This disclosure relates to guns that propel projectiles using compressed gas as a propellant. More particularly, it relates to an improved gun barrel for use in combination with a gas powered projectile gun firing soft or pliable ammunition such as paint balls or pepper balls. Paint balls have a liquid center covered by a thin plastic or gelatin membrane that maintains the paint ball in an approximately spherical shape. Pepper balls have a powder filled center covered by a thin hard plastic shell that is nevertheless flexible. Both types are called “soft projectiles” in this application. This application incorporates by reference the disclosure of U.S. Patent Publication No. 2005/0247295, titled “Barrel and ball sizer for paint-ball gun,” published Nov. 10, 2005.
With large-caliber, high-velocity guns there is some risk of the shock of impact with the rifling “stripping” the driving band of the shell. To combat this, some weapons have progressive rifling, in which the rifling grooves start out parallel then gradually increase in twist down the barrel. In barrels for soft-projectile guns, the relationship between the mass and size of the projectile and the propellant force is similar to that in conventional high-velocity cannon.
The gun barrel disclosed here preferably has progressive rifling to cause the rotation of the liquid or powder center of the ball to match the rotation of the outer membrane as the ball leaves the gun barrel. This results in enhanced ball stabilization against tumbling and drift in flight, leading to longer flights and improved accuracy. In other embodiments using the same methods for making, however, the rifling could be non-progressive.
The following table shows an exemplary degree of progressive rotational rifling from the breech of the bore of the barrel (100); here, causing no more than one rotation in 42 inches:
In Step 1 of
Step 2 shows the mandrel (120) sprayed with a conventional release agent (140), suitable for releasing the formed barrel (100), depending on the composition of the resin (150).
Step 3 shows the mandrel (120) inserted into the barrel base (110).
Step 4 shows the mandrel (120) and base (110) assembly inserted into the tube (130).
Step 5 shows the mixing of a preselected resin (150). “Resin” is here taken to mean any suitable compound for molding the barrel (100).
Step 6 shows the resin (150) poured into the space between the mandrel (120) and the tube (130). Step 6 is further depicted in
Step 7 in
This application claims the priority of U.S. Provisional Patent Application Ser. No. 60/947,465, titled “Soft-Projectile Gun Barrel and Method for Making Same,” filed Jul. 2, 2007.
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Number | Date | Country | |
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20090007767 A1 | Jan 2009 | US |
Number | Date | Country | |
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60947465 | Jul 2007 | US |