10Ring
07-10-2010, 12:26 PM
"The formula for calculating the ballistic coefficient for bullets only is as follows:
BC=SD/i
where:
BCBullets = ballistic coefficient
SD = sectional density, SD = mass of bullet in pounds or kilograms divided by its caliber squared in inches or meters; units are lb/in2 or kg/m2.
i = form factor, i = ; (CG ~ 0.5191)
CB = Drag coefficient of the bullet
CG = Drag coefficient of the G1 model bullet
M = Mass of object, lb or kg
d = diameter of the object, in or m
This BC formula gives the ratio of ballistic efficiency compared to the standard G1 model projectile. The standard projectile originates from the "C" standard reference projectile defined by the German steel, ammunition and armaments manufacturer Krupp in 1881.[3] The G1 model standard projectile has a BC of 1.[4] The French Gavre Commission decided to use this projectile as their first reference projectile, giving the G1 name.
A bullet with a high BC will travel farther than one with a low BC since it will retain its velocity better as it flies downrange from the muzzle, will resist the wind better, and will “shoot flatter” (see external ballistics)." WIKIPEDIA
Since the .230 grain .45ACP and the 300 grain .50GI bullets have nominnally the same value of i, and the .50GI has a 6% advantage in SD, the .50GI is not hindered in its velocity retention because of its 24% larger cross-sectional area.
BC Explained (www.snipersparadise.com/ballistics/coefficients.htm)
BC=SD/i
where:
BCBullets = ballistic coefficient
SD = sectional density, SD = mass of bullet in pounds or kilograms divided by its caliber squared in inches or meters; units are lb/in2 or kg/m2.
i = form factor, i = ; (CG ~ 0.5191)
CB = Drag coefficient of the bullet
CG = Drag coefficient of the G1 model bullet
M = Mass of object, lb or kg
d = diameter of the object, in or m
This BC formula gives the ratio of ballistic efficiency compared to the standard G1 model projectile. The standard projectile originates from the "C" standard reference projectile defined by the German steel, ammunition and armaments manufacturer Krupp in 1881.[3] The G1 model standard projectile has a BC of 1.[4] The French Gavre Commission decided to use this projectile as their first reference projectile, giving the G1 name.
A bullet with a high BC will travel farther than one with a low BC since it will retain its velocity better as it flies downrange from the muzzle, will resist the wind better, and will “shoot flatter” (see external ballistics)." WIKIPEDIA
Since the .230 grain .45ACP and the 300 grain .50GI bullets have nominnally the same value of i, and the .50GI has a 6% advantage in SD, the .50GI is not hindered in its velocity retention because of its 24% larger cross-sectional area.
BC Explained (www.snipersparadise.com/ballistics/coefficients.htm)