to be a nerd-
Jam is normally a term that requires a tool or gunsmith to fix....
Malfunctions tend to be called Type 1.2 and 3... Its a way to let everyone know what happened...
Mechanical malfunctions[edit]
Mechanical malfunctions of a firearm (commonly called jams)
[3] include failures to feed, extract, or eject a cartridge; failure to fully cycle after firing; and failure of a recoil- or gas-operated firearm to lock back when empty (largely a procedural hazard, as "slide lock" is a visual cue that the firearm is empty). In extreme cases, an overloaded round, blocked barrel, poor design and/or severely weakened breech can result in an explosive failure of the receiver, barrel, or other parts of the firearm.
Failure to feed[edit]
Failure to feed (FTF) is when a firearm fails to feed the next round into the firing chamber. Failure to feed is common when the shooter does not hold the firearm firmly (known as
limp wristing), when the slide is not fully cycled by the preceding round, or due to problems with the magazine. It can also be caused by worn recoil springs, buffer springs, or simply a dirty feed ramp.
Rim lock[edit]
Rim lock is where the rim of the shell casing gets caught on the extractor groove of the casing underneath it. It is a common issue for calibers with large rims, such as
7.62×54mmR, or guns that have been rechambered for cartridges shorter than intended without replacing the original magazine with one that compensates for the shorter round.
Hammer follow[edit]
Hammer follow occurs when the disconnector allows the hammer to follow the bolt and firing pin into battery, sometimes causing the firing mechanism to function without pulling the trigger. This is usually a result of extreme wear or outright breakage of firing mechanism components, and can result in uncontrollable "full-auto" operation, in which multiple rounds are discharged following a single pull of the trigger.
Slamfire[edit]
Main article:
Slamfire
A slamfire is a premature, unintended discharge of a firearm that occurs as a
round is being loaded into the
chamber, when the bolt "slams" forward (hence the name), as a result of the firing pin having not been retracted into the bolt, or from the firing pin being carried forward by the momentum of returning to battery. Similar to a hammer follow malfunction, this can result in uncontrollable "full-auto" operation.
Failure to extract[edit]
A failure to extract occurs when the casing of the just-fired round is not successfully extracted from the chamber. This can be caused by an overly-dirty chamber, broken extractor claw, case rim failures, or several other causes.
Failure to eject[edit]
A failure to eject (FTE) occurs when the casing of the just-fired round is extracted from the chamber, but is not ejected from the firearm, causing the next round to fail to feed, or the slide/bolt to fail to return to battery. A stovepipe is common type of FTE.
Stovepipe[edit]
Failure to eject (FTE, "stovepipe") in a semi-automatic pistol.
A stovepipe or smokestack typically occurs in
pump action,
semi-automatic, and
fully automatic firearms that fire from a closed bolt, when an empty cartridge case gets caught partway out of the ejection port instead of being thrown clear. Stovepipes can be caused by a malfunctioning or defective extractor or ejector, or when the shooter does not hold the firearm firmly enough for the action to function fully, known as
limp wristing, or due to reloads that are not sufficiently powerful to fully cycle the action, etc.
Double feed (Type 3 Malfunction)[edit]
A double feed occurs when two rounds are picked up from the magazine and both are moved to be fed into the chamber at the same time. This is usually due to a bad magazine but can also be the result of a bad recoil spring.
Out-of-battery[edit]
Main article:
Out-of-battery
A firearm is "in-battery" when the slide/bolt is in the normal firing position. A firearm is "out-of-battery" when the slide/bolt/action is not fully seated in the normal firing position, typically because it did not cycle fully after firing (called "returning to battery"). Most modern firearms are designed to not be capable of firing when significantly out-of-battery. As such, a firearm that is out-of-battery typically cannot be fired, which is why this is a type of firearm malfunction.
A dangerous situation can occur when a chambered round fires when the firearm is out-of-battery (called an out-of-battery discharge). The cartridge casing is not sufficiently strong to contain the pressure of firing by itself; it relies on the walls of the chamber and the bolt face to help contain the pressure. When the firearm is out-of-battery, the round is not fully chambered, or the bolt face is not against the rear of the cartridge, and if the round is fired in this situation, the case will fail, causing high-pressure hot gasses, bits of burning powder, and fragments of the casing itself to be thrown at high speed from the firearm. This can be a serious hazard to the operator of the firearm, and any bystanders.
