Expensive? A few thousand dollars? Not really, anyone can save up that much money working odd jobs, especially if they see it as their last investment on earth.
Instead of a ban, why don’t we tax the hell out of them, raise the price on high-powered weaponry to $50,000 or more? You know, the cost of a few days in the hospital? That would be a uniquely American solution to this problem.
There’s a right to arms, but not a right to affordable arms!