If you are a prohibited person, possessing, acquiring, or seeking to acquire a firearm is already illegal. It is already illegal to knowingly provide a firearm to a prohibited person. The majority (as in effectively all) of firearm transfers to prohibited persons are done by friends, family, and criminal associates aware of their prohibited status.

So, how do you propose to stop people who are knowingly violating the law now, from violating another law you might pass? How, -exactly-, do you propose to enforce a law banning an activity which can only be detected, much less proven in court, to have occurred if it happens to do so in the presence of law enforcement knowledgeable of the status of both parties?