Sorry, but I am a member of the silent majority of professional airline pilots who are not inclined to take up arms on the job. If ever I were made to do so, I'd quit my airline job.
I believe that armored cockpit doors and bulkheads are sufficient for a secure cockpit,...along with security training, "opened curtains" in the aisles and a new passenger awareness about inflight cockpit security.
Far larger security concerns are about screening checked baggage for explosives, and about securing airport perimeters.