How can ' banning ' them effect availability ?
How many millions of firearms are illegal in the United States ? There is literally millions.
Address your point ? Nothing to address Joey. Right now you can obtain a firearm legally. If suddenly there was a nation wide ban on weapons, they would still be obtained, just illegally. The mass shootings and gun related crimes will still continue.
Banning them right now will do nothing. But tomorrow, next week, next month, next year, next decade you will see big reductions.
You aren't going to get them all, but by god, it is better than not doing anything.