Tools
Recoil calculator
How hard a load kicks, in numbers you can compare. Free recoil energy is the figure the industry quotes; recoil velocity is closer to what your shoulder feels; impulse is what a muzzle brake or a heavier stock actually works against.
How it's calculated
Conservation of momentum. The gun moves back with the same momentum the bullet and the powder gas carry forward:
Vgun = (Wbullet × Vbullet + Wpowder × Vgas) ÷ (7,000 × Wgun)
E = Wgun × Vgun² ÷ (2 × 32.174)
Weights in grains for the bullet and charge, pounds for the gun; velocities in fps; energy in foot-pounds. The powder gas leaves faster than the bullet, so it is given an effective velocity of 1.75× muzzle velocity for rifles and 1.5× for handguns and shotguns — the SAAMI convention. The charge term is real: on a 300 Win Mag it is a quarter of the total, which is why leaving it blank gives a flattering answer.
What the numbers mean
- Under 10 ft·lb — 223 Remington, 243 with light bullets: shoot all day.
- 10–20 ft·lb — 6.5 Creedmoor, 7mm-08, 308, 30-06: the normal hunting rifle.
- 20–30 ft·lb — 300 Win Mag, 12-gauge field loads, 45-70: noticeable; form matters.
- 30+ ft·lb — 338 Win Mag, 375 H&H and up: most people flinch here without practice.
Two loads with the same energy can feel different: a light, fast rifle has high recoil velocity (sharp), a heavy slow one has the same energy as a push. That is why the calculator shows both.
Related
Twist rate & bullet stability · Cost per round · Cartridge reference for SAAMI velocities by bullet weight.