Gun barrel

• US 4,527,348 A
• Filed: 01/27/1984
• Issued: 07/09/1985
• Est. Priority Date: 01/27/1984
• Status: Expired due to Term

• Current Assignee: Gerald B. Lucas
• Original Assignee: D C Brennan Firearms Incorporated
• Inventors: Brennan, Dean C.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): Parr, Ted L.
• Application Number:
  US06/574,658
• Time in Patent Office: 529 Days
• Field of Search: 42/78, 42/76 R, 42/79, 89/14 R
• US Class Current: 42/76.01
• CPC Class Codes: F41A 21/16 Barrels or gun tubes characterised by the shape of the bore
• CPC Class Codes: F41A 21/28 Gas-expansion chambers; Barrels provided with gas-relieving ports F41A1/06, F41A13/08 and F41A21/36 take precedence

Abstract

A gun barrel adapted to be connected to a receiver includes a rifled portion and a smoothbore portion. The rifled portion may have deeper than normal grooves to permit the escape of propellant gases past the bullet. The smoothbore portion includes an increased diameter expansion section, a reduced diameter compression section and an alignment section. Gases expanding past the bullet reduce the peak pressure in the gun barrel and provide a relatively low pressure adjacent the muzzle at the time of bullet exit. The improved gun barrel affords increased bullet velocity and accuracy, and reduced felt recoil.

Claims

1. A gun barrel for firing a bullet and adapted to be attached to a receiver comprising a cartridge chamber, a rifled section extending from the cartridge chamber for imparting rotation to the bullet, at least some of the riflings in the rifled section being deeper than in a conventional gun barrel to permit propellant gases to expand past the bullet in the rifled section, a smoothbore expansion section extending from the rifled section having a diameter greater than the bullet caliber to permit propellant gases to expand past the bullet and subject the bullet to a forward drag effect, the expanding gases also functioning to evacuate the atmosphere from the gun barrel ahead of the bullet, a smoothbore compression section of decreasing diameter extending from the expansion section to increase the gas flow velocity and thus further accelerate the bullet, and a smoothbore alignment section extending from the compression section and having a diameter less than the bullet caliber to align the bullet on a constant rotational axis to improve accuracy.

2. A gun barrel as defined in claim 1, in which a crown expansion section of increased diameter substantially greater than the bullet caliber extends from the alignment section to protect the exit of the alignment section and to control the gases to be released past the bullet.

3. A gun barrel for firing a bullet and adapted to be attached to a receiver comprising along its length a cartridge chamber, a rifled section, at least some of the riflings in the rifled section being deeper than in a conventional gun barrel to permit propellant gases to expand past the bullet in the rifled section, an expansion section of increased diameter, a compression section of decreasing diameter, the compression section final diameter being less than that of the expansion section, and an alignment section having a diameter less than the bullet caliber, the sections forward of the rifled section being smoothbore to lower bore friction and increase bullet velocity, and the sections being of such diameter that they cooperate to permit propellant gases to expand past the bullet and subject it to a forward drag effect, the expanding gases also functioning to evacuate the atmosphere from the gun barrel ahead of the bullet.

4. A gun barrel as defined in claim 3, in which a crown expansion section of increased diameter substantially greater than the bullet caliber extends from the alignment section to protect the exit of the alignment section and to control the gases to be released past the bullet.

5. A gun barrel for firing a bullet and adapted to be attached to a receiver comprising along its length a cartridge chamber, a rifled section, an expansion section of increased diameter, a compression section of decreasing diameter, the compression section final diameter being less than that of the expansion section, and an alignment section having a diameter less than bullet caliber to align the bullet on a constant rotational axis to improve accuracy, the sections forward of the rifled section being smoothbore to lower bore friction and provide increased bullet velocity, and the smoothbore sections being of such diameter that they cooperate to permit propellant gases to expand past the bullet and subject it to a forward drag effect, the expanding gases also functioning to evacuate the atmosphere from the gun barrel ahead of the bullet, the expansion of the gases past the bullet reducing peak pressure in the barrel and providing relatively low gas pressure adjacent the muzzle at the time of bullet exit compared to the gas pressure adjacent the muzzle in a conventional gun barrel at the time of bullet exit, the reduced peak pressure affording safer gun firing and the low muzzle gas pressure providing reduced bullet deformation and muzzle blast to improve accuracy and reduce felt recoil.

6. A gun barrel as defined in claim 5, in which a crown expansion section of increased diameter substantially greater than the bullet caliber extends from the alignment section to protect the exit of the alignment section and to control the gases to be released past the bullet.

7. A gun barrel as defined in claim 5, wherein at least some of the riflings in the rifled section are deeper than in a conventional gun barrel to permit propellant gases to expand past the bullet in the rifled section and lower peak pressure.

8. A method of providing decreased felt recoil and increased velocity when firing a bullet through a gun barrel comprising the steps of burning a propellant to provide expanding.gases to propel the bullet through a rifled section of the barrel, permitting propellant gases to expand past the bullet in the rifled section and a smoothbore section of the barrel to reduce peak gas pressure in the barrel thus affording safer gun firing, the amount of gases expanding past the bullet being sufficient to provide relatively low gas pressure adjacent the muzzle at the time of bullet exit compared to the gas pressure adjacent the muzzle in a conventional gun barrel, the low gas pressure reducing bullet deformation and muzzle blast, whereby bullet accuracy is increased and felt recoil is reduced.

9. A method of firing a bullet through a gun barrel comprising the steps of providing a gun barrel with a rifled section and smoothbore sections, burning a propellant to provide expanding gases at the entrance of the rifled section to propel a bullet through the section and impart rotation to the bullet, guiding the bullet to a smoothbore increased diameter expansion section to permit the gases to expand past the bullet and subject the bullet to a forward drag effect and evacuate the atmosphere from the gun barrel ahead of the bullet, guiding the bullet to a decreasing diameter smoothbore compression section to increase the gas flow velocity, and guiding the bullet to a smoothbore alignment section having a diameter less than the bullet caliber to align the bullet on a constant rotational axis to improve accuracy, the alignment section being of such diameter that it permits gases to continue to expand past the bullet, the foregoing steps providing relatively low gas pressure adjacent the muzzle at the time of bullet exit in comparison. with the gas pressure adjacent the muzzle in a conventional gun barrel at the time of bullet exit with resulting reduced bullet deformation and muzzle blast, whereby bullet accuracy is increased and felt recoil is reduced.

10. A method as defined in claim 9, wherein significant amounts of the propellant gases are permitted to expand past the bullet in the rifled section to reduce peak gas pressure in the barrel thus affording safer gun firing.