Get Momentum from AddForce

I want to create a damage mechanism based upon the force applied from the bullets. I'm using raycasting to apply the force, that's not the problem, but I'm trying to have the damage scale based on the mass of the target. So, I can't just plug in the force applied. I'm wondering if there is a way to get the output of what AddForce applies after mass is included. Something like this:

    bulletforce = 10f;
    damageAmt = GetForceApplied(Player.rigidbody.addForce( new Vector3(bulletforce, 0, 0) ) )
    Player.ApplyDamage(dmgAmount);

GetForceApplied is the kind of function I'm trying to find I've been searching documentation, haven't found such a method, any help is appreciated.