" but the short term period in which the bad guys are armed and the good guys largely not would likely be rather painful."
Try *extremely* painful. I don't own a gun, but until we can get guns out of criminal hands at a much higher level, I believe every law abiding, mentally sane citizen fo legal age should have the privilege to own one if they choose. I don't believe in forcing them upon people but I also don't believe in stripping them away completely. There is a middle ground and many on both sides refuse to see this.
First, toughen up the criminal violations. Criminal caught with an illegal weapon? Life without parole. Use a gun in the commission of a crime where no one gets killed? Live without parole. Someone gets killed? Death penalty. Make it so the penalty is so extreme that no semi sane criminal will *want* to use a gun or get caught illegally owning a gun.
Second, toughen up the difficulty for getting a gun. Require training courses for any gun classification (classification being revolver, semi-auto handgun, semi-auto rifle, bolt-action rifle like a hunting or sniper-style rifle, shotgun). Doesn't matter if they are conceal carrying or not. The would be buyer must take a course in firearms safety and prove proficiency in a gun classification. You can't drive a semi, bus, limo, or motorcycle without just a plain ol' driver's license. You need an endorsement, so let's make that happen with gun licenses. Background checks should be more inclusive. Currently a number of states don't send their mental history records to the federal database. Fine the states millions per day until they start. They'll quickly get off their asses and start sending the info when they not only loose federal funds, but start getting find for violating federal law.
Finally, start recording all *ammo* purchases. They can only be to people who hold valid gun licenses for that type of ammo. Yes, I know some munitions cross over, but not much does. And where it does, they still have to have the valid endorsement for one of the classification of firearms that uses that ammo. And make the license and endorsement have to be renewed with a refresher course periodically. It won't force them to return the guns they own, but it will force them to renew to get ammunition for the weapon.
Lastly, and it can be done with the previous put in place, limit the amount of ammunition purchased in a given time frame. We do it with drugs that contain pseudoephedrine - we can do it with munitions *if* we have the licensing I laid out above in place.