Rifling Techniques

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people can operate the machines and make the tooling. Some examples of a gun manufacturer is Colt.

Scrape method is single + cutters on a carrier rod that is pushed and pulled to form and even number of grooves. Mainly used by muzzle-loading and custom gun makers.

Electro Chemical Machining (ECM) uses electricity as a modern manufacturing process. ECM uses hard material that cannot be machined by other more mechanical processes. There are no sparks are generated between the cathode and anode. The hardened barrels are then placed in the ECM machine and held stationary. The electrode is a plastic cylinder with metal strips circling around the exterior. ECM is a highly sophisticated machining process in that electrical and chemical energy are the cutting edges of the tool. The advantages of the process that can be used to machine hard material like hard steel and titanium alloys. The machine produces no heat or stress on the barrel during the rifling process. The disadvantages are that these machines have high tooling cost and also use large amounts of electricity. Since 1993, Smith & Wesson has been using ECM to manufacture most of their revolver barrels.

Electric Discharge Machining (EDM) is a process consists of removing material from a work piece by means of electrical sparks. EDM was invented in 1943 by two Russian scientists, Dr. B.R. Lazarenko and Dr. N.I. Lazarenko. The process involves the object to be machined and connected to a source of electricity. When the two electrodes are brought close to each other, the intensity of the electric field becomes higher than what the dielectric medium can contain and hence it breaks down. The entire process is automated and the tool electrode is moved by means of a computer numerically controlled machine. The advantages of using EDM for rifling are that it can be used on very hard materials. There is no heat or stress developed in the barrel as a side-effect of this process and no burring. The disadvantages of this approach are that it is a pretty slow process and also consumes a lot of electricity. An EDM machine is very expensive to purchase.

Polygonal rifling is a traditional lands and grooves in a rounded polygonal pattern, usually a hexagon or octagon. Polygons with a larger number of edges provide a better gas seal in relatively large diameter polygonally rifled bores. Joseph Whitworth, British engineer invented the polygonal barrel in 1853. The British military rejected Whitworth’s polygonal rifled designs. Whitworth believed his invention could be used to create a more accurate rifled musket to replace the Pattern 1853 Enfield. The advantages of polygonal rifling is it provide a better gas seal around the projectile as polygonal bores tend to have a slightly smaller bore area. Less bullet deformation and prolonged barrel life. Polygonal rifling prevents the forensic firearms examiner from microscopically measuring the width of land and groove impressions because the lands and grooves have a rounded profile instead of a well-defined rectangular profile. Some examples of a gun manufacturer is Glock.