For provisions relating to tax-free sales of firearms and ammunition see:
(a) Section 4221 and 27 CFR 53.131, “Tax-free sales; general rule”.
(b) Section 4223 and 27 CFR 53.132, “Tax-free sale of articles to be used for, or resold for, further manufacture”.
(c) Section 4222 and 27 CFR 53.140, “Registration”.