device, comprising: a bolt carrier comprising a first stop surface; and a bolt carrier extension movably coupled with the bolt carrier and comprising a second stop surface, wherein the bolt carrier and the bolt carrier extension are arrangeable between an extended arrangement with the second stop surface spaced from the first stop surface and the bolt carrier and the bolt carrier extension defining a first total length, and a retracted arrangement with the first stop surface and the second stop surface engaged each other and the bolt carrier and the bolt carrier extension defining a second total length that is less than the first total length, and wherein the bolt carrier and the bolt carrier extension are resiliently biased into the extended arrangement.
16. The firearm of claim 15, wherein the bolt carrier extension is positioned in the extended arrangement prior to firing of the firearm, and wherein an aft end of the bolt carrier extension is positioned adjacent a buffer assembly of the firearm.
17. The firearm of claim 15, wherein the bolt carrier extension is slidably received by the bolt carrier.
18. The firearm of claim 15, wherein the bolt carrier and the bolt carrier extension are resiliently biased into the extended arrangement via at least one spring.
19. The firearm of claim 15, wherein the bolt carrier comprises an assembly that includes a component that defines the first stop surface.
20. The firearm of claim 15, wherein the first stop surface comprises a first aft end surface of the bolt carrier.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross section view of an M16 family style rifle with the compressible bolt carrier extension system installed.
[0016] FIGS. 2A and 2B are perspective exploded views the preferred embodiment of the compressible bolt carrier extension system.
[0017] FIG. 3 is a perspective view of the current invention in its initially loaded state
[0018] FIG. 4 is a perspective view of the current invention in its fully loaded state of FIG. 3.
[0019] FIG. 5 is a cutaway view of the rifle showing the preferred embodiment in its fully loaded state of FIG. 4
[0020] FIG. 6 is a rear view of the bolt carrier extension piece.
[0021] FIG. 7 is a front perspective view of the carrier extension piece of FIG. 6.
[0022] FIG. 8 is a side view of the carrier extension piece of FIG. 7.
[0023] FIG. 9 is a top view of the carrier extension piece of FIG. 8.
[0024] FIG. 10 is a bottom perspective view of the bolt carrier.
[0025] FIG. 11 is an exploded perspective view of a prior art bolt carrier and weight.
[0026] FIG. 12 is an exploded perspective view of a prior art buffered bolt assembly.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0027] Turning now to the drawings, reference characters throughout the several drawings depict like elements. FIG. 1 illustrates a side view of a rifle generally designated 9. In which is illustrated the preferred embodiment 10 of the invention installed in an upper receiver 11 of the family of M16/AR style rifles 9 in a pre-loaded state. It should be understood by one skilled in the art that any of the family of M16 style rifles may incorporate one or more of the modifications described herein. It should also be understood that all the family of M16 rifles having the designation M proceeding the model number as well as the designation AR are included but not limited thereto. Now turning back to FIG. 1, the upper receiver 11 and lower receiver 12 are configured in the current invention to accommodate the chambering of other center fire or long-action cartridges for use in AR style rifles 9. To accomplish using a long action cartridge on an AR type rifle 9, the upper receiver 11, lower receiver 12, and magazine well 41, all may have to be enlarged proportionally so as to accommodate a longer bolt carrier 13. In order to proportionally enlarge elements 11, 12, and 13, for use with long-action cartridges, the weighted buffer assembly 14, buffer spring 15, buffer tube cylindrical cavity 40 and buffer tube 16 would also have to be modified proportionally to receive the longer bolt carrier 13, in a retracted position as shown in FIG. 5. This would require the use of proprietary and non-commercially available buffer tube 16, buffer spring 15, and weighted buffer assembly 14 to be developed creating additional costs in tooling, manufacturing, sales, and marketing all of which the preferred embodiment of current invention solves.
[0028] Turning now to FIGS. 2-9 with further reference to FIG. 1 the preferred embodiment 10 of the current invention will be fully described. FIG. 2A shows an exploded view of the preferred embodiment 10 of the invention specifically. The compressible bolt carrier extension system 10 consists of bolt carrier extension piece 19, having end flange 44, extension spring 17 having fore and aft spring looped ends 20, a fore pin 21 connecting the fore looped end 20 of extension spring 17 to two horizontal bolt carrier extension piece apertures 22 located in the forward end of bolt carrier extension piece branches 23. The aft pin 25 connects the aft looped end 20 of the extension spring 17 to the aft end of the bolt carrier 13 through bolt carrier branches 27 and bolt carrier extension piece length limiting and alignment slots 28. The exterior carrier extension piece cylindrical surface 38 slide ably fits within the bolt carrier cylindrical cavity 39. FIG. 2A is shown an elongated bolt carrier firing pin access slot 43 to allow removal of the firing pin 24 without disassembly of the compressible bolt carrier extension system 10. FIG. 2B shows the fore pin 21 installed through horizontal bolt carrier extension piece apertures 22 and forward looped end 20 of the extension spring 17. FIG. 2B also depicts the installation of aft pin 25 through horizontal bolt carrier apertures 26, bolt carrier extension piece length limiting and alignment slots 28, and aft looped extension spring end 20 of extension spring 17.
