Not an assault rifle but. SBR short barreled rifle a bit of leftovers from FDR. NFA 1934
Definition of an SBR and how you can legally own one. This is a FEDERAL REQUIREMENT. Doesn’t have anything to do with California.
In the United States, it is a federal felony to possess an SBR without paying a $200 tax to the BATFE. BATFE notification is required when transporting an SBR across state lines; this is accomplished by filing Form 5320.20 in advance of the travel date. One must be cautious not to take an SBR into a state where the SBR is prohibited. One can take an SBR through a state where the weapon is prohibited when on a direct route and have prior approval from the BATFE with a Form 5320.20. One must be careful not to take an SBR into international waters, as there is a proper procedure to return with the SBR to the United States.[3]
Purchasing a short-barreled rifle is accomplished by filing a BATFE Form 4, Application for Tax Paid Transfer and Registration of a Firearm, and paying a $200 tax. A short-barreled rifle must be transferred by a Class 3 or a Class 2 SOT dealer. When an individual wishes to build a short-barreled rifle, he or she must beforehand submit a completed BATFE Form 1, Application to Make and Register a Firearm, along with $200 for payment
I didn’t mention “assault rifle”. Was your post intended for someone else?