The fallacy of this regulation is that criminals go to your friendly firearms retailer, get their NICs check done and wait three days. The latter two don't work, so why would the price at the store? Besides, if it costs another $400, Slimey Joe will just mug another guy at the ATM before he heads down to Guns R Us for his perfectly legal, retail-price-control-purchased sidearm.
To recite what is all but boilerplate: Any gun regulation is redundant and meaningless to the reduction of crime. Enforce what we have already e.g. don't kill anyone. The roots of violence are a societal problem that is in no way addressed by limiting the devices employed as evidenced by the wildly differing but overwhelmingly unproductive results in gun-restrictive cities, states and nations.