A trio of Ohio Republicans have bucked their National Rifle Association backing to lobby for tighter gun control — including a ban on sales of assault rifles — in the wake of Sunday’s mass shooting in Dayton.

Rep. Mike Turner, whom the NRA endorsed with an “A” rating ahead of the 2018 midterm elections, said Tuesday that he now backs legislation that “prevents the sale of military-style weapons to civilians, a magazine limit, and red flag legislation.”

“I strongly support the Second Amendment, but we must prevent mentally unstable people from terrorizing our communities with military-style weapons,” said Turner in a statement.

“The carnage these military-style weapons are able to produce when available to the wrong people is intolerable.”

Turner’s 180-degree turn on assault rifles came after he revealed that his daughter and a family friend were in downtown Dayton’s Oregon District early Sunday when Connor Betts, 24, opened fire with an AR-15-style rifle, killing nine people before he was gunned down by cops.

“As a result of the police’s actions, my daughter and hundreds of others who were in the Oregon District last night are alive,” Turner said Sunday. “This is an unbelievable amount of evil that we cannot comprehend.”

Gov. Mike DeWine and Lt. Gov. Jon Husted, both of whom were endorsed alongside Turner by the NRA, have also come around on steps toward gun control.

DeWine — who was besieged by mourners’ calls of “Do something!” during a vigil in Dayton — also came out Tuesday in favor of background checks for most gun purchases in his state, as well as restricting firearms access to people perceived as unstable.

“We know there’s going to be some violence; it’s the world we live in,” said DeWine. “But I can tell you this: If we do these things, it will matter. If we do these things, it will make us safer.”

Husted, speaking Wednesday on CNN’s “New Day,” said he hopes President Trump’s visit to Dayton will open Trump’s eyes to the idea that change is needed.

“When he visits the site and sees the bullet holes and the bloodstains, I think that has an effect on you as a human being,” said Husted. “I think the president needs to see that and search his heart and his mind to respond to what the people of Dayton will be asking him to do.”

With Post wires