How does a bullet the size of a pencil tip leave an exit hole the size of a fist?
In: Physics
When the exit hole is larger than the bullet, the bullet doesn’t just pass through the object. It compresses the stuff of the object in its path, and that stuff drags the surrounding stuff forward (because the molecules of a solid object are linked together). As that stuff breaks away and moves forward, it drags its neighboring stuff forward too, creating an increasingly wider path of destruction until the energy of impact is used up or the bullet and displaced stuff exit the object.
ELI5? The bullet isn’t doing most the damage. It’s the pressure behind the impact. All of that energy has to go somewhere.
Once the bullet has entered the body, the flexible tissue of the body slows the bullet down due to its elasticity. The tissue gets compressed (gets mashed in) due to the impact of the bullet, but it also gets dragged along with the bullet. Since the tissue is elastic, it drags more of itself (tissue) along with it. It is almost like punching a stretched bedsheet on a mattress. The mattress will get compressed as it absorbs the force of your fist, the fist shall slow down, and the mattress shall deform into a decompression (or a bulge seen from the other side) because the elasticity would cause the mattress and sheet material to be dragged with the fist before being punctured and torn.
In your body, the bone, marrow, muscles and other viscera is like the stretchy mattress. It slows the bullet down, and forms a bulge ahead of the bullet. When the stretchiness gives way, all the material that was under stress due to being pulled forth by the bullet gets torn. And the tear is uneven and rough. That’s why exit wounds are not as smooth or small as the entry wounds.
Needless to say that the decreased spin of the bullet also causes it to waver more once inside the body, which also causes the puncture not to be from the pointy nose (which anyway gets flattened often as soon as it hits the viscera).
Depends on the bullet and what it hits. A dum dum round makes a big hole if it exits, a big round hitting bone can make a big hole, whereas a small, high velocity round designed to pierce and stay in one piece might make a small exit hole through soft tissue.
The molecules of the material you’re shooting are bound to one another, so if you move one, you move another, and another, and so on. It’s like poking a curtain. You only poke the curtain in one place, but the fabric around also starts to move.
Latest Answers