Ammunition and Black Powder
Ammunition and Black/Smokeless Powder
For eligible persons, neither California nor Federal law impose any limits on purchase or storage of manufactured or reloaded ammunition.
California does place limits on storage of smokeless propellant - 20 pounds - and black powder - 1 pound.
California defines smokeless powder and black powder as explosives
Health and Safety Code 12000
12000. For the purposes of this part, "explosives" means any substance, or combination of substances, the primary or common purpose of which is detonation or rapid combustion, and which is capable of a relatively instantaneous or rapid release of gas and heat, or any substance, the primary purpose of which, when combined with others, is to form a substance capable of a relatively instantaneous or rapid release of gas and heat. "Explosives" includes, but is not limited to, any explosives as defined in Section 841 of Title 18 of the United States Code and published pursuant to Section 555.23 of Title 27 of the Code of Federal Regulations, and any of the following: (a) Dynamite, nitroglycerine, picric acid, lead azide, fulminate of mercury, black powder, smokeless powder, propellant explosives, detonating primers, blasting caps, or commercial boosters.
California requires permits to do things with explosives
Health and Safety Code 12101
12101. (a) No person shall do any one of the following without first having made application for and received a permit in accordance with this section: (1) Manufacture explosives. (2) Sell, furnish, or give away explosives. (3) Receive, store, or possess explosives. (4) Transport explosives. (5) Use explosives. (6) Operate a terminal for handling explosives. (7) Park or leave standing any vehicle carrying explosives, except when parked or left standing in or at a safe stopping place designated as such by the Department of the California Highway Patrol under Division 14 (commencing with Section 31600) of the Vehicle Code. (b) Application for a permit shall be made to the appropriate issuing authority.
Permits do not apply to small quantities, as specified
Health and Safety Code 12102
12102. This chapter does not apply to any possession or use of 20 pounds or less of smokeless powder, or one pound or less of black sporting powder, provided that: (a) Smokeless powder is intended only for hand loading of small arms ammunition of .75 caliber or less. (b) Black sporting powder is intended for loading of small arms or small arms ammunition of .75 caliber or less. (c) All such powder is for private use and not for resale, and, in the case of black sporting powder, there shall be no gift, delivery, or other disposition to another person. (d) The storage, use and handling of such smokeless and black powder conforms to rules, regulations, or ordinances of authorities having jurisdiction for fire prevention and suppression in the area of such storage, use, and handling of such explosives.