Exactly.People don't "need" 95 percent of what they have.
Being able to have more than we need is part of the pursuit of happiness.
But..........I DO need 30 round magazines in case I have to fend off multiple attackers.
Ask them if they think the police need 30 rounds.........if they say yes.........tell them you need to fight off the same bad guys the police are fighting. Hell, the police may even be on their way to my house with their 30 rounds to fight multiple bad guys in MY house.