From [Title 18 United States Code (U.S.C.), Chapter 44, S 921(a)(3)] and [26 U.S.C., Chapter 53, S 5845]
Just a bit of legal mumbo jumbo but I am definitely in the clear it would seem.
(3) The term "firearm" means (A) any weapon (including a starter
gun) which will or is designed to or may readily be converted to
expel a projectile by the action of an explosive; (B) the frame or
receiver of any such weapon; (C) any firearm muffler or firearm
silencer; or (D) any destructive device. Such term does not include
an antique firearm.
(4) The term "destructive device" means -
(A) any explosive, incendiary, or poison gas -
(i) bomb,
(ii) grenade,
(iii) rocket having a propellant charge of more than four
ounces,
(iv) missile having an explosive or incendiary charge of more
than one-quarter ounce,
(v) mine, or
(vi) device similar to any of the devices described in the
preceding clauses;
(B) any type of weapon (other than a shotgun or a shotgun shell
which the Attorney General finds is generally recognized as
particularly suitable for sporting purposes) by whatever name
known which will, or which may be readily converted to, expel a
projectile by the action of an explosive or other propellant, and
which has any barrel with a bore of more than one-half inch in
diameter; and
(C) any combination of parts either designed or intended for
use in converting any device into any destructive device
described in subparagraph (A) or (B) and from which a destructive
device may be readily assembled.
The term "destructive device" shall not include any device which is
neither designed nor redesigned for use as a weapon; any device,
although originally designed for use as a weapon, which is
redesigned for use as a signaling, pyrotechnic, line throwing,
safety, or similar device; surplus ordnance sold, loaned, or given
by the Secretary of the Army pursuant to the provisions of section
4684(2), 4685, or 4686 of title 10; or any other device which the
Attorney General finds is not likely to be used as a weapon, is an
antique, or is a rifle which the owner intends to use solely for
sporting, recreational or cultural purposes.
The most interesting part is the underlined section, apparently the secretary of the army can loan out ordinance????