FIREARM BARREL AND METHOD OF IMPROVING PROJECTILE WEAPON ACCURACY, VELOCITY AND DURABILITY

Abstract

A firearm barrel, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end to and exiting a muzzle end. The plurality of lands each include a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel. The reduced width component defines an acute angle in relation to a longitudinal axis of the barrel adapted to cause a bullet being fired from the firearm to prevent blow-by gases to exit the barrel in advance of the bullet. A method of forming the firearm and barrel is also disclosed.

Claims

1. A method of improving accuracy of a firearm comprising the steps of: providing a firearm barrel having a longitudinal axis, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end and exiting a muzzle end; forming in each of the plurality of lands a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel, wherein the reduced width component defines an acute angle in relation to the longitudinal axis of the barrel; and preventing blow-by gasses from exiting the barrel in advance of the bullet via the reduced width component.

2. The method of improving accuracy of a firearm of claim 1 further comprising the step of defining a triangular-shaped area on a side of the lands that is opposite a direction of the twist angle.

3. The method of improving accuracy of a firearm of claim 1 further comprising the step of forming the reduced width component by removing material from the barrel on a side of the lands that is opposite a direction of the twist angle.

4. The method of improving accuracy of a firearm of claim 1 wherein the reduced width component of the lands provides a 5 to 1 groove to land ratio.

5. A method of reducing recoil of a firearm comprising the steps of: providing a firearm barrel having a longitudinal axis, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end and exiting a muzzle end; forming in each of the plurality of lands a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel, wherein the reduced width component defines an acute angle in relation to the longitudinal axis of the barrel; and preventing blow-by gasses from exiting the barrel in advance of the bullet via the reduced width component.

6. The method of reducing recoil of a firearm of claim 5 further comprising the step of defining a triangular-shaped area on a side of the lands that is opposite a direction of the twist angle.

7. The method of reducing recoil of a firearm of claim 5 further comprising the step of forming the reduced width component by removing material from the barrel on a side of the lands that is opposite a direction of the twist angle.

8. The method of reducing recoil of a firearm of claim 5 wherein the reduced width component of the lands provides a 5 to 1 groove to land ratio.

9. A method of increasing muzzle velocity of a firearm comprising the steps of: providing a firearm barrel having a longitudinal axis, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end and exiting a muzzle end; forming in each of the plurality of lands a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel, wherein the reduced width component defines an acute angle in relation to the longitudinal axis of the barrel; and preventing blow-by gasses from exiting the barrel in advance of the bullet via the reduced width component.

10. The method of increasing muzzle velocity of a firearm of claim 9 further comprising the step of defining a triangular-shaped area on a side of the lands that is opposite a direction of the twist angle.

11. The method of increasing muzzle velocity of a firearm of claim 9 further comprising the step of forming the reduced width component by removing material from the barrel on a side of the lands that is opposite a direction of the twist angle.

12. The method of increasing muzzle velocity of a firearm of claim 9 wherein the reduced width component of the lands provides a 5 to 1 groove to land ratio.

13. A method of reducing lateral barrel deflection of a firearm comprising the steps of: providing a firearm barrel having a longitudinal axis, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end and exiting a muzzle end; forming in each of the plurality of lands a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel, wherein the reduced width component defines an acute angle in relation to the longitudinal axis of the barrel; and preventing blow-by gasses from exiting the barrel in advance of the bullet via the reduced width component.

14. The method of reducing lateral barrel deflection of a firearm of claim 13 further comprising the step of defining a triangular-shaped area on a side of the lands that is opposite a direction of the twist angle.

15. The method of reducing lateral barrel deflection of a firearm of claim 13 further comprising the step of forming the reduced width component by removing material from the barrel on a side of the lands that is opposite a direction of the twist angle.

16. The method of reducing lateral barrel deflection of a firearm of claim 13 wherein the reduced width component of the lands provides a 5 to 1 groove to land ratio.

17. A method of reducing chamber pressure in a firearm and improving a bullet's access to a barrel of the firearm comprising the steps of: providing a firearm barrel having a longitudinal axis, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end and exiting a muzzle end; forming in each of the plurality of lands a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel, wherein the reduced width component defines an acute angle in relation to the longitudinal axis of the barrel; and preventing blow-by gasses from exiting the barrel in advance of the bullet via the reduced width component.

18. The method of reducing chamber pressure in a firearm and improving a bullet's access to a barrel of the firearm of claim 17 further comprising the step of defining a triangular-shaped area on a side of the lands that is opposite a direction of the twist angle.

