The provisions listed in Section 16590 do not apply to any instrument or device, other than a short-barreled rifle or a short-barreled shotgun, which is sold by, manufactured by, exposed or kept for sale by, possessed by, imported by, or lent by a person who is in the business of selling instruments or devices listed in Section 16590 solely to the entities referred to in Sections 17715 and 17720 when engaging in transactions with those entities.
Ca. Pen. Code § 17725