Hmmmm so they are dependent upon Hydraulic dynamics? I'll have to think on that for a bit and maybe brush up on my physics a tiny bit to figure out how that would work. Maybe the resistant pressure placed on the OUTSIDE of the bullet while passing through a solid material then when it enters a fluidic region the fluid enters into the hollow point and creates the needed force through hydraulics to open and separate the petals. Okay damnit now my head hurts! And it suddenly got smokey in here!