B.L.T. BOLT CARRIER
A bolt assembly is provided for a firearm. The bolt assembly comprises a block adapted to connect to a firearm frame and a bolt carrier adapted to reciprocate within the frame. The bolt assembly comprises a support element between the block and the bolt carrier. The support element is adapted to reciprocate within the frame with respect to the cap and with respect to the bolt carrier. The first and second spaced apart parallel rods are connected to the cap and extending from the cap. The bolt carrier defines a pair of spaced apart bores receiving the rods. A first spring is interposed between the block and the support element, a second spring is received on the first rod, and a third spring is received on the second rod.
This application claims the benefit of U.S. Provisional Patent Application No. 62/400,826 filed on Sep. 28, 2016, entitled “BLT Bolt Carrier” which is hereby incorporated by reference in its entirety for all that is taught and disclosed therein.
BACKGROUND OF THE INVENTIONNormal AR15 rifles have an extension tube that extends to the rear of the upper receiver and contains the recoil spring. Given the length of the bolt carrier, the recoil spring needs this length to compress and provide an adequate range of motion of the bolt carrier. A disadvantage of a standard AR recoil assembly, the travel of the buffer to the rear of the buffer tube causes the weapon to have more felt recoil due to more mass at the rear of the weapon. While fine for rifles with normal shoulder stocks, the protruding extension tube is a problem for pistol variants of the AR 15, as well as folding or fully collapsing stocks, which are incompatible with a fixed extension tube.
Accordingly, it is desirable to create a shorter bolt carrier that has a recoil spring capability that operates fully within the limited length of an AR-15 upper, with no extension tube. Due to spring resonance of a shorter operating platform, the BCG weight is operating closer to center axis, and less recoil is noticed as muzzle flip is reduced.
BRIEF DESCRIPTION OF THE DRAWINGSAn end cap 5 is threaded 11 to connect to the lower receiver (not shown) on existing threads where a stock might normally be attached, in line with the center of the barrel bore and bolt carrier. The cap essentially becomes the rear wall of the receiver, and the fixed frame of reference that the bolt reciprocates with respect to. A rear spring (coil, compression) 17 is captured between the center support 4 and the cap. Thus, as the bolt reciprocates, the main springs 16 and rear spring 17 both compress, each storing some of the recoil energy for recover for stripping and chambering the next round. The center support 4 floats between the bolt carrier and the cap during recoil cycling, at a middle position between the two.
If a single rear spring were used (as in a conventional AR-15), it would have to be much longer, and the “end cap” would need to be lengthened to become an extension tube. This is partly due to the need to absorb recoil energy, and partly due to the length of the fully collapsed spring when the coils are stacked against each other, a condition normally to be avoided. It is not possible to extend the rear spring forward into or around the bolt carrier because of the needed structure and functions of the bolt carrier. However, the main spring that resides in part within the bolt carrier bore provides this added spring capability without lengthening the rear spring undesirably. The three springs are essentially end to end, and the entire rear spring remains to the rear of the entire front spring in all conditions. These are serially connected with the center support gripped or pinched between them, and each spring has a size and shape based on the space it has to work within the B.L.T. BCG.
In this exploded view, the image shows the rear view of the main spring zero footprint pocket (6), the guide rods (2) that are attached to the center support (4). The end cap is the end of the B.L.T. BCG that houses the solid height of the rear spring.
The rear spring 17 presses on the rear surface of the flange of the center support 4, and the main springs press on the front surface of the flange, guided by the rods.
An end cap 5 is threaded 11 to connect to the lower receiver (not shown) on existing threads where a stock might normally be attached, in line with the center of the barrel bore and bolt carrier. The cap essentially becomes the rear wall of the receiver, and the fixed frame of reference that the bolt reciprocates with respect to. A rear spring (coil, compression) 17 is captured between the center support 4 and the cap. Thus, as the bolt reciprocates, the main spring 16 and rear spring 17 both compress, each storing some of the recoil energy for recovery for stripping and chambering the next round. The center support 4 floats between the bolt carrier and the cap during recoil cycling, at a middle position between the two.
If a single rear spring were used (as in a conventional AR-15) it would have to be much longer, and the “end cap” would need to be lengthened to become an extension tube. This is partly due to the need to absorb recoil energy, and partly due to the length of the fully collapsed spring when the coils are stacked against each other, a condition normally to be avoided. It is not possible to extend the rear spring forward into or around the bolt carrier because of the needed structure and functions of the bolt carrier. However, the main spring that resides in part within the bolt carrier bore provides this added spring capability without lengthening the rear spring undesirably. The two springs are essentially end to end, and entire rear spring remains to the rear of the entire front spring in all conditions. These are serially connected with the center support gripped or pinched between them, and each spring has a size and shape based on the space it has to work within.
In this extended position/installed length is a see through image that shows internal view of the main spring zero footprint pocket (6), the smooth guide rod (2) that is attached to the center support (4) by the threaded end (8), the retention guide rod (3) and the flared tip (7) that is inserted through the carrier from the front to the center support where it is threaded into the center support (4), now the carrier (1), main spring (16), guide rods and center support connected in operational order. The end cap is the end of the B.L.T. BCG that houses the solid height of the rear spring.
The rear spring 17 presses on the rear surface of the flange of the center support 4, and the main spring presses on the front surface of the flange, guided by the rod 2.
List of the parts:
1. B.L.T. (bufferless technology) Bolt Carrier
2. Guide Rod Smooth
3. Guide Rod Retention
4. Center support
5. End cap
6. Main spring “zero footprint” pocket
7. Flared end of retention guide rod
8. Threaded guide rod ends
9. Standard Cam cutout
10. Standard gas key cutout
11. End cap threads (standard buffer threads)
12. Standard dust cover cutout
13. Standard Gas stake bolt holes
14. Gas hole
15. Milspec B.C.G. bore hole
16. Main spring
17. Rear spring
Claims
1. A bolt assembly for a firearm comprising:
- a block adapted to connect to a firearm frame;
- a bolt carrier adapted to reciprocate within the frame;
- a support element between the block and the bolt carrier;
- the support element adapted to reciprocate within the frame with respect to the cap and with respect to the bolt carrier;
- first and second spaced apart parallel rods connected to the cap and extending from the cap;
- the bolt carrier defining a pair of spaced apart bores receiving the rods;
- a first spring interposed between the block and the support element;
- a second spring received on the first rod; and
- a third spring received on the second rod.
Type: Application
Filed: Sep 28, 2017
Publication Date: Aug 9, 2018
Inventor: Claude A. Durham, III (Lakeside, CA)
Application Number: 15/718,081