A chamber reamer is a specific type of fluted
reamer
A reamer is a type of rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides. There are also non-precisio ...
used by
gunsmiths and
firearms manufacturers to cut the
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 ...
of a
handgun,
rifle, or
shotgun. The chamber reamer is inserted into the bore of a
barrel and held stationary while the barrel is turned around it (typically by means of a
lathe). The reamer slowly cuts away material, leaving a chamber capable of accepting a specific
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 ...
.
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 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
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...
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
High-speed steel (HSS or HS) is a subset of tool steels, commonly used as cutting tool material.
It is often used in power-saw blades and drill bits. It is superior to the older high-carbon steel tools used extensively through the 1940s in tha ...
and require lubrication 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
The phrase speeds and feeds or feeds and speeds refers to two separate velocities in machine tool practice, cutting speed and feed rate. They are often considered as a pair because of their combined effect on the cutting process. Each, however, ...
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 specifications so that any factory ammunition 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
Professional & Efficient Shear Blade
Metalworking cutting tools