go into material.ini of the base.rte
and replace concrete (helmet gib) with this one
Code:
AddMaterial = Material
   InstanceName = Concrete
   Restitution = 0.6
   Friction = 0.9
   Density = 0.3
   Strength = 75
   Priority = 6
   SpawnMaterial = 0
   Color = Color
      R = 0
      G = 0
      B = 0
   UseOwnColor = 0
and flesh with this one
Code:
AddMaterial = Material
   InstanceName = Flesh
   Restitution = 0.6
   Friction = 0.6
   Density = 0.12
   Strength = 35
   Priority = 15
   SpawnMaterial = 12
   Color = Color
      R = 155
      G = 0
      B = 0
   UseOwnColor = 1
that is the default values of the game