The term fire forming in
firearms refers to the process of
thermomechanically reshaping a
metallic cartridge
A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile (bullet, shot, or slug), a propellant substance (usually either smokeless powder or black powder) and an ignition device (primer) within a metallic, p ...
case to optimally fit a new
chamber
Chamber or the chamber may refer to:
In government and organizations
* Chamber of commerce, an organization of business owners to promote commercial interests
*Legislative chamber, in politics
* Debate chamber, the space or room that houses delib ...
by firing it within that chamber.
[Glenn Newick, "The Ultimate in Rifle Accuracy", Stroger Publishing Company, 1989. {{ISBN, 0-88317-159-7] This might expand a cartridge to a new size, such as a
wildcat cartridge
A wildcat cartridge, often shortened to wildcat, is a custom cartridge for which ammunition and/or firearms are not mass-produced. These cartridges are often created in order to optimize a certain performance characteristic (such as the power, si ...
, or just to the chamber of a specific gun.
Fire forming a wildcat differs from the normal manufacturing process; in that it relies on firing a loaded
cartridge
Cartridge may refer to:
Objects
* Cartridge (firearms), a type of modern ammunition
* ROM cartridge, a removable component in an electronic device
* Cartridge (respirator), a type of filter used in respirators
Other uses
* Cartridge (surname), a ...
of differing dimensions than the chamber which it is being fired in. After fire forming, the spent case will take on the new dimensions of the firearm's chamber. Fire forming is the final process in creating a wildcat or an
improved cartridge
A wildcat cartridge, often shortened to wildcat, is a custom cartridge for which ammunition and/or firearms are not mass-produced. These cartridges are often created in order to optimize a certain performance characteristic (such as the power, si ...
.
There are two methods of fire forming. One method is to cold form a parent case using forming dies, creating some form of
headspace, load the case and fire the cold formed cartridge in the chamber of the firearm. This first method is the most common and will create a wildcat cartridge. The second method is to fire form a factory cartridge by using its factory headspace to headspace on. The factory cartridge is then fired in the chamber of the firearm. This second method will create an improved cartridge.
References
*Parker O. Ackley, ''Volume 1 Handbook for Shooters & Reloaders'', Plaza Publishing, 1962; 17th printing, 1988.
Ammunition
Wildcat cartridges