chargeable to capital account for the taxable year for such expenses shall be reduced by the amount of such excess. (3) Controlled groups In the case of a corporation which is a member of a controlled group of corporations (within the meaning of section 41(f)(5)) or a trade or business which is treated as being under common control with other trades or business (within the meaning of section 41(f)(1)(B)), this subsection shall be applied under rules prescribed by the Secretary similar to the rules applicable under subparagraphs (A) and (B) of section 41(f)(1). . (c) Credit made part of general business credit (1) In general Section 38(b) of such Code is amended by striking plus at the end of paragraph (31), by striking the period at the end of paragraph (32) and inserting , plus , and by adding at the end thereof the following new paragraph: (33) in the case of a taxpayer who is a Federal firearms licensee (as defined in section 45T(d)), the smart gun technology credit determined under section 45T(a). . (2) Deduction for certain unused business credits Subsection (c) of section 196 of such Code is amended by striking and at the end of paragraph (13), by striking the period at the end of paragraph (14) and inserting , and , and by adding after paragraph (8) the following new paragraph: (15) the smart gun technology credit determined under section 45T. . (d) Clerical amendment The table of sections for subpart D of part IV of subchapter A of chapter 1 of such Code is amended by inserting after the item relating to section 45S the following new item: Sec. 45T. Research expenses for smart gun technologies. . (e) Effective date The amendments made by this section shall apply to amounts paid or incurred after December 31, 2018, in taxable years beginning after such date. 3. Firearms tax not to apply to cost of smart gun technology (a) In general Section 4181 of the Internal Revenue Code of 1986 is amended by adding at the end the following new sentence: The price taken into account under the preceding sentence shall