How so? Winchester claims to use M193-spec projectiles in their Q3131. I'm a bit befuddled as how Q3131 can perform like XM193 in newspaper but differently from XM193 in gelatin or people.
Their bullet construction are not radically different: 55gr, FMJ, exposed lead base, boat tail, canalure, and thin jacket. Q3131 is loaded hotter than SAAMI-spec .223 with a muzzle velocity approaching M193-spec as is XM193. To me, Q3131 performing like XM193 in newspaper would imply Q3131 performing like XM193 in gelatin, wood, auto glass, people, dry wall, ect. as it seems that Q3131 and XM193 behave similarly when exposed to identical circumstances (newspaper).
Newspaper and people and gelatin are not the same- you are right in that regard. However, I contend they all have common factors that play with the bullet such as elasticity, compressability, density, temperature, hardness, ect. Those factors differ in extent across each medium but they are all identical in kind allowing for a valid analogy. Elasticity is elasticity in newspaper or gelatin. If the elasticity in newspaper affects Q3131 like XM193, elasticity in gelatin should affect Q3131 like XM193.
For the sake of argument, let's pretend that any test meant to confirm performance in people allows us to fire projectiles through a medium in an identical and repeatable fashion- sort of like if we had multiple copies of the same generic human body, a luxury we don't have and the reason for ballistic gelatin.