19. The method of reducing chamber pressure in a firearm and improving a bullet's access to a barrel of the firearm of claim 17 further comprising the step of forming the reduced width component by removing material from the barrel on a side of the lands that is opposite a direction of the twist angle.

20. The method of reducing chamber pressure in a firearm and improving a bullet's access to a barrel of the firearm of claim 17 wherein the reduced width component of the lands provides a 5 to 1 groove to land ratio.

21. A method of reducing erosion and abrasion in a firearm comprising the steps of: providing a firearm barrel having a longitudinal axis, including rifling formed of an alternating, spirally-extending plurality of grooves and lands defining a twist angle adapted for imparting rotation to a bullet being impelled through the barrel from a chamber end and exiting a muzzle end; forming in each of the plurality of lands a reduced width component communicating with the chamber end of the barrel for a predetermined distance towards the muzzle end of the barrel, wherein the reduced width component defines an acute angle in relation to the longitudinal axis of the barrel; and preventing blow-by gasses from exiting the barrel in advance of the bullet via the reduced width component.

22. The method of reducing erosion and abrasion in a firearm of claim 21 further comprising the step of defining a triangular-shaped area on a side of the lands that is opposite a direction of the twist angle.

23. The method of reducing erosion and abrasion in a firearm of claim 21 further comprising the step of forming the reduced width component by removing material from the barrel on a side of the lands that is opposite a direction of the twist angle.

24. The method of reducing erosion and abrasion in a firearm of claim 21 wherein the reduced width component of the lands provides a 5 to 1 groove to land ratio.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The present invention is better understood when the following detailed description of the invention is read with reference to the accompanying drawings, in which:

[0046] FIG. 1 is a fragmentary plan view of the chamber end of a prior art firearm barrel;

[0047] FIG. 2A is a partial vertical-cross section of a 45 automatic pistol;

[0048] FIG. 2B is an enlarged view of the chamber and the adjacent segment of the barrel in accordance with a preferred embodiment of the invention;

[0049] FIG. 3 is a radial cross-section of a conventional 45 automatic pistol barrel 0.125 inch from the chamber end of the barrel;

[0050] FIG. 4 is a radial cross-section at the chamber end of a 45 automatic pistol barrel at a distance of 0.125 inch from the end of the chamber in accordance with a preferred embodiment of the invention; and

[0051] FIG. 5 is a fragmentary side view with parts broken away of an automatic pistol showing the portion of the pistol barrel, in cross-section, adapted to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION AND BEST MODE

[0052] Referring now to the drawings, a fragmentary view of the chamber end of a barrel of a 45 caliber semi-automatic pistol of conventional manufacture is illustrated in FIG. 1 and shown generally by means of a fragmentary plan view illustrating a conventional rifling land that along its entire length extends at an angle, for example, 5 degrees, in relation to the longitudinal axis of the barrel. As noted, bullet rotation does not begin immediately, but proceeds straight into the barrel with the results explained above with reference to conventional, prior art barrel rifling.

[0053] When a chambered cartridge is fired, the bullet moves in a straightforward direction with no rotation until the leading edge of the rifling land can exert enough force to start the bullet to rotate. Until the bullet can attain full rotational speed, the surface of the bullet is being displaced, which in turn leaves displaced areas, i.e., “voids”, between the displaced surface and the trailing edges of the rifling as shown in FIG. 1. These displaced areas are not closed until the bullet has traveled far enough into the barrel so that the material in the bullet displaced by the rifling is forced back to fully fill the void.

[0054] During the time before the void is fully filled by the bullet, a portion of the propelling gases escape through the unclosed void, which is evidenced by a puff of smoke, which exits the muzzle of the barrel ahead of the bullet. When the cartridge is fired, the leading edge of the bullet strikes the full width of the riflings, the explosive force driving it causes the base of bullet to expand in diameter. This causes more deformation of the bullet which must be forced back to the size of the barrel bore in order to pass through.

[0055] As bullet diameters are usually matched to the groove diameter of the barrel, the lands of the barrel must be impressed into the bullet. Because metal is not compressible, the bullet must again be deformed so that it will not burst the barrel. The only way for this to be accomplished is for the bullet to extrude lengthwise. The bullet is now being deformed in three dimensions, in the circumferential direction to fill the void, in the lengthwise direction to make room for the rifling land displacement, and in the diametrical direction to swage back the deformed base of the bullet. All of these forces have a negative effect on the integrity and concentricity of the bullet as it existed before firing, compromising accuracy and power.

