The Slingers became vocal and active political advocates for gun law changes after burying their son.

Former Ontario premier Bill Davis, whose 15-year-daughter Cathy was enrolled at Brampton Centennial at the time, was one of the first with real political clout to sound off about seeking legislative change.

Another was Ross Milne. He was the Peel-Dufferin-Simcoe MP at the time. His daughter Jean was in Grade 9 at the school and his son Rob was in Grade 11.

His wife, Lorna, still can’t talk about the shooting without becoming emotional. Moments before John Slinger was killed, he was walking down the hallway with their son Rob.

“They were heading to gym class,” she tearfully recalled. “John went into the washroom along the hallway, Rob went on to the change room to go to the washroom there.”

Word about the shooting reached Ross Milne in the House of Commons during question period.

“I was so stunned for a moment then I sent a note to the Speaker asking could I be recognized. Then I rose and asked if the government would consider implementing stricter gun control rules,” Milne said.

Even then, it was clear opposition to gun control was strong in parts of the House.

Milne would meet with the Slingers in Ottawa, along with other politicians. The Slingers also presented a petition to Solicitor-General Warren Allmand, who now lives in Montreal and still remembers how the shootings stirred gun control debate.

There was considerable public support for stricter laws after the shootings, but the wheels of change grind slowly in Ottawa.

Former Liberal MP Otto Lang served as Minister of Justice and Attorney General in 1975. He was also in the post when legislative changes to Canada’s gun laws were passed in the House of Commons some years later.

“What I remember is that there wasn’t any specific incident or pressure related to any specific incident that led to the development of the moves in regard to more appropriate gun control,” Lang said from his Manitoba home.

The requirement of background checks was something the government was considering before the Brampton shooting, he insisted.

By the time legislative change came, gun advocates had added their voices to the debate.

The powerful lobbying arm of the National Rifle Association (NRA) in the United States reached north of the border to push back against gun control advocates, Milne noted.

“It was a tough go, but we did move the yard sticks a little bit,” he remarked.

“Obviously it wasn’t everything that I wanted or the Slingers wanted or what was needed, but to get it through the House there had to be some consideration for the other side to make sure there was enough votes that something would pass.”