Semi-automatic rifles a common denominator in US mass shootings

The mass shootings that regularly stun America often share an important feature: the gunmen used military-style assault rifles designed to kill many people in a very short time.

Such was the case last Sunday in the massacre at a gay nightclub in Orlando, Florida, in which 49 people died and 53 were wounded.

Such high-power weapons -- light, easy to handle and with high-capacity magazines -- were the deadly common denominator in a string of spasms of gun violence:

-- a movie theater in Aurora, Colorado in July 2012 (82 people shot, 12 of them fatalities)

-- Sandy Hook elementary school in Newtown, Connecticut in December 2012 (26 dead, 20 of them small children)

-- the Islamist-linked shooting in December 2015 in San Bernardino, California (36 people shot, 14 of them fatalities)

In the Orlando slaughter by gunman Omar Mateen, many of those who survived the shooting suffered serious wounds because of the gun's high-velocity bullets and their ability to rip away flesh.

President Barack Obama, who met Thursday in Orlando with grieving families, has renewed calls to keep such weapons off the streets -- and out of the hands of violent and unhinged individuals.

"Those who defend the easy accessibility of assault weapons should meet these families and explain why that makes sense," Obama said.

"The motives of this killer may have been different than the mass shooters in Aurora or Newtown," he said in Orlando. "But the instruments of death were so similar."

- Long-gone ban -

Vice President Joe Biden responded Friday to a petition calling for a ban on the assault rifle that was used in Aurora, Newtown and San Bernardino, the AR-15, after it garnered more than 185,000 signatures.

"I want to say this as plainly and clearly as possible: the president and I agree with you," Biden wrote. "Assault weapons and high-capacity magazines should be banned from civilian ownership."

But despite the renewed push for action, no major legal change on assault rifles is expected soon in a country that now counts more guns than people.

In 1994, the US Congress approved a 10-year ban on the manufacture of assault rifles and some high-capacity magazines.

It expired in 2004 and has never been renewed, despite many attempts to get it back into law -- including, poignantly, in the wake of the horrific Sandy Hook school shooting.

In fact, the market for this kind of gun is doing very well. Manufacturers bill them as enhanced sporting rifles, or as the best answer to Americans' zeal for self-defense.

"Even though the gun industry prefers to call semi-automatic assault weapons 'modern sporting rifles', there are no significant differences between them and military assault weapons," the Violence Policy Center said in a report published this week.

High-capacity magazines and other features of the rifles that allow a user to spray bullets at a target have nothing to do with hunting or sport shooting, it added.

Several days after the massacre, Orlando police confirmed that Mateen used a semi-automatic assault rifle called a Sig Sauer MCX, and a Glock pistol. Both were purchased legally.

Manufactured in the state of New Hampshire, the Sig Sauer MCX features a collapsible stock that makes it compact and easy to store, a pistol grip and detachable 30-round magazines.

"These characteristics enhance the gun's lethality by making it easier to shoot, reload, and maneuