Can you please provide a link to the data you are citing?
None in the public realm that I'm aware of. Sorry.
Also the body is comprised of tissue that is not just soft...bone, cartliage.
Understood.
JHP bullets are designed to expand in soft tissues. Soft tissues contain the fluids required to produce hydrostatic pressure in the cavity which causes the cavity walls to spread outward expanding the annular ring.
In a defensive shooting the kinds of tissues we’re trying to destroy are all soft tissues. These are reasons why bone isn’t normally used to test JHP bullet performance because: 1) JHP bullets aren’t designed to expand in bone – they just deform, and 2) the bullet’s terminal performance characteristics are entirely dependent on factors that cannot be controlled by the shooter (what bone is hit, where it is hit, angle of impact, depth of location along the wound track, bone density/thickness, etc.). The only terminal performance desired in bone is for the bullet to blast through to reach vital soft tissues. Quite simply, performance in bone is what it is.
Rib bones affect terminal performance very little because they aren't "solid" bone. Other than ribs, hand/wrist/arm bones, shoulder bones, spinal bones and the cranium are about the only bones your bullet is likely to encounter in a defensive shooting when you target the torso and head.
Modern JHP bullets expand completely after about an inch of penetration in soft tissues. Unless solid bone is encountered within the first inch of penetration the bullet will usually expand just like it does in ordnance gelatin. If it encounters bone after the first inch or so, bone will merely deform the already expanded bullet.
In regard to various soft tissue densities and resistance to bullet penetration:
"When a bullet is penetrating any material (tissue, water, air, wood, etc.), the total force the bullet exerts on the material is the same as the total force the material exerts on the bullet (this is Newton’s Third Law of Motion). These forces may be represented as a combination of shear forces and inertial forces (don’t be concerned if these words sound too technical – the concepts are easy). Shear force may be thought of as the force that resists deformation; if you push on a wall you are creating shear forces in the wall material that resist your push. If you push your hand down very slowly on a water surface, you feel no resisting force; this is true because a liquid cannot support a shear force….
"You can fan your hand back and forth in air quite rapidly because there seems to be no resistance, but a similar fanning motion cannot be done nearly as rapidly underwater because moving the water can take all the strength you can muster. The forces that resist the movement of your hand in water are inertial forces….
"A bullet penetrating a soft solid (tissue or a tissue simulant like gelatin) meets resistance that is a combination of shear forces and inertial forces….
"…Anyone who has worked with gelatin knows that a finger can be pushed into gelatin with a force of only a few pounds; this force is similar to the resistance to a finger poked into the stomach, but the tissue does not fracture as easily as gelatin does. A finger poked into water does not meet this kind of resistance, which is due to shear forces. Penetration of a 9mm bullet at 1000 ft/sec is resisted by an inertial force of about 800 pounds; it is obvious that the presence or absence of a 3 to 5 pound shear force makes no practical difference in the penetration at this velocity. This also explains why the fact that gelatin fractures more easily than tissue does is not important.
"The extension of these dynamics to soft tissue variation is obvious. Different types of tissue present different resistance to finger probing by a surgeon, but the surgeon is not probing at 1000 ft/sec. Different tissue types do have differences in the amount of shear force they will support, but all of these forces are so small relative to inertial forces that
there is no practical difference. The tissue types are closer to one another than they are to water, and bullet expansion in water and tissue are nearly identical at velocities over 600 ft/sec where all bullet expansion takes place (See Bullet Penetration for a detailed explanation of bullet expansion dynamics).
"Since inertial forces depend on accelerating mass, it makes sense that these forces should be lower at lower velocities (because the penetrated material cannot be accelerated to a velocity higher than the bullet). Shear forces have little velocity dependence, and as a result, shear forces are a much larger fraction of the total when bullet velocity is below the cavitation threshold. This low velocity effect is the reason that total bullet penetration depth is much different in water and in tissue or a valid tissue simulant.
"As a result of the penetration dynamics, most soft solids with a density very near soft tissues (i.e., near the density of water) are satisfactory tissue simulants when shear forces are not important. However, total penetration depth depends significantly on dynamics at velocities below 400 ft/sec, so most materials do not properly simulate penetration depth. The total bullet penetration depth in tissue and a valid tissue simulant should be the same; standard practice is to use calibrated gelatin to insure this. In effect, gelatin calibration is done to ensure that the shear forces in the gelatin are the same as in typical soft tissue (as described in Bullet Penetration, the technical parameter used in the dynamic is viscosity)."
-- MacPherson, Duncan: "Wound Ballistics Misconceptions": Wound Ballistics Review, 2(3): 1996; 42-43
