system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: Preventing mass shootings in the US will be nearly impossible due to the massive numbers of privately held guns.

Given the recent tragedies in El Paso and Dayton, many people offer suggestions on how to prevent future mass shootings. As an American, I agree that there should be more attention and public awareness regarding mental health, gun safety, and best protocols in an active shooter situations.  I even agree with some gun control, specifically banning the use of military grade weapons modified for civilian use (e.g., semiautomatic weapons).

However, the U.S. has the highest rate of gun ownership on the planet.  It’s too easy for any wacko to go to an arms show and buy an AK-47 and then shoot up a random event.  And even if we banned the sale of these types of weapons, there’d be plenty semi-automatic weapons floating around on the black market (I can see an argument that the cost of a semiautomatic weapon would be prohibitive on the black market, but that wouldn’t solve the problem completely).

Many gun control opponents point to the case of Switzerland, which doesn’t suffer the same amount of mass shootings even though almost every household there owns at least one gun. I would counter that by mentioning the general mindset of Swiss society, which engrains the use of weapons for military purposes and hunting.  It seems like many people here in the US think shooting a real gun is like playing Call of Duty.

Edit: After reading through this thread, my argument is now as follows: we should start by banning semiautomatic weapons as in Australia after the Port Arthur massacre.  This won't stop the problem overnight, but it would make purchases of such weapons more expensive and thus mass shootings would be less common.

TL/DR:  I think the USA will never solve the gun problem with so many weapons floating around in private hands.  Even if we banned the sale outright, you’d just have a thriving black market.
gpt
The number of mass shootings in a country correlates with number of guns owned. 

While its true it would take decades to bring gun ownership down to UK levels, for instance, that doesn’t mean making guns more difficult to buy would not prevent deaths.

Look at cigarettes. No one has banned their sale, and high taxation has led, in some states, to a thriving black market. But states with higher taxes on cigarettes have lower rates of smoking, because the cigarettes are harder for people to access.