Bullets and Car Metal

Below is an example of the effects of bullet construction materials and powder loads upon the damage to an automobile fender.  The plain lead bullets will deform (flatten) when they meet the same resistance as jacketed (metal wrapped) bullets that tend to keep their shape.

 As the plain lead (or hollow point bullet) deforms, it increases in diameter and transfers energy to the metal causing it to dent “inward” resulting in a crater.  That crater is highlighted by the paint broken free from its bond to the underlying metal.  The measured diameter of the resulting bullet hole will be greater than the nominal caliber (diameter) of the bullet.

A general rule of thumb is: “The greater the crater, the greater the diameter of the bullet hole will be than the original nominal caliber.  The flattening bullet is pushing the metal target and deforming to become wider than it’s original diameter.

For Example: (with lead bullets)

A .22 caliber may leave a .30 caliber hole.

A .38 caliber (or 9mm) may leave a .45 caliber hole.

A  .45 (or .44) may leave a hole greater than one-half inch in diameter!