Reply #3: Try enfocement and punishment...

[MrSandman]

Under federal law felons, drug dealers and other specified individuals can face up to life in prison for illegally possessing a gun or ammunition. Enforcement helps reduce gun violence in several ways:

It reinforces the message that the community will not tolerate gun violence.
It removes serious violent offenders from the streets and from our neighborhoods.
It increases the risk faced by potential offenders.

http://www.hardtimeforguncrime.org/didyouknow.html

Or let violent criminals try their hand at retail sales.