Muzzle energy is the kinetic energy of a bullet as it is expelled from the barrel of a firearm. It provides a rough estimate of its potential destructive power.
Let’s calculate the muzzle energy of a .44 Magnum bullet.

Assumptions

Bullet mass $m$: The .44 Magnum weighs between 180 and 340 gr, depending on the ammunition. For this calculation, let’s assume a 240 gr bullet, which is equivalent to 15.56g or 0.01556 kg.

Muzzle velocity $v$: A typical 240gr bullet can achieve a muzzle velocity of 1180 ft/s. Since 1 ft/s=0.3048 m/s, this converts to approximately 360 m/s.

Calculation

The kinetic energy is calculated using the formula:

While muzzle energy provides an estimate of a bullet’s killing power, approx. 1000 J might not seem like a large amount. Yet, it is enough to cause serious injury.

Reference

https://ammo.com/ballistics/44-magnum-ballistics
http://www.ballistics101.com/44_magnum.php