I understand the 5.56 not being able to blast through doors and walls, but isn't the long long supposed to tumble on impact and breaking apart causing large hyperbolic tissue damage?
What is with this through and through finding?
The "tumbling" is associated with FMJ ball rounds, which have trouble getting thru hard cover.
The steel-cored M855 "penetrator" rounds go thru hard cover much better ... resulting them going thru soft stuff like it wasn't there.