The trial court erred in granting the defendant gun shop summary adjudication of plaintiff gun shot victim’s negligence per se claim based on sale of the gun to an 18-year-old who did not possess a valid, unexpired hunting license. See Pen. Code 27510.) Though “valid, unexpired” was ambiguous as to whether it included a valid license before its effective date, the later enactment of Pen. Code 16685 made it clear that a gun may not be sold to one under 21 until the hunting license becomes effective. Here, defendant sold the gun after issuance but before the effective date of the hunting license and so violated the statute, allowing plaintiff to pursue a negligence per se claim.