Patent Application
20150362303
The present disclosure relates to BULLET.
This section provides background information related to the present disclosure which is not necessarily prior art.
This invention relates to bullets, and in particular to a hollow point bullets.
Hollow point bullets have a cavity at the front of the bullet which facilitates the expansion of the bullet after it impacts its target. However, a problem with at least some hollow point bullets is that with some materials, such as wall board, the bullets don't expand as intended, and thus the performance and penetration is unpredictable. For many users, including but not limited to law enforcement users, it is important that a bullet perform predictably and consistently, to avoid unintended consequence. In fact the FBI has developed a test protocol (as of 2014) that measures a bullet's performance in a variety of materials:
Test event 1—Bare Gelatin
Gelatin block 10 feet from muzzle
Test event 2—Heavy Clothing
Gelatin block covered with four layers of clothing 10 feet from muzzle.
Test event 3—Steel
Two pieces of 20 gauge cold rolled galvanized steel
Test event 4—Wallboard
Two square pieces each ½ inch thick gypsum wallboard set 3.5 inches apart. Gel block is covered in one layer of cotton t-shirt and one layer of cotton shirt.
Gel block is 18 inches behind the rear most piece of wall board with the block 10 feet from muzzle.
Test event 5—Plywood
One square piece of 23/32 sanded pine plywood
Test event 6—Auto Glass
One piece of A.S.I ¼ inch thick laminated safety glass measuring 15×18 inches.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
Embodiments of the present invention provide a hollow point, expanding bullet, with improved performance in certain types of materials, and therefore improved consistency in performance. Generally a preferred embodiment of a bullet in accordance with the present invention comprises a metal jacket, having a generally cylindrical aft section, a tapering forward section, and an open front. There is a soft, dense, metal core disposed in the metal jacket. The core has a cavity generally aligned with the open front of the jacket, with a plurality of blades extending forwardly into the cavity, each terminating in a front face spaced rearwardly of the forward edge of the metal jacket.
In this preferred embodiment there are preferably at least three blades, each oriented along radius of the cavity, and the blades are preferably equally angularly spaced. The front faces of the blades are preferably spaced between about 0 and about 0.125 inches from the forward most edge of the opening in the jacket. In the preferred embodiment the area of the front faces of the blades comprises between about 35% and about 55% of the cross-sectional area of the cavity (in the plane of the front faces of the blades).
The blades preferably have a height of between about 0.060 and about 0.200 inches, which is preferably between about 30% and about 100% of the distance between the bottom of the cavity and the forward-most edge of the opening in the jacket. The cavity preferably has a volume of at least 0.0015 in3, and the blades preferably comprise at least 20% of the volume. The blades can be formed integrally with the core, or can comprise a separate piece formed in, or inserted into, the cavity.
The jacket preferably comprises copper or a copper alloy, although it could be made of other suitable material. The core preferably comprises lead or a lead alloy, although though it could be made of another relative soft, relatively dense metal, particularly if it is desired that the bullet be lead free.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
A preferred embodiment of a bullet in accordance with the principles of this invention is indicated generally as 20 in the Figures. The bullet 20 comprises a metal jacket 22, having a generally cylindrical aft section 24, a tapering forward section 26, and an open front 28. The jacket can be made of copper or a copper alloy, or other suitable material.
A metal core 30, preferably of a relatively soft, dense material such as lead or a lead alloy, is disposed in the metal jacket 22. The core 30 having a cavity 40 generally aligned with the open front 28 of the jacket 22. A plurality of blades 42 are disposed in the cavity 40, each to terminating in a front face 44 that is spaced rearwardly of the forward edge of the metal jacket 22. Although preferably made of lead, the core 30 could be made of another suitable relatively soft, dense material, particularly if it is desired to make the bullet “lead free.”
There are preferably at least three blades 42, each oriented along radius of the cavity 40. The blades 40 are preferably equally angularly spaced (for example in the case of three blades, the spacing is 120°, and in the case of four blades the spacing is 90°). The front faces 44 of the blades 42 are preferably spaced between about 0 and about 0.125 inches from the forward most edge of the opening 28 in the jacket 22. Preferably, the area of the front faces 42 of the blades 42 comprise about 35% and about 55% of the cross-sectional area of the cavity 40 (measured in the plane of the front faces 44 of the blades 42).
The blades can have a height of between about 0.060 and about 0.200 inches, which is preferably between about 30% and about 100% of the distance between the bottom of the cavity 40 and the forward-most edge of the opening 28 in the jacket 22. In the preferred embodiment the cavity 40 has a volume of at least 0.0015 in3, and the blades 42 comprise at least 20% of the volume.
In the preferred embodiment that blades 42 are formed integrally of the core material, but alternatively the blades could be formed separately and inserted into the cavity 40. In this case the blades 42 could be made of the same material as the core 30, the jacket 22, or some other material such as a metal or even a polymeric or other suitable material.
Bullets 20 of the preferred embodiment can be formed by drawing a copper or copper alloy into a cup shape, as shown in
The bullet can further be subjected to a knurling operation to lock the jacket onto the core. A knurl 50 can improve weight retention when the bullet is fired through certain barriers such as autoglass.
In operation, the blades 42 significantly improve the performance and consistency of the bullet compared to a hollow point bullet without the blades. FBI Protocol data for a hollow point bullet without the blades is shown in Table 1, while data for a hollow point bullet with the blades is shown in Table 2. The composite score for the convention hollow point bullet is 345 out of 500, while the composite score for the bladed hollow point bullet is 390 out of 500. A 45 point (11.5%) improvement. Tables 3A and 3B show the velocities for the testing shown in Tables 1 and 2, respectively. Tables 4A and 4B summarize the results shown in Tables 1 and 2,
The blades provide an improvement in the FBI protocol score by increasing the projectile penetration without greatly sacrificing the overall expanded diameter. Deeper penetration increases the score by eliminating any shots that penetrate less than 12″ which the protocol penalizes. In addition, it reduces the penetration standard deviation by allowing the “soft” barrier (bare gelatin & heavy cloth) penetrations to be more similar to the “hard” barrier penetrations such as steel. This is exemplified in
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
