A "Failure to Extract" occurs when the slide or bolt move backwards, but the empty cartridge case remains behind in the chamber. In this situation, a new live cartridge may sometimes be forced into the base of the old case and the slide stays open and the firearm becomes jammed. This is called a "double feed". When this happens, the firearm can be difficult to clear.
Failure to Extract. Click on image to enlarge.
In the above image, we see a failure to extract, which causes a second cartridge to "double feed" into the chamber and leave the slide opened. The magazine may get stuck and refuse to drop out of the weapon. This type of jam sometimes requires some tools to clear the problem.
There are a few reasons why this can happen:
- Dirt and corrosion: This is the #1 reason for failure to extract. Dirt or corrosion in the extractor claw or firing chamber can cause the empty cartridge to not be picked up correctly.
- Damaged extractor: A damaged or bent extraction claw may not pick up empty cartridges correctly. A weak extractor spring could also cause this malfunction to happen.
- Defective cartridge: Due to damage around the cartridge rim, the cartridge may slip off the extraction claw and remain behind in the chamber. Bulges in the cartridge could cause excess friction on the sides, which causes the cartridge to slip off the extraction claw.
A failure to extract will cause the weapon to not fire any more, until the problem is cleared. The cost of fixing this is usually not that much, as cleaning dirt is a standard procedure that should be carried out with any firearm. Damaged extraction claws and extractor springs can also be replaced fairly cheaply, as these parts are not that expensive for most firearms. Defective cartridges can be disposed off and cartridges of better quality can be purchased instead.