One individual with a rifle attempted to execute 12 police officers. He succeeded in about half the ones he shot. You must live in la la land if you think the police are going to go in and take guns away from gangs. That, and you have absolutely no clue about the 4th Amendment, aside from the practical side of your suggestion.
You also know nothing of gun laws on the books. Carrying a concealed weapon without a permit is grounds for seizure and is used regularly. The problem is, the police are already being charged for stopping young black men under the areas of “Walking while Black” or “Driving while Black”. and just how do you propose that the police find these concealed weapons, other than searches simply based on race?
Then you need to deal with the ACLU, which has vigorously fought for the rights of insane people; it is next best impossible to deal with people like that shooter. And taking away guns from literally millions of people in order to try to take it away from the criminally insane is…
Wait for this…
Insane.
No one wants a Sandy Hook. In China, one guy went into a school and killed kids. With a knife. The problem of Sandy Hook, and Colorado is not guns; it is our inability to deal with people on the irrational edge of society.
and then there was Oklahoma; so now because of Sandy Hook, Oklahoma, and your rationale, we should ban oil and fertilizer.
Okay, problem solved. Not.