Accurate bullet placement is much more important than how many rounds you put down range. That is part of the problem with the innocent people being shot during some of these inner city gang shooting. An untrained person will just fire away, hoping to hit their target, but not caring who else gets shot!
I have no idea of your situation, but for personal self defense it is very unlikely that a barrage of gunfire is needed. Training, accuracy, and practice are much more valuable than scores of rounds carried for SD.
Cheapshooter's rules of gun ownership #1: NEVER SELL OR TRADE ANYTHING!