Drop Testing

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When firearms submitted to the crime laboratory are involved in an alleged accidental discharge case, a special test may be required. If a defect is not discovered during the basic examination that supports an accidental discharge, an additional test, called the drop test is performed.

This test enables the examiner to determine if there is a possibility the firearm will discharge if dropped. This is a time-consuming examination, which has potential to damage the tested firearm. Therefore, when necessary it should be the last examination conducted.

The results of the following drop test examination should be documented:

Place a one-inch-thick rubber pad onto a solid floor (such as concrete).
Place a primed cartridge case in the chamber that will receive the hammer strike.
Cock the firearm.
Disengage the external safety.
Drop the firearm from a height of about three feet onto the pad.
Test all positions of the firearm - top, bottom, left side, right side, rear, and muzzle. (Before each drop, the primed case should be checked for firing pin indentations and the findings recorded.)

There are two possible outcomes:

The primed case does not detonate, indicating that the firearm will not discharge when dropped.
The primed case detonates:
- Field strip the firearm.
- Examine the major internal components to determine if there are any broken or missing parts.

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