Per "Maximum Mike":
Per Len Savage:
The upper assembly of the Fabrique Nationale Herstal SA (FN) FNC rifle is classified as the receiver of the firearm for purposes of the Gun Control Act, 18 U.S.C. Chapter 44, and the National Firearms Act, 26 U.S.C. Chapter 53.
Per Len Savage:
According to the criteria that ATF applied to figure out the "Upper" is the "receiver" according to the law for an FNC, If the same criteria were applied to the AR-15 / M-16 the "upper" must be the "receiver" not the lower.
Would this impact the NFRTR if the ATF ever does apply the same criteria at some point to the AR-15/M-16?