Why is the hole where a bullet enters smaller than where it exits?
Physics, plain and simple.
Why is the hole where a bullet enters smaller than where it exits?
Drop a pebble into water. in the blink of an eye, the pebble displaces water, causing a literal ripple effect, and tunnels its way down through the water until it stops on the bottom of the creek bed, etc.
The ripples help illustrate what is referred to, in terms of wound ballistics, as the temporary stretch cavity. The wound channel opens outward as the projectile passes through then closes back on itself as the outward force dissipates.
This temporary cavity is driven primarily by energy/velocity; the more of it that is present, the more violent the temporary cavitation.
This effect is evident in living tissue, as opposed to other media, such as clay, mud or ballistic gelatin, where the energy transferred results in a wound cavity often many times larger than the bullet passing through it.
The large exit holes often are perhaps the most dramatic display of the sheer energy unleashed by a bullet.
The other aspect of a bullet's destruction, the permanent expansion cavity, is the result of what the bullet actually touches on its path through the target.
This is dependent on the actual bullet construction and other physics factors. Lead is unless hard-cast, is probably the most uniform ingredient to be found across various ammo.
Whereas jacketing is very proprietary from manufacturer to manufacturer. Jacketed hollow-points are designed to expand, or mushroom open, as they encounter hydrodynamic force.
The more they expand, larger the permanent wound cavity. This expansion may also enhance the temporary stretch cavity.
Why is the hole where a bullet enters smaller than where it exits?
Why is the hole where a bullet enters smaller than where it exits?
Drop a pebble into water. in the blink of an eye, the pebble displaces water, causing a literal ripple effect, and tunnels its way down through the water until it stops on the bottom of the creek bed, etc.
The ripples help illustrate what is referred to, in terms of wound ballistics, as the temporary stretch cavity. The wound channel opens outward as the projectile passes through then closes back on itself as the outward force dissipates.
This temporary cavity is driven primarily by energy/velocity; the more of it that is present, the more violent the temporary cavitation.
This effect is evident in living tissue, as opposed to other media, such as clay, mud or ballistic gelatin, where the energy transferred results in a wound cavity often many times larger than the bullet passing through it.
The large exit holes often are perhaps the most dramatic display of the sheer energy unleashed by a bullet.
The other aspect of a bullet's destruction, the permanent expansion cavity, is the result of what the bullet actually touches on its path through the target.
This is dependent on the actual bullet construction and other physics factors. Lead is unless hard-cast, is probably the most uniform ingredient to be found across various ammo.
Whereas jacketing is very proprietary from manufacturer to manufacturer. Jacketed hollow-points are designed to expand, or mushroom open, as they encounter hydrodynamic force.
The more they expand, larger the permanent wound cavity. This expansion may also enhance the temporary stretch cavity.