Calif. Civil Code section 1714(a)
Everyone is responsible, not only for the result of his
or her willful acts, but also for an injury occasioned to another by
his or her want of ordinary care or skill in the management of his or
her property or person, except so far as the latter has, willfully
or by want of ordinary care, brought the injury upon himself or
herself. The design, distribution, or marketing of firearms and
ammunition is not exempt from the duty to use ordinary care and skill
that is required by this section. The extent of liability in these
cases is defined by the Title on Compensatory Relief.