Recoil Energy Calculator

Published recoil figures assume a rifle weight nobody prints and a load nobody states, which is why two numbers from two sources can never be compared. Enter your own four inputs and the solver returns free recoil energy, recoil velocity and impulse for your rifle — then takes any advertised reduction percentage and shows what it implies under each of the two things it could have measured.

Projectile weight (grains)

Printed on the box — 55, 62, 77, 168.

Powder charge (grains)

Factory ammunition rarely prints it — use your load data, or the typical charge for the cartridge.

Muzzle velocity (fps)

Chronographed from your own barrel if you have it. Box figures come from a test barrel whose length is rarely stated.

Rifle weight (lb)

As it comes to the shoulder: optic, mount, sling, loaded magazine.

Advertised recoil reduction (%) — optional

Type in a muzzle device’s marketing figure and we will re-derive what it actually implies at your rifle.

Declared reference conditions.This is the free-recoil case: rigid body, no shoulder, no buffer cycle, no muzzle device. Ejecta momentum = (projectile grains × muzzle velocity + charge grains × 4700ft/s) ÷ 7000; recoil velocity = that momentum ÷ rifle weight; energy = ½mv² with g = 32.174 ft/s²; impulse = momentum ÷ g. The 4700 ft/s term is the conventional effective gas velocity for smokeless powder and is printed here so that every figure on this page can be reproduced, audited or argued with.