I'm all for better background checks, but if you think banning guns is going to solve anything, you're incorrect. Both the Walmart in El Paso and the bar in Dayton were gun-free zones. If we use the outright banning side's own logic, they should be against anyone owning knives after the attack that left 4 dead and 2 or more wounded in California.
Everyone screams about mass shootings, but that's only because they get media attention, and even then, it's only when it happens during daylight. Gang shootings rarely get media attention outside of their local cities. If I'm remembering correctly, 67% of all gun deaths in the US are suicides. The odds of you being shot in a mass shooting vs the odds of you committing suicide are essentially the same as the odds of you dying in a plane crash vs the odds of you dying in a car crash. One is scarier than the other, but far less likely to happen.
And as
@SBaby said, if you outlaw firearms, which are far more valuable than most drugs, the gangs and the cartels will start mass-producing them, and they'll hand them out to anybody who wants them.
As for the "military-grade" and "tons of ammunition" being illegal argument, shooters will just start working around them by carrying multiple guns so they can drop one as soon as it runs out of bullets and start shooting again without even having to reload.
I don't own a gun at the moment, but I have considered getting one for self-defense.