Mandate a point-of-purchase federal tax of $500 for every handgun, $1,000 for every rifle, and additonally add $500 for any firearm capable of automatic fire.
Mandate a similar, annual federal tax for every firearm, similar to a vehicle registration tax. No discount for multiple firearms, in fact, double taxes for multiple firearm ownership.
Require firearm owners to present a weapon in order to purchase ammunition.
Confiscate and destroy unregistered weapons and impose mandatory jail time and fines for anyone found to have an unregistered firearm.