since you live in California I do beleive you need a pyrotechnic's license-rockets class 3 to launch HPR rockets ....the State of CA license costs $50....You MAY also need to be a member of the NAR or TRA to purchase and possess HPR rocket motors.......
CA is not a NFPA 1127 state so you may only need the PyroTechClass3 license if you limit your rocketry activities to the state of CA....
(6) Pyrotechnic Operator--Rockets Third Class may purchase, transport, store, and launch high power rockets. Experimental high power rocket motors may only be imported, exported, and wholesaled by individuals or companies holding valid import, export, or wholesale licenses. Pyrotechnic Operators-- Third Class may only purchase high powered rocket motors from licensed wholesalers. Operators licensed under subsection (b) are also required to obtain a local permit from the authority having jurisdiction prior to all launches.
§1033. License Required.
No person shall possess, receive, transport, store, or launch any experimental high power rocket motor without first securing a valid license as a Pyrotechnic Operator-- Rockets First, Second, or Third Class from the State Fire Marshal. No person shall sell an experimental high power rocket motor to any person unless the seller possesses a va1id license as a wholesaler or retailer under this chapter.
Authority: Section 12552 Health and Safety Code
Reference: Section 12552 Health and Safety Code
I suggest that you get a copy of the manual: Laws and regulations for the Transportation, Storage and Use of Fireworks in the State of California.... which is online at the CA State Fire Marshall website, along with the application,fees schedule, etc required for a CA Pyrotech license...
You might also want to contact a CA based NAR/TRA club to see what is required to be legal.....
This website decribes what 1 California person went through, step by step:
https://xtratime.net/leup/leup.htm#CARegs
good luck