From Ammoland:

Marine Corp Private Ali Akazahg was convicted of possessing two machine guns, in violation of Articles 83, 107, and 134 of the Uniform Code of Military Justice [UCMJ]. These “machine guns” that Private Akazahg processed were bump stocks. The Private’s defense counsel argued that bump stocks did not meet the federal definition of machine guns. The ruling is found here and embedded below. US Military Courts Rules Bump Stocks Are Not Machine Guns.