We’ve seen some thought-provoking opinion pieces lately about gun control sparked by last month’s Las Vegas tragedy and now the shooting massacre closer to home in Texas. In one piece, Alexandra Petri of the Washington Post stressed that the time to have a national dialogue about gun control is now, not later.

Another by Leah Libresco of the data journalism site FiveThirtyEight dealt with what details this dialogue should focus on. It’s not the usual proposals for increased gun control: Libresco did something rare. She looked at real gun-violence data, which showed those proposals to be ineffectual.

Like some liberals, Libresco went into her data research expecting it to show the need for things like bans of assault-style weapons and clip-size limits. But her data analysis surprised her. She found those things don’t really work.

I’ve looked at a subset of mass-shooting incidents using the database posted at MotherJones.com and found two things that would probably help. I only looked at mass shootings; Libresco looked at that plus domestic violence and gang violence. But we reached similar conclusions: The usual proposals, as many gun enthusiasts often insist, simply won’t work.

Two things jumped off the page when I put the data onto a spreadsheet and color-coded the cells. First and foremost: Nearly every incident of mass shooting involved a person with mental issues buying guns legally, precisely because no judge had ever ruled him not sane. Solution: Ensure law enforcement agencies and the courts actually follow through on such cases and that any convictions and commitments are properly entered into existing databases. In short, fix that leak and much of the problem of shooting massacres goes away.

Second, nearly every incident involved a sitting-duck target crowd in an undefended or improperly defended, gun-free zone. These not only invite crazy shooters such as in Las Vegas and now Sutherland Springs, they also invite terrorist attacks such as in San Bernardino. Solution: Defend such zones better.

There are plenty of very good reasons to have gun-free zones, such as education venues so that ideas can be exchanged without fear or intimidation. Campus-carry is the wrong idea because it actually inhibits those discussions.

We have known since 19th-century frontier-town experiences what constitutes an adequately defended gun-free zone. Turns out that our dusty American ancestors knew what works quite well. A duly qualified and adequately armed peace officer needs to be able to reach anywhere in a gun-free zone within 60 seconds or so.

Towns then were small. When they grew, this didn’t work as well. Today it means you have a guard station or stations dispersed about your gun-free zones. And concealed-carry training is not peace-officer training. Safety and effectiveness are more important than convenience or cost. Simple as that.

As for the “crazy persons leak,” I propose that persons selling guns be enabled to flag customers who appear “not right” mentally to local law enforcement who can conduct appropriate scrutiny. Law enforcement then does a real background check, asking real people real questions — not just some online records search for court judgments. That might have stopped the Las Vegas shooter and many others (though maybe not the Sandy Hook shooter, who murdered his mother to get her guns illegally).

One other thing has surfaced since the Las Vegas tragedy, lest we forget: bump stocks and other devices that effectively make a machine gun out of a semi-automatic weapon. We prohibited civilian possession of machine guns in 1934 because of the horrifying death toll from organized crime figures using them in our streets. That solution worked fairly well, precisely because the much higher rate of sustained fire with a machine gun is so much more deadly.

That law was updated in 1964, then again in 1986. The only machine guns permissible under the current version are grandfathered items from before 1986 — and then only with an exhaustive background check. This law prohibits changing the loading mechanisms of semi-automatic weapons to full-automatic operation.

And there is a leak: Bump stocks and trigger cranks do not modify the loading mechanisms and so are considered legal under federal law as it is, but they do increase the rate of fire to machine-gun speeds, which is precisely the danger we have restricted since 1934. That leak needs to be fixed — and our lawmakers need to quit balking at ensuring this is promptly addressed.

For the record, we tried an assault-styled weapons ban from 1994 to 2004. It didn’t help. Calling a semi-automatic AR-15 an assault weapon just because it looks like the fully automatic M-16 military machine gun turned out to be rather stupid and ineffective. What’s important is rate of fire, not cosmetics.

Clip-size limits are of little to no effectiveness because it takes only a couple of seconds for someone familiar with the weapon to change clips. Restricting “silencers” is also of little use because most of these are noise reducers only, not real silencers. And the cities with the most restrictive gun laws are also the cities with the highest gun-death rates, so that doesn’t work either.

Fix the “crazy person” leak in the background-check process and many shooting massacres will go away. Fix the gun-free zone problem and reduce the risk of terrorist attacks as well. Restrict rate of fire to only semi-automatic levels, not machine-gun speeds (meaning three shots per second or less). The rest in the gun-control manual is so much smoke and mirrors.

Gary W. Johnson is a former cutting-edge aerospace defense engineer who lives in McGregor.