Squib load
Encyclopedia
A squib load, also known as a squib round, pop and no kick, or just a squib, is a firearm
Firearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...

s malfunction
Firearm malfunction
A firearm malfunction is the partial or complete failure of a firearm to operate as intended. Malfunctions range from temporary and relatively safe situations, such as a casing that didn't eject, to potentially dangerous occurrences that may permanently damage the gun and cause injury or death...

 in which a fired projectile does not have enough force behind it to exit the barrel, and thus becomes stuck. This type of malfunction can be extremely dangerous, as failing to notice that the projectile has become stuck in the barrel may result in another round being fired directly into the obstructed barrel
Gun barrel
A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....

, resulting in a catastrophic failure
Catastrophic failure
A catastrophic failure is a sudden and total failure of some system from which recovery is impossible. Catastrophic failures often lead to cascading systems failure....

 of the weapon's structural integrity.

Causes

Squib rounds are possible in all black powder and smokeless powder
Smokeless powder
Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder which they replaced...

 based projectile weapons. They are most often caused by negligence in the powder loading process (insufficient powder load), or a failure of the primer to ignite the powder at all. While this occurs most often because of handloading
Handloading
Handloading or reloading is the process of loading firearm cartridges or shotgun shells by assembling the individual components , rather than purchasing completely assembled, factory-loaded cartridges...

 by inexperienced reloaders, squib loads are known to occur even in reputable factory brands. Other causes include deformed bullets and attempting to fire a bullet which is slightly too large for the barrel, although both of these scenarios would more likely result in some variety of catastrophic failure
Catastrophic failure
A catastrophic failure is a sudden and total failure of some system from which recovery is impossible. Catastrophic failures often lead to cascading systems failure....

 instead of a squib.

Recent tests by the popular television show MythBusters
MythBusters
MythBusters is a science entertainment TV program created and produced by Beyond Television Productions for the Discovery Channel. The series is screened by numerous international broadcasters, including Discovery Channel Australia, Discovery Channel Latin America, Discovery Channel Canada, Quest...

have shown http://mythbustersresults.com/episode43 that the likelihood of a catastrophic failure caused by a squib load is not always guaranteed. This obviously depends on the quality of the weapon in use, the caliber, type of load (e.g. buckshot vs slug), and the location of the obstructing bullet in the barrel. Their tests were done using a shotgun, which failed to disintegrate even when the barrel had a four-inch spike welded into it.

Diagnosis

Signs that a squib round has occurred include: a much quieter or otherwise unusual-sounding discharge noise, http://www.saami.org/glossary/display.cfm?letter=L lighter or nonexistent felt recoil force, discharge of smoke from the ejection port instead of the barrel, and a failure of the action to cycle (in semi-automatic firearms). That is why it is also referred to as "pop and no kick"http://everything2.com/index.pl?node_id=1535169.

Additional links

For a textbook example of a squib load in a Sig-Sauer 9mm handgun, see http://www.thegunzone.com/squib.html.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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