CA AB3

Prohibits licensed firearm dealers from selling or transferring any firearm to persons under 21 years of age, raising the age requirement for all firearms from the previous structure of 18 years for long guns and 21 years for handguns.

Requires applicants to be 21 years of age or older to obtain a unique serial number for any assembled firearm from the Department of Justice.

Raises the minimum age for purchasing ammunition from 18 years to 21 years of age.

Specifies that no state reimbursement is required for local agencies under Article XIII B of the California Constitution because the bill creates or modifies existing crime definitions and penalties.