Unfortunately, humans are not made of Jello. They have pesky obstacles such as hands or arms, bone, muscle and clothing in the way.
Exactly. This is why the FBI protocols were developed as they are. Swine ribs which are actually tougher than human ribs were incorporated into the original testing but there were virtually no differences in bullet performance between gel with ribs and without, so the ribs were dropped. In addition, the 1994 Canadian ballistics testing with ribs further confirmed that ribs were really not needed in the testing. If anything, the Canadian test showed that heavier bullets with better sectional density were superior to light and fast loads. Then of course you have the problems of skull deflection which were deemed most accurately simulated with the windshield tests.
Here's an explaination of Winchester's Ranger Bonded testing according to FBI protocols:
All testing is done in accordance with the standardized FBI protocols. The bare gel test involves 10% ballistic gel calibrated to mimic human muscle tissue. The other tests involve placing various materials in front of the bare gel to demonstrate what it would be like to shoot someone through such materials. After the bullet punches through these barriers it may become damaged /deformed or plugged with material(wood/cloth) which will reduce its expansion capabilities. When a hollow point expands it acts like a parachute reducing penetration. If it is damaged or plugged it may not expand very well which results in deeper penetration with less expansion. The FBI has done continued testing of ammunition for two decades and they take into account the results of actual street shootings and how that ammunition behaved against an actual person and/or barrier. With that knowledge, they still recommend that you use ammunition that achieves a minimum penetration depth of 12” in bare gel. They also conclude that good penetration is always more important than expansion, but as long as 12” of penetration can be maintained every bit of expansion improves terminal damage effects.
FBI Test Protocol:
Bare Gelatin = covered with T-shirt, Shot at 10ft
Denim = 4 layers shot at 10ft
Heavy Clothing = shot at 10ft
Steel = 2 pieces of 20 gauge, shot at 10ft
Wallboard = 2 pieces of 1/2" gypsum board, shot at 10ft
Plywood = 1 piece of 3/4" AA fir plywood, shot at 10ft
Automobile Glass = 1 piece of 1/4" laminated safety glass set at a 45 degree angle with an offset of 15 degrees, shot at 10ft
9mm+P 124gr(1180fps)BONDED: (Penetration/Expansion)
Bare Gel: 12.6”/.68”
Through Denim: 18.7”/.54”
Through Heavy Cloth: 18.2”/.56”
Through Wallboard: 11.9”/.64”
Through Plywood: 15.8”/.57”
Through Steel: 22”/.42”
Through Auto Glass: 12.7”/.58”
9mm 147gr(995)BONDED: (Penetration/Expansion)
Bare Gel: 14.7”/.62”
Through Denim: 16.5”/.59”
Through Heavy Cloth: 15.8”/.58”
Through Wallboard: 16.7”/.56”
Through Plywood: 16.5”/.59”
Through Steel: 19”/.42”
Through Auto Glass: 12.6”/.55”
.357sig 125gr(1350fps)BONDED: (Penetration/Expansion)
Bare Gel: 12.5”/.59”
Through Denim: 15.9”/.57”
Through Heavy Cloth: 16.9”/.55”
Through Wallboard: 14.7”/.62”
Through Plywood: 16.0”/.60”
Through Steel: 21.7”/.44”
Through Auto Glass: 12.8”/.62”
.40S&W 180gr(1070fps)BONDED: (Penetration/Expansion)
Bare Gel: 14.8”/.67”
Through Denim: 21.8”/.51”
Through Heavy Cloth: 19”/.59”
Through Wallboard: 16.7”/.61”
Through Plywood: 15.5”/.62”
Through Steel: 14.8”/.55”
Through Auto Glass: 12.4”/.63”
.45acp 230gr(905fps)BONDED: (Penetration/Expansion)
Bare Gel: 14”/.73”
Through Denim: 15.8”/.67”
Through Heavy Cloth: 15.8”/.68”
Through Wallboard: 14.7”/.69”
Through Plywood: 16.5”/.74”
Through Steel: 14.8”/.56”
Through Auto Glass: 12.5”/.66”