Gun stocks are rallying (as they usually do after a mass shooting)

Fred Imbert | CNBC

Show Caption Hide Caption Why AR-15-style rifles are so common in mass shootings AR-15-style rifles have been used in multiple mass shootings in recent years, including the high school shooting in Parkland, Florida. See why.

Shares of gun manufacturers rose in the premarket Thursday, continuing rallies in the wake of the tragic shooting at a high school in Florida.

Sturm Ruger and Smith & Wesson's parent company, American Outdoor Brands, rose 2.8% and 2.4%, respectively, before the bell.

The Broward County Sheriff's Office said 17 people were gunned down Wednesday at Marjory Stoneman Douglas High School in Parkland, Fla. The shooter, identified as 19-year-old former student Nikolas Cruz, was booked on 17 counts of premeditated murder Thursday. He allegedly used an AR-15 assault rifle in the rampage.

More: President Trump to address nation at 11 a.m. on Florida school shooting

More: Florida school shooting suspect charged with premeditated murder

More: Survivor: I will never be OK until we stop school shootings

Shares of Sturm Ruger and American Outdoor Brands rallied Wednesday afternoon as news of the shooting broke. The stocks closed 2.8% and 5.6% higher, respectively.

Fear of tougher gun laws after deadly shootings may drive people to stockpile weapons. History shows that Sturm Ruger and American Outdoor Brands rise 1.6% and 2.2%, respectively, five days after a mass shooting, a CNBC study using Kensho found. The study looked at their performance following mass shootings dating back five years.

Several U.S. lawmakers called for tougher gun control laws in the wake of the shooting. Sen. Chris Murphy, D-Conn., tweeted Wednesday night: "Don't tell me tomorrow isn't the appropriate time to debate gun violence. If you're a political leader doing nothing about this slaughter, you're an accomplice."

Don't tell me tomorrow isn't the appropriate time to debate gun violence. If you're a political leader doing nothing about this slaughter, you're an accomplice. — Chris Murphy (@ChrisMurphyCT) February 15, 2018

Rep. Eliot Engel, D-N.Y., said: "Another terrible school shooting, this time in Florida. At least 18 other school shootings have already happened this year. My heart breaks for those children and their parents. How many more victims until we decide gun violence is a national problem?"

Another terrible school shooting, this time in Florida. At least 18 other school shootings have already happened this year. My heart breaks for those children and their parents. How many more victims until we decide gun violence is a national problem? https://t.co/QbLjIbTQEO — Eliot Engel (@RepEliotEngel) February 14, 2018

Rep. Lloyd Doggett, D-Texas, also tweeted: "Another day, another shooting, indeed, multiple shootings today, while Congress sits in the grip of the NRA, incapable of making the slightest gesture toward reasonable gun safety."

Another day, another shooting, indeed, multiple shootings today, while Congress sits in the grip of the NRA, incapable of making the slightest gesture toward reasonable gun safety. — Lloyd Doggett (@RepLloydDoggett) February 14, 2018

However, new gun-control laws are unlikely to be passed anytime soon. Both the Senate and the House are controlled by the Republican Party, and many of their members receive contributions from the National Rifle Association, which heavily opposes gun regulation.

President Donald Trump has resisted calls for greater gun control measures after previous mass shootings. He tweeted condolences on Wednesday.

My prayers and condolences to the families of the victims of the terrible Florida shooting. No child, teacher or anyone else should ever feel unsafe in an American school. — Donald J. Trump (@realDonaldTrump) February 14, 2018

A senior administration official told NBC News there's a "strong chance" Trump will publicly address the Florida school shooting on Thursday.

Disclosure: NBCUniversal, parent of CNBC, is a minority investor in Kensho.

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