Answer:
Recoil is measured in pounds or kilograms of force- over a measured period of time. How recoil is FELT is not only how hard a firearm pushes against you, but over what time interval. A push that builds up gradually will feel less than one that is quick and sharp. You will usually see it expressed as ft lbs- one foot lb is the energy of 1 lb dropping one foot. The recoil energy is most precisely measured with an electronic gauge.