Patent ID: 8635797

Claim:
A rifling angle calculating method, in which rifling angle α(x), a parameter of rifling force, is calculated by expanding the rifling angle into a mathematical expression in order to minimize a maximum value of the rifling force generated between a projectile and rifling when the projectile moves along an inner surface of a gun barrel by gun barrel pressure, wherein the mathematical expression is α ⁡ ( x ) = ∑ i = 0 k ⁢ α i ⁢ x i + ∑ j = 1 l ⁢ ( b j ⁢ cos ⁡ ( j ⁢ ⁢ f ⁡ ( x ) ) + c j ⁢ sin ⁡ ( jf ⁡ ( x ) ) ) , where x denotes a distance along the length of the gun barrel from a gun breech, f(x) denotes a constant parameter, and ai, bj, and cj are constants.