I can throw a rock and hit my target much further than 21 feet.
Can you do that while that target is throwing rocks back at you? What if they've got a head start?
Do the stats indicate how many rounds are fired in the vast majority of gun fights, how many of those rounds fired hit their target or how many hits on target it typically takes to end the situation?
Not criticizing your choice, I've walked out of my front door many a day with nothing but a J frame .357. Just suggesting that distance doesn't tell the whole story or even the most important part of the story.