Increased Background Checks without further bans
Guns don't kill people, people kill people. This is a bit of an exaggeration but bare with me here: if you take an RPG, a grenade, 40mm grenade launcher, heck even an M1A1 Tank, or an ICBM with a nuclear warhead and sit it in front of the grossly ... vast majority of Americans, nothing will happen; it will cause no damage. It's those few mentally unstable individuals that cause the problem by using the weapon for terrorist reasons. The fact is, if you ban the AR15, the guy that is planning on taking it out for killing spree will find it somewhere else or worse, they will have to think harder and end up making something even more dangerous like a pressure cooker bomb.
The solution is vigilance, communication, and verify verify verify. You don't take away the ability of the people to defend themselves from an enemy that is packing more heat than we are. Hey guy that's like "OH come on, we got the police." Yeah, you go ahead and play hide and seek with an assault rifle, shotgun, handgun, explosives, etc. for the average 7 minute response time. Then it's probably going to be even longer while the first responders wait for backup. Then hope the police have the firepower to combat the enemy's: North Hollywood bank shootout 1997, Texas Police Station June, 13th 2015.
You wanna play hide and seek with a semi or fully auto .223, go for it; I'd rather play tag when it comes to my family