[0056] In contrast, and in accordance with a preferred embodiment of the invention, a pistol is shown at reference numeral 10 in FIG. 2A. Pistol 10 is broadly formed of a receiver 12, slide 14, and barrel 17. The receiver 12 has a grip 16 and carries a trigger mechanism including a trigger 18 and hammer 20. A magazine 21 is positioned in a chamber in the grip 16 and holds cartridges to be fed one-by-one into the firing chamber 22 of the pistol 10.

[0057] The barrel 17 is slidable and tiltable relative to the slide 14 and is connected to the receiver 12 through a link pivotally connected to an integrally-formed link lug formed on the barrel 17 by a pin. The barrel 17 is also pivotally connected to the receiver 12 by another pin of a slide stop. Further details may be found by reference to applicant's issued U.S. Pat. No. 5,753,848.

[0058] Barrel 17 includes a cylindrical barrel portion 26 having a central bore 28 with rifling grooves 30 separated by raised lands 32. As manufactured, a Colt 45 caliber pistol is relatively inaccurate except at short range. For this reason, Colt 45 caliber pistols intended for competition use are typically “accurized” to increase the accuracy of the pistol.

[0059] “Accurization” of a Colt 45 semi-automatic pistol according to prior art techniques includes four basic procedures:

[0060] 1. properly fitting the slide of the piston to the frame of the pistol;

[0061] 2. properly fitting the barrel 17 in the slide;

[0062] 3. properly fitting the locking grooves of the barrel 17 onto the mating locking wall segments of the slide 14; and

[0063] 4. fitting the link lug for proper camming action against the pin of the slide stop.

[0064] These procedures are described in applicant's prior U.S. Pat. No. 5,753,848 as noted above. Further accurization can be affected by modifying the configuration of the grooves 30 and lands 32 in accordance with the techniques set out and claimed in this application. Specifically, in accordance with the invention, a significant change is made to the conventional form of rifling by removing material from the sides of the lands opposite to the direction of the angle of the rifling twist. This, according to the aforementioned measurements, shall be in a straight line parallel to the longitudinal axis of the barrel for a distance of 0.350 inch from the end of the chamber, where it will begin to curve toward the leading or driving side of the rifling land. This curve shall continue 0.200 inch gradually at first and then curve more and more as the bullet engages more force from the rifling and where the bullet will attain full rotational speed and meet the trailing edge of the rifling and blend to its full width and rate of twist. See FIG. 2A and FIG. 5. Note particularly that in accordance with the invention both the grooves 30 and the lands 32 are now asymmetric along the first 0.320 inch of the barrel length.

[0065] As best shown in FIG. 5, this is accomplished by eliminating a triangularly-shaped area “T” from the lands 32 adjacent the end of the lands 32 and grooves 30. This asymmetry is critical to the improved functioning of the barrel of the 45 caliber semi-automatic pistol described in this application and is a distinctive departure from the prior art. As previously noted, this principle is equally applicable to any rifled barrel used to launch a projectile, be it a bullet, sabot, shell or other projectile.

[0066] As shown in FIG. 3, the width of the lands of a conventional 45 caliber pistol barrel is 0.080 inch and the width of the grooves is 0.160 inch, resulting in a 2/1 groove/land ratio.

[0067] As shown in FIG. 4, when the material is removed from the trailing edge of the rifling as described above, the initial width of the rifling lands is 0.040 inch, cutting the first encounter of the bullet with the barrel by 50 percent. The grooves are 0.200 inch, resulting in a 5/1 groove/land ratio, substantially reducing the initial impact of the bullet in the barrel. As the bullet enters the rifling, the portion of the prior art rifling that scraped and left a void in the bullet will no longer be there. Instead, one side of the back edge of the rifling will be straight, parallel with the centerline axis of the barrel and no void will be formed on the bullet. An absolute minimum of combustion gases will escape past the bullet, allowing the gases to remain behind the bullet to propel the bullet at a higher velocity. With virtually no gas escaping past the bullet, erosion at the end of the chamber is minimized, no burned or unburned powder and ash can precede the bullet down the bore to abrade and score the barrels surface. The scraping and reforming of the bullets surface no longer happens. All surfaces of the bullet will maintain their lubrication and metal fouling of the bore will be minimized or nonexistent. The instantaneous contact of the rifling restricted bore will not be as violent. The width of the lands will allow easier entry into the bore, resulting in less expansion of the base of the bullet, hence easier reforming to groove size. With the straight line back of the lands the entry of the bullet into the bore will allow a longer moment for the extrusion in length to take place. All of the above have an effect on the concentricity and integrity of the bullet. All of these factors will enhance the accuracy of a fired round.

