Found my own answer in 18 USC 922(a) 7 and 8 which states it shall be unlawfull :
(7)
for any person to manufacture or import armor piercing ammunition, except that this paragraph shall not apply to -
(A)
the manufacture or importation of such ammunition for the use of the United States or any department or agency thereof or any State or any department, agency, or political subdivision thereof;
(B)
the manufacture of such ammunition for the purpose of exportation; and
(C)
any manufacture or importation for the purposes of testing or experimentation authorized by the Secretary;
(8)
for any manufacturer or importer to sell or deliver armor piercing ammunition, except that this paragraph shall not apply to -
(A)
the sale or delivery by a manufacturer or importer of such ammunition for use of the United States or any department or agency thereof or any State or any department, agency, or political subdivision thereof;
(B)
the sale or delivery by a manufacturer or importer of such ammunition for the purpose of exportation;
(C)
the sale or delivery by a manufacturer or importer of such ammunition for the purposes of testing or experimenting authorized by the Secretary; and