M855: question for the experts

[lone-wolf]

Couple questions.
What's with the outlines? I assume the shaded area is the actual bullet path?
It shows cm of penetration, with lines going up from 20 & 30, what do they mean?

 

[foxbat]

I believe the extra lines are demonstrating the contrasting diameter of the permanent wound channel.

 

[troopasaurus]

The blue and yellow lines are for the width of the average human torso.
Shaded area is permanent cavity, outer line is temporary cavity (how far the flesh will stretch as the round passes through before relaxing back into the permanent cavity).

What can we note from the above? well for example the 7.92's second tumble would have likely taken place after exiting and thus not really having any use unless its a thick individual or your shooting down the length of the torso.