[0068] In addition, preventing blow-by reduces the abrasive effect of the gases on the interior of the weapon barrel that over time can damage the barrel throat and bore. In addition to enhancing accuracy and providing the other advantages discussed in this application, the substantial reduction in gas etching and abrasion of the barrel interior substantially increases the life of the barrel.

[0069] It has been determined that removing material from the lands 32 of the barrel 17 near the entrance point of the chamber 22 allows the bullet to prevent the escape of blow-by gases from the barrel in advance of the bullet. This improves accuracy, power and substantially lengthens the useful life of the barrel. The angle of the lands 32 is changed to have two components—a first component at the chamber end of the barrel that has an angle that is parallel with the longitudinal axis of the barrel, and a second component that transitions from the angle of the first component to the angle of the lands 32, resulting in the asymmetry described above.

[0070] As best shown in FIG. 5, the triangular material “T” barrel material is eliminated on the side of the lands 32 opposite the direction of the angle of the rifling and prevents or substantially reduces blow-by, lateral barrel deflection, recoil, increases muzzle velocity and provides increased barrel life. Each different loading of powder, the rifling, the different texture of the bullet and the type of firearm will change the design of the following edge of the rifling. According to the exemplary embodiment of this application, a 0.030 inch gap between the front of the chamber 22 and the beginning of the lands 32 provides an area where the bullet is centered before the bullet fully enters the barrel 17. This provides a more geometrically-cylindrical bullet resulting in greater accuracy and less wear on the barrel 17, particularly the lands 32.

[0071] One embodiment of the invention is explained by way of example by reference in FIGS. 2A and 2B to a Colt 45 semi-automatic pistol with a 5 inch barrel. The barrel 17 rifling preferably has six 5 degree lands 32 having a left or right hand twist of one turn in 16 inches. The first component at the barrel 17 entrance at the transition point adjacent the chamber 22 is 0.350 inches long and, as noted above, is parallel to the longitudinal axis of the barrel 17. The second component defines a transition between the first component and the lands 30 in their conventional progression along the length of the barrel 17 to the muzzle end. The transition according to this embodiment of the invention is 0.200 inches long, the total length of the first and second components thus being 0.550 inches. The second component is curved, preferably progressively curved in the manner of a French curve to intersect and merge into the conventional spiral of the grooves 30 and lands 32 that extend the remainder of the length of the barrel 17 to the muzzle.

[0072] Therefore, the bullet initially engages narrower rifling lands 32 causing less initial impact, thus reducing recoil as well as bullet base expansion. The bullet more rapidly fully seals the lands 32 and the grooves 30 of the bore 28 at all times, thereby reducing or eliminating blow- by of propellant gases. Instead, the full force of the gases is exerted against the rear of the bullet resulting in an increase in bullet velocity.

[0073] The surface of the bullet where material in conventional barrels is displaced is “raw” and unlubricated. As this material is forced back into contact with the land 32 and groove 30 surfaces, these surfaces are prone to metal fouling and consequent loss of accuracy. In contrast, the barrel arrangement according to the present invention causes the lands 32 to be impressed into the bullet over a longer moment, allowing the bullet to elongate more gradually and consistently, thus minimizing eccentric deformation and maintaining the desired concentricity of the bullet.

[0074] Also, by not allowing superheated propellant gases and abrasive powder ash to escape past the bullet, the bore 28 of the barrel 26 will remain cleaner and unabraded longer. Gas etching and abrasion of the barrel and barrel throat is minimized, further extending barrel life. Less deformation and reformation of the bullet in diameter and length will amount to a major reduction in chamber pressure and thus provide a safer firearm.

[0075] While the normal barrel muzzle velocity of a 45 caliber bullet is approximately 750-790 feet/second, it is anticipated that the barrel exit speed of a 45 caliber bullet fired through the barrel 28 according to the invention of this application will be approximately 825-850 feet/second—a significant improvement in performance without any modification to the cartridge being fired. While the invention has been disclosed and explained with reference to a 45 caliber semiautomatic pistol, the invention has application to any weapon from which a bullet or similar projectile is fired through a rifled barrel, including revolver-type pistols, manual-load, semiautomatic and automatic rifles, both magazine and belt-fed and artillery.

[0076] While a firearm and weapon barrel according to the invention have been described with reference to specific embodiments and examples, it is envisioned that various details of the invention may be changed without departing from the scope of the invention. Furthermore, the foregoing description of the preferred embodiments of the invention and best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation.