Revenue Ruling 58-417

     The Internal Revenue Service has had occasion to consider the
classification status of the new U.S. Army M-14 "rifle" chambered
for the 7.62mm NATO cartridge, in the light of the provisions of
the National Firearms Act (Chapter 53 of the Internal Revenue Code
of 1954).  Held, (1) that since the M-14 "rifle" operates either
fully automatically or semi-automatically on a selective basis, it
is in basic design and function a "machine gun" as defined in
Section 5848(2) of the Internal Revenue Code of 1954 and,
accordingly subject to the provisions of the National Firearms Act,
and (2) that the substitution of a selector shaft lock, in lieu of
a selector lever assembly, on the M-14 "rifle" is of temporary
nature and, therefore, does not materially alter the classification
thereof for purposes of the National Firearms Act.