Earlier quoted context omitted.
Because it wouldn't work. You're purposefully trying to work around the intent of things. Judges tend to take ill view of cute things like that. Besides, ok you ban the sale of ammunition. Now are you going to ban reloaders and selling of ammunition components too? How far are you willing to go down that rabbit hole? Noting that it isn't that hard to make ammunition are you going to ban the knowledge of that as well?…
I thought a lot of laws were cute intents to work around the constitution. Any such law would work its way up the legal chain until it got to the supreme court (assuming they chose to take it up the case). As the federal law on armor piercing bullets shows [1] there does not seem to be anything stopping congress passing a law regulating or banning ammunition. Instead of just limiting the ban to armour piercing it cou…
It would be akin to banning cars by banning the sale of wheels. You will be hard pressed to say your intent is to stop people getting run over by stopping wheels from running people over. It is patently obvious your goal is to stop cars from being used. Even if you ban wheels with spikes on them that obviously only ever get used to destroy other cars, that doesn't mean that it is ok to ban all wheels using the same logic.
You'll probably want to ask a lawyer the legal situations behind your proposal. They'll be better able to elaborate. But in talking to some lawyer friends in the past, they note judges are really good at sniffing out attempts to work around the spirit or intent of a law.