For those who do carry such a 'tool' these comments by Massad Ayoob, gun guru, author, instructor and all-around good guy' provides some food for thought. While I have heard/read how few rounds are fired in a civilian gun fight having a spare mag in case of malfunction and/or drop by accident seems like a good idea.
Years ago I took a basic pistol training course with Massad and was very impressed with his depth and breath of knowledge related to firearms.
Years ago I took a basic pistol training course with Massad and was very impressed with his depth and breath of knowledge related to firearms.