Joined

·
2,883 Posts

I thought this would be useful information to those that might not be as familiar with reloading and ballistic data as others. You can use the equation below and plug in you own data to find the energy of the particular ammo you choose.

Foot pound of energy is calculated from Muzzle velocity squared multiplied by the bullet weight in grains divided by 450240. (4502420 is the only constant in this equation)

Example: 9mm Federal 124gr. Hydro Shock ammo

124 gr. w/ 1120 muzzle velocity

1120 x 1120 x 124 = 155,545,600 / 450240 = 345.47 foot pounds of energy.

Example: 9mm Federal 135gr. Hydro Shock ammo

135 gr. w/ 1060 muzzle velocity

1060 x 1060 x 135 = 151,686,000 / 450240 = 336.90 foot pounds of energy.

An interesting side note is that a heavier bullet will carry more energy at longer distances. In most cases at distances beyond 50 yards (impractical for most handguns) lighter weight projectiles will not produce the same kinetic energy of a heavier one.

At 25 yards, according to Federal’s velocity data the 135gr. round overtakes the lighter 124gr. bullet. As the caliber increases the yardage typically increases too.