Editing Chain gun (section)

==History==
In 1972, [[Hughes Helicopters]] began a company-funded research effort to design a single machine gun to fire the [[United States Army|U.S. Army]]'s M50 {{nobr|20 mm}} round.<ref name=R&P/><ref name=CGM/> In April 1973, the program fired test rounds in more powerful {{nobr|30 mm}} WECOM [[Belt (firearms)|linked ammunition]], from a prototype A model. In January 1975, a model "C" was added, a linkless version for the proposed [[Advanced Attack Helicopter]] YAH-64. The helicopter was later adopted as the [[Boeing AH-64 Apache|Hughes Model 77/AH-64A Apache]], with the model C receiving the designation [[M230 chain gun]] as its standard armament.<ref name=R&P/><ref name=CGM/> 

In 1976, Hughes Helicopters patented the chain gun,<ref name="USPTO" /> and it has since been further developed into several other systems of different calibers.<ref name="R&P">Richardson & Peacock, 1992, pp. 38–40.</ref><ref name="CGM">[[George Chinn|Chinn, George M.]], 1987, pp. 453–454.</ref>

[[File:Chaingun.jpg|thumb|A M242 [[Mk38#Naval|Mk 38 chain gun]] mounted on [[USS Nicholas (FFG-47)]]]]

{{As of|2019}}, "chain gun" is a registered trademark of [[Northrop Grumman Innovation Systems]], formerly Orbital ATK, following several mergers and acquisitions after Hughes Helicopters, for "externally-powered machine guns".<ref name="USPTO">{{cite web |url=http://assignments.uspto.gov/assignments/q?db=tm&qt=sno&reel=&frame=&sno=73027311 |title=Trademark Assignment Abstract of Title |publisher=[[United States Patent and Trademark Office]] |date=12 November 2018 |access-date=28 April 2019}}</ref>