Editing Chrome plating (section)

==Arms use==
Chrome-lining protects the [[Barrel (firearms)|barrel]] or [[Chamber (weaponry)|chamber]] of arms from corrosion and makes these parts also easier to clean, but this is not the main purpose for lining a barrel or chamber. Chrome-lining was introduced in machine guns to increase the wear resistance and service life of highly stressed arms parts like barrels and chambers, allowing more rounds to be fired before a barrel is worn and needs to be replaced. The end of the chamber, freebore and leade (the unrifled portion of the barrel just forward of the chamber), as well as the first few centimeters or few inches of rifling, in rifles are subject to very high temperatures—as the energy content of rifle propellants can exceed 3500 kJ/kg—and pressures that can exceed {{convert|380|MPa|psi|0|abbr=on}}. The propellant gases act similarly as the flame from a cutting torch, the gases heating up the metal to red-hot state and the velocity tearing away metal. Under slow fire conditions, the affected areas are able to cool sufficiently in between shots. Under sustained rapid fire or automatic/cyclic fire there is no time for the heat to dissipate. The heat and pressure effects exerted by the hot propellant gasses and friction by the projectile can quickly cause damage by washing away metal at the end of the chamber, freebore, leade and rifling. Hard chrome-lining protects the chamber, freebore, leade and rifling with a thin coat of wear resistant chrome. This significantly extends barrel life in arms that are fired for prolonged periods in full-auto or sustained rapid fire modes. Some arms manufacturers use [[Stellite#Applications|Stellite-lining alloy]] as an alternative to hard chrome-lining to further increase the wear resistance and service life of highly stressed arms parts.<ref>{{Cite web |url=http://www.usord.com/weapons/stellite |title=Stellite Lined Barrels |access-date=2021-09-24 |archive-date=2021-09-23 |archive-url=https://web.archive.org/web/20210923045006/http://www.usord.com/weapons/stellite |url-status=dead }}</ref><ref>{{Cite web |url=http://www.sadefensejournal.com/wp/torture-test-u-s-ordnance-mag-58m240/2/ |title=Torture Test: U.S. Ordnance MAG-58/M240 – Small Arms Defense Journal - Dan Shea - 28 February 2013 |access-date=24 September 2021 |archive-date=24 September 2021 |archive-url=https://web.archive.org/web/20210924180120/http://www.sadefensejournal.com/wp/torture-test-u-s-ordnance-mag-58m240/2/ |url-status=dead }}</ref>