After extensive analysis of the laws and regulations, the Bureau has determined that the only legal pathway to add a caliber to an existing firearms permit under current Bureau law and regulations is for the permit holder to complete the course of training in the carrying and use of a firearm required to obtain an initial firearm permit, as prescribed by, Title 16, Division 7, Section 635 of the California Code of Regulations. Specifically: Completion of at least 8 hours of classroom instruction on the carrying and use of a firearm, Passing a Bureau-approved written firearm exam with a minimum score of 85%, and Discharging 50 rounds a minimum of two (2) times, one (1) round for practice and one (1) round for score.