Kinetic energy. recoil and damage

Projectile Weapons

Kinetic Energy, Free Recoil and Damage

The following is a simple for to allow GM and gearheads to quickly and easily calculate projectile weapons' Kinetic energy, free recoil energy and damage. The system for calculating damige is from T4's Fire, Fusion and Steel (2nd edition).

Free recoil is a simple and comparative measure of how much 'kick' is transmitted to the shooter. The GM may wish to take into account free recoil energy when determining if a weapon can be fired by a character of a particular strength, and where accurate follow up shots are possible.

Comparative Recoil
.22 Pistol 1.1 J .22 Rifle < 1 J Snub Pistol 2.2 J
.25 acp pistol 1.5 J .223 rifle (M-16) 5.0 J ACR HE 9.4 J
9mm Pistol 5.4 J .308 Rifle (M-14) 18 J ACR DS 7.4 J
.45 acp pistol 7.9 J 12 gauge Shotgun 30 J LAG 47.5
.44 magnum 20 J .458 Elephant Gun 75 J Gauss Rifle 5.1 J

English to Metric conversion Kinetic and Free Recoil Energy
Bullet Weight (gns) Projectile Mass (g) Import English into SI units.
Bullet Velocity (fps) Projectile Velocity (m/s) Calculate KE and RE
Propellent Weight (gns) Propellant Mass (g) Kinetic Energy (J)
Weapon Weight (lbs) Weapon Mass (kg) Recoil Energy (J)
Barrel Length (inches) Barrel Length (cm) Force Generated (N)
Traveller Statistics
TNE Damage (D6) Base TNE Recoil Base TNE Penetration
T4 Damage (D6) Base T4 Recoil

Further Notes on Recoil

It should be noted that free recoil energy is really only a comparitive look at at recoil. Felt recoil is highly subjective and is effected by a large bumber of factors. The shape and area of the weapon/firer interface (butt) plays a large role. A larger butt area means less force is applied put cubic centimeter of contact area. Felt recoil can also be reduced through the use of recoil absorbing devices like rubber butt pads, recoil absorbing springs and in the case of CPR and ETC weapons, muzzle brakes. There are also tecniques of recoil redulction the use counter masses to absorb recoil energy like open bolt weapons and so called 'soft recoil' weapons, where a large percentage of the weapon is accelerated in opposition to recoil force, nullifying a large part of the recoil generated.

If one examined the force generated in firing use F=ma where m is the mass of the projectile an a is the acceleration of said projectile withing the weapon system, one can extimate the amout of recoil force generated, and translate that to the pressure applied to the butt over a given area to get an idea of the 'shock' delivered to the firer. A quick method to determine force is to assume constant acceleration of the projectil in the barrel. As force is equal in both directions (pushing the projectile to the target and the weapon to the shooter) we can reflate F to KE of the projectile by substituting F= m*v^2/2s where s is the barrel length in meters and assuming 0 for the initial velocity. But m*v^2/2 is KE, thus we arrive at F=KE/s in newtons (kgm/s^2) over the length of time the projectile accelerates down the barrel.