Fire forming

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Fire formed .284 Achilles case (right) Cold formed .425 Westley Richards case (center) and .425 Westley Richards parent case (left) Fire forming.jpg
Fire formed .284 Achilles case (right) Cold formed .425 Westley Richards case (center) and .425 Westley Richards parent case (left)

The term fire forming in firearms refers to the process of thermomechanically reshaping a metallic cartridge case to optimally fit a new chamber by firing it within that chamber. [1] 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, 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.

See also

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Handloading, or reloading, is the practice of making firearm cartridges by assembling the individual components, rather than purchasing mass-assembled, factory-loaded ammunition.

<span class="mw-page-title-main">Headspace (firearms)</span> Insertion depth of a cartridge in a chamber

In firearms, headspace is the distance measured from a closed chamber's breech face to the chamber feature that limits the insertion depth of a cartridge placed in it. Used as a verb by firearms designers, headspacing refers to the act of stopping deeper cartridge insertion. The exact part of the cartridge that seats against the limiting chamber feature differs among cartridge and gun designs. In general, bottleneck rifle cartridges headspace on their case shoulders; rimmed cartridges headspace on the forward surfaces of their case rims; and rimless pistol cartridges headspace on their case mouths. The case belts on belted cartridges were originally added to allow headspacing on the belt's forward surface, But in practice, this is often vestigial, and rifles chambered for belted cartridges may well headspace them on their shoulders and still be within CIP or SAAMI dimensional limits. However, belted cartridges and their corresponding chambers at their nominal CIP or SAAMI dimensions will headspace on the belt.

<span class="mw-page-title-main">Wildcat cartridge</span> Custom cartridge for firearms

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 of an existing commercial cartridge, or may merely be intended as novelty items.

<span class="mw-page-title-main">7×57mm Mauser</span> German military rifle cartridge

The 7×57mm Mauser is a first-generation smokeless powder rimless bottlenecked rifle cartridge. It was developed by Paul Mauser of the Mauser company in 1892 and adopted as a military cartridge by Spain in 1893. It was subsequently adopted by several other countries as the standard military cartridge, and although now obsolete as a military cartridge, it remains in widespread international use as a sporting round. The 7×57 Mauser was a popular stalking cartridge and sporting rifles in this chambering were made by the famous British riflemakers, such as John Rigby, Holland and Holland, Westley Richards and others. British cartridge nomenclature designated caliber in inches, and the cartridge was known as the .275 bore after the measurement of a 7 mm rifle's bore across the lands. The cartridge is sometimes erroneously referred to as the ".275 Rigby", However, the original John Rigby & Sons never referred to the cartridge by that name, nor did any of UK gun trade; the Rigby association is a misconception attributed to modern American gun writers.

<span class="mw-page-title-main">6.5×55mm Swedish</span> Nordic 6mm centerfire cartridge

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<span class="mw-page-title-main">.243 Winchester</span> Rifle cartridge

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<span class="mw-page-title-main">.280 Remington</span> US rifle cartridge

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<span class="mw-page-title-main">8×68mm S</span>

The 8×68mm S rebated rim bottlenecked centerfire rifle cartridge was developed in the 1930s by August Schüler of the August Schüler Waffenfabrik, Suhl, Germany as a magnum hunting cartridge that would just fit and function in standard-sized Mauser 98 bolt-action rifles. The bore has the same lands and grooves diameters as the German 7.92×57mm Mauser service cartridge. This is one of the early examples where a completely new rifle cartridge was developed by a gunsmith to fit a specific popular and widespread type of rifle.

<span class="mw-page-title-main">.257 Roberts</span> Rifle cartridge

The .257 Roberts, also known as .257 Bob, is a medium-powered .25 caliber rifle cartridge. It has been described as the best compromise between the low recoil and flat trajectory of smaller calibers such as the 5 mm and 6 mm, and has more energy, but is harder recoiling, similar to larger hunting calibers, such as the 7 mm and 7.62 mm.

<span class="mw-page-title-main">Commission internationale permanente pour l'épreuve des armes à feu portatives</span>

The Commission internationale permanente pour l'épreuve des armes à feu portatives, commonly abbreviated C.I.P., is an international organisation which sets standards for safety testing of firearms. As of 2015, its members are the national governments of 14 countries, of which 11 are European Union member states. The C.I.P. safeguards that all firearms and ammunition sold to civilian purchasers in member states are safe for the users.

The following are terms related to firearms and ammunition topics.

<span class="mw-page-title-main">.284 Winchester</span> US rifle cartridge

The .284 Winchester is a firearm cartridge, introduced by Winchester in 1963.

<span class="mw-page-title-main">P. O. Ackley</span> Gunsmith, author and columnist (1903–1989)

Parker Otto Ackley was an American gunsmith, barrel maker, author, columnist, and wildcat cartridge developer. The Ackley Improved family of wildcat cartridges are designed to be easily made by rechambering existing firearms, and fireforming the ammunition to decrease body taper and increase shoulder angle, resulting in a higher case capacity. Ackley improved not only standard cartridges, but also other popular wildcats, and was the first to create a .17 caliber (4.5 mm) centerfire cartridge.

<span class="mw-page-title-main">.219 Zipper</span> Rifle cartridge

The .219 Zipper cartridge was created by Winchester Repeating Arms in 1937 to be used in their lever-action Model 64 rifle. It is a 30-30 Winchester cartridge necked down to a .22 caliber bullet. Marlin Firearms also offered their Marlin Model 336 rifle chambered for the cartridge.

<span class="mw-page-title-main">.30-06 Springfield wildcat cartridges</span> Non-standard rifle cartridge

.30-06 Springfield wildcat cartridges are cartridges developed from a 30-06 Springfield "parent cartridge" through narrowing or widening the cartridge neck to fit a smaller or larger bullet in an attempt to improve performance in specific areas. Such wildcat cartridges are not standardized with recognized small arms standardization bodies like the SAAMI and the CIP.

The 6.5-06 A-Square is a centerfire rifle cartridge that originated as a wildcat, based on the popular .30-06 Springfield. A-Square standardized the dimensions of the cartridge and submitted them to SAAMI in 1997.

<span class="mw-page-title-main">Dick Casull</span>

Richard J. Casull was a Salt Lake City-born gunsmith and wildcat cartridge developer whose experiments with .45 Colt ammunition in the 1950s led to the creation of the .454 Casull cartridge. Casull's passion was six-shooters, and he was determined to create a high velocity round for the .45 Colt. His goal was to achieve a muzzle velocity of 2,000 feet per second with Colt .45 rounds fired from a single-action Army-style revolver with a 7+12inch barrel. This proved impossible due to the tensile strength of the Colt .45 cylinder, so he set out to develop his own casing and bullet.

References

  1. Glenn Newick, "The Ultimate in Rifle Accuracy", Stroger Publishing Company, 1989. ISBN   0-88317-159-7