[0029] Referring now to FIG. 3 is shown a fully assembled compressible bolt carrier extension system 10 with the exterior bolt carrier extension piece cylindrical surface 38 inserted into the aft end of the bolt carrier cylindrical cavity 39 in its initially loaded state and being held in its correct alignment by aft pin 25 as it passes through bolt carrier branches 27 and bolt carrier extension piece length limiting and alignment slots 28. The bolt carrier extension piece length limiting and alignment slots 28 are of a predetermined length coming to a stop against the aft pin 25 which determines the overall desired length of the compressible bolt carrier extension system 10 in its initially loaded state.
[0030] Turning now to FIG. 4, is shown the compressible bolt carrier extension system 10 with compressible bolt carrier extension piece 19 in a fully loaded state wherein the bolt carrier extension piece 19 and end flange 44 is fully docked and in contact with the aft bolt carrier face 29. This position would be achieved during the firing cycle when the bolt carrier extension system 10 is in a fully retracted position within the buffer tube 16 as referenced in FIG. 1. It is also shown that the compressible bolt carrier extension piece clearance notches 34 allow docking of the compressible bolt carrier extension 19 within the bolt carrier 13 by clearing bolt carrier branches 27.
[0031] Referring now to FIG. 5 is shown the present invention with compressible bolt carrier extension piece 19 as part of the complete compressible bolt carrier extension system 10 in its fully loaded and compressed state within a commercially available buffer tube 16. During the firing cycle the compressible bolt carrier extension system 10 moves in a rearward direction causing both the buffer spring 15 and compressible bolt carrier extension piece 19 to compress fully within the buffer tube 16. During this compression cycle of buffer spring 15 and compressible bolt carrier extension piece 19 pushing against one another, additional energy is absorbed during the firing cycle reducing the effect of felt recoil on a shooter. It is to be understood that adjustments to the compressible bolt carrier extension system 10 as shown in FIGS. 2A and 2B can be made for the use of specific cartridges.
[0032] Turning now to FIGS. 6-7 with further references to FIG. 4-5 are shown specific elements of the compressible bolt carrier extension piece 19 in several views. FIG. 6 shows an aft end view of the compressible bolt carrier extension piece 19. Bolt carrier extension piece radius tabs 30 are dimensioned to fit inside buffer tube cylindrical cavity 40 of buffer tube 16 as shown in FIG. 5. Bolt carrier extension piece buffer retaining pin clearance grooves 31 located on the top and bottom of compressible bolt carrier extension piece 19 provide clearance for the compressible bolt carrier extension piece 19 to clear the buffer retaining pin 33 shown in FIG. 5 as the compressible bolt carrier extension system 10 moves to a retracted position and then to a closed position during the firing cycle. Bolt carrier extension piece clearance notches 34 provide clearance for docking in the aft end of the bolt carrier extension piece 19 within bolt carrier branches 27 to the aft end of bolt carrier 13. FIG. 7 shows forward pin 21 installed through fore looped end 20 of extension spring 17 in bolt carrier extension piece 19. Extension spring 17 is installed in bolt carrier extension piece cylindrical cavity 18, also shown in FIG. 5.
[0033] FIGS. 8-9 show side views of the compressible bolt carrier extension piece 19 with a clearly defined spherical radius surface 35 on the aft end of the compressible bolt carrier extension piece 19 providing for a low friction single tangency point of contact with the weighted buffer assembly 14 as also shown in FIG. 5 Also shown are compressible bolt carrier extension piece length limiting and alignment slots 28, compressible bolt carrier extension piece forward stop surface 32, bolt carrier extension piece cylindrical cavity 18, bolt carrier extension piece exterior cylindrical surface 38, horizontal bolt carrier extension piece apertures 22, and compressible bolt carrier extension branches 23. FIG. 9 is shown a top view of the compressible bolt carrier extension piece 19, compressible bolt carrier extension branches 23, and extension spring access cut out 36 allowing access for assembly of extension spring 17. FIG. 9 further shows the pre-loaded state of the preferred embodiment 19 with fore pin 21 and aft pin 25 installed loading extension spring 17.
[0034] FIG. 10 is shown the bolt carrier 13 and bolt carrier hammer slot 37 which allows clearance for the firing pin 24, as shown in FIG. 1, to be struck by the hammer and interfaces with an auto sear for fully automatic firing.
[0035] FIG. 11 is shown a prior art bolt carrier with a reciprocating mass that utilizes locating and alignment slots similar to the current invention. However, the prior art as seen in FIG. 11 is provided to slow down firing cycle and does not deal with elongated upper and lower receivers at all.
[0036] FIG. 12 is shown a prior art buffered bolt assembly which utilizes bolt extensions similar to the current invention but located on the front end of the bolt assembly rather than on the aft end as shown in the current invention. The buffered bolt assembly shown in prior art FIG. 12 seeks to transfer stress concentrations away from certain latches and cam pins. The current invention, although utilizing extension pieces, does not seek to transfer loads away from any cam pins or latches, but rather to extend the bolt carrier for use of long-action or other center fire cartridges.
