Description of Jams

Failure to Fire:

Simply put the trigger is pressed and the gun does not fire.  While this is normally a cartridge malfunction it can sometimes be indicative of an issue with the firearm itself.  This is also known as a light strike.

Failure to Feed:

A failure to feed occurs when, on the slide's/bolt's forward stroke, the cartridge in the magazine does not full enter the chamber and the gun does not go into battery. 

FailureToExtract.jpg

Failure to Extract:

The spent cartridge is not pulled out of the chamber and either remains in the chamber fully or partially leading to what is known as a double feed.

Double Feeding:

The action of the firearm tries to load a new round into the chamber but the spent cartridge remains in the action causing a jam.

Failure to Eject:

The cartridge fails to be thrown clear of the action on the ejection cycle.  This results in what is sometimes known as a stovepipe jam where the spent casing ends up trapped between the breach and rear of the chamber with the majority of the case sticking out of the ejection port.