I have a simple technical question. I really don't want this to devolve into a pro-gel or anti-gel.match. Please limit discussion to the question posed. PLEASE! In another discussion someone brought up the fact that elasticity of skin is not really a barrier to penetration when it is backed by tissue. I also have read of the study that correlates penetration in human soft tissue including skin to gel (+/- 20%). My question is: Why does the calibration bb penetrate 3.5" into gel at a velocity that has been known to bounce off skin covered human flesh?