I can hear the DA now, speaking to the Jury in the murder prosecution case:
"The defendant has the right to defend himself from imminent deadly harm. However, this defendant carries with him on a daily basis 32 bullets for his 9mm pistol. During the altercation, the defendant shot all 16 bullets from his gun, stopped, reloaded his gun, and then shot several more times."
I think that it would not sit well with a Jury in most anti-gun courtrooms in America. It seems that carrying one gun and ammo for it is justifiable. But when you are carrying an arsenal, you may destroy your credibility for "self defense." I think carrying more ammo makes you look like you're looking for a reason to get into a gun fight. Also, in my opinion, if you can't handle a garden variety self-defense problem with 1 magazine, you're in over your head. It's either because
A) you're a really really bad aim, in which case you need more practice
B) you are severely outnumbered and have no business drawing your gun, you should leave the situation immediately
C) you are severly outnumbered and should draw your gun and leave the area immediately