Ok, here we go. The following is a little game for illustration.

It is very simplified and does not represent reality very good.

My figure of merit (FOM) is: Volume of displaced tissue (e.g. how "big" is the bullet tunnel)

This is distance traveled * cross section (FOM = s_p * A)

Model: The projectile comes. For penetration you need a bit of energy to get through the skin. This energy is proportional to the cross section of the projectile (delta_E = A * k). This energy is lost there.

Then it travels through the body (size: d_body). In the body, the projectile is decelerated proportional to its cross section (F = - k_tilde * A)

If it has enough initial energy, it will come out on the other side. Otherwise it will stop.

For the math see the appended picture. (You'll have to deal with my handwriting

)

Result: your FOM is maximized if the projectile is just small enough to completely penetrate. If it is larger it loses more energy when initially penetrating, if it is smaller it goes through and creates a smaller tunnel.

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The FOM's (yes you defined two

) that you defined are very difficult to translate into math and to model. I can't do it within a reasonable time frame. The FOM I defined above would most probably correspond to something like

"caused blood loss" or "percentage of muscle in limb destroyed". It does not take pure shock (e.g. hitting it with a club), cavitation (bullet) and all these other effects into account. Also, the boar is just an unstructured lump of meat and nothing more (no brain, lungs, etc.).