Cal. Revenue and Taxation Code - RTC § 36021. Section 36021.
(a)
There are exempted from the tax imposed by this part, the gross receipts from the retail sale of any firearm, firearm precursor part, or ammunition to any active or retired peace officer or any law enforcement agency employing that peace officer.
(b)
There are exempted from the tax imposed by this part, the gross receipts from the retail sale of any firearm, firearm precursor part, or ammunition by any licensed firearms dealer, firearms manufacturer, or ammunition vendor in any quarterly period in which the total gross receipts from the retail sales of firearms, firearm precursor parts, or ammunition by that licensed firearms dealer, firearms manufacturer, or
ammunition vendor is less than five thousand dollars ($5,000).