 It also mandated the registration of machine guns, short-barreled rifles and shotguns, heavy weapons, explosive ordnance, suppressors, and disguised or improvised firearms.In 1938, President Franklin D. Roosevelt signed the Federal Firearms Act of 1938 ("FFA") into law, requiring that all gun related businesses must have a Federal Firearms License (FFL).In 1939, through the court case United States v. Miller, the Supreme Court of the United States ruled that Congress could regulate interstate selling sawed-off shotguns through the National Firearms Act of 1934, deeming that such a weapon has no reasonable relationship with the efficiency of a well regulated militia.