A chamber reamer is a specific type of fluted reamer used by

gunsmith A gunsmith is a person who repairs, modifies, designs, or builds guns. The occupation differs from an armorer, who usually replaces only worn parts in standard firearms. Gunsmiths do modifications and changes to a firearm that may require a very h ...

s and

firearm 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 ...

s manufacturers to cut the chamber of a

handgun A handgun is a short- barrelled gun, typically a firearm, that is designed to be usable with only one hand. It is distinguished from a long gun (i.e. rifle, shotgun or machine gun, etc.), which needs to be held by both hands and also braced ...

rifle A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves ( rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with ...

, or

shotgun A shotgun (also known as a scattergun, or historically as a fowling piece) is a long gun, long-barreled firearm designed to shoot a straight-walled cartridge (firearms), cartridge known as a shotshell, which usually discharges numerous small p ...

. The chamber reamer is inserted into the bore of a

barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...

and held stationary while the barrel is turned around it (typically by means of a

lathe A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to c ...

). The reamer slowly cuts away material, leaving a chamber capable of accepting a specific cartridge.

Types

Chamber reamers come in two general types - solid pilot reamers and floating pilot reamers. A solid pilot reamer has, as the name suggests, a solid

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

pilot on the end to guide the reamer through the bore of the barrel. These reamers are generally more durable and less expensive than floating pilot reamers. Floating pilot reamers use interchangeable pilots that are positioned at the front of the reamer. The primary advantage of a floating pilot reamer is that it is self-centering and can be fitted with a pilot that is an exact match with the barrel it is passing through. Barrels tend to vary in diameter by minute amounts, and this variation can create a situation whereby the solid pilot reamer fits too loosely or too snugly in the bore. Another advantage of floating pilot reamers is that the pilot itself does not spin with the reamer, and therefore is less likely to damage the bore. The primary disadvantage of the floating point reamer is that the nose of the reamer must be cut down in diameter to accommodate the reamer pilot, resulting in a more delicate reamer.Chambering a Rifle Barrel
by Bill Marr, March 2013, in RIFLESHOOTER.COM Chamber reamers are typically made of high speed steel and require

lubrication Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology. Lubrication mechanisms such as fluid-lubric ...

during the cutting operation. A chamber reamer, regardless of pilot design, will operate most efficiently at speed of 200 to 300 RPM, and feed rate just fast enough to avoid chatter. Chamber reamers are designed with flutes to collect and extract the cut material, however these flutes must be periodically cleaned (typically after every .2" of cutting). Finally, reamers must be sharpened from time to time. Given proper care, a reamer can cut 10-15 chambers between sharpening. Manufacturers produce most chamber reamers to

SAAMI The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI, pronounced "Sammy") is an association of American manufacturers of firearms, ammunition, and components. SAAMI is an accredited standards developer that publishes several Americ ...

specifications so that any factory

ammunition Ammunition (informally ammo) is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs, missiles, grenades, land mines) and the component parts of other weap ...

can be safely used in any firearm chambered with their reamer, for a given cartridge. Most reamer manufacturers will, however, produce reamers to customer specifications. These are useful to benchrest shooter who are willing to trade off compatibility for accuracy, and by ' wildcatters' - individuals who are interested in designing completely new cartridges.

References

{{Reflist *Hoehn, Ron ''et al.''; ''Benchrest Primer'', Precision Shooter. This text contains specific articles about chambering and chamber reamers.

External links

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