guards at the prison. His skills in the machine shop permitted him to stay ahead of his assignments and allowed him time to develop his ideas for self-loading firearms. He would save paper and pencils and stay up late at night drawing plans for various firearms. His mother sent him a drafting set and technical data on guns and eventually provided him with patent attorney contacts, who were unable to help him as long as he was incarcerated. Williams designed and built four semi-automatic rifles while in prison. All four used the high-pressure gas within the breech as a cartridge was fired to operate their semi-automatic actions. The means used to accomplish this was a floating chamber containing the cartridge that channeled the gas at the front of the chamber to force the floating chamber backwards into the bolt with sufficient energy to operate the action. Rearward movement of the chamber was limited to a short stroke to impact the bolt face, in effect making the floating chamber a short-stroke gas piston. All four rifles are part of the permanent David Marshall Williams display in the North Carolina Museum of History. Commutation and parole His family started a campaign to commute his sentence, and they were joined by the sheriff to whom he had surrendered. The widow of the man he was convicted of killing was approached and agreed his sentence should be commuted if his work would help the country. The request for commutation was submitted to North Carolina Governor Angus McLean on November 22, 1927. On December 16, 1927, North Carolina Governor Angus McLean commuted the sentence from thirty years to “a minimum of ten and maximum of twenty years”. Records of the Office of Superintendent, NC State Prisons indicate Williams was "regularly discharged from the State's Prison by Expiration of Sentence" on September 29, 1929. Firearms development Back in Cumberland County, he set to work perfecting his inventions, filing his first patents on February 2, 1931. Amongst these was a patent application entitled “Automatic Firearm” published August 24, 1937. This application detailed his concept for the use of the high-pressure gas in or near the breech to operate the action of a semi-automatic firearm. The application and subsequent patent detail several different designs to accomplish this, including the floating chambers he manufactured on the four rifles he built while imprisoned. Colt Manufacturing Company In 1931, Colt Manufacturing