I think that depends on how you normally train as we "fight like we train".
If you normally practice with hi-capacity magazines and run shooting drills with multiple bursts into your target(s) before you reassess your situation/surroundings for additional threat(s), you may easily deplete your 8 rounds and end up with an empty weapon too light to be used as a rock if there is no spare magazine.
Here in California, we have been restricted to 10 rounds (although, a lot of pre-ban hi-cap magazines do exist) and many of us have revised our training practice to make best use of the reduced round count. I for one believe in the notion that you use lethal force when absolutely necessary, but once you start using lethal force, you do not stop using it unless you are absolutely clear the immediate threat to your life is gone (dead/not moving) or your magazine is empty, whichever comes first - for obvious legal reasons. With the 10 round magazine limit, use of spare magazine(s) is a must for us (and for additional reasons mentioned below). My "legally correct" defensive use of my firearm drill goes like this - Shoot until empty. So when I am asked, "Sir, why did you shoot the attacker 10 times?" I can answer by saying, "Sir, because I only had 10 rounds in the magazine. As I was reaching for my spare magazine to reload, in my state of fear-for-my-life, I saw that the attacker was no longer making threatening motion. So after I finished reloading my pistol, I called 911."
Do not believe what you see in the movies. one or two bullets out of any short barrel pistol into center-of-mass WILL NOT drop a decent sized attacker determined to kill you/harm you like you see in the movie scenes. Your attacker WILL not die the second the bullets hit unless those projectiles cause fatal head injuries.
I for one recommend you carry the maximum capacity your magazine will allow and carry at least one more spare, just in case there is:
- More than one attacker threating your life determined to attack you after seeing his/her partner get shot
- Your shots "somehow" missed all vital/critical organs and the attacker is still a threat to your life
- The attacker was wearing body armor/recovered and still a threat to your life (and you regroup and shoot the hip/pelvis area with follow-up head shot)
- Your pistol experiences malfunction that requires removal of magazine (it is faster/better to do a tactical reload than reinsert the potentially malfunctioning magazine)
These are just a few reasons.
