The term fire forming in
firearms
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes c ...
refers to the process of
thermomechanically reshaping a
metallic cartridge case to optimally fit a new
chamber 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, 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 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.
There are two methods of fire forming. One method is to cold form a parent case using forming dies, creating some form of
headspace
Headspace may refer to:
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*Headspace (organisation), an Australian non-profit organization for youth mental health
*Headspace or ullage, the unfilled space in a container
...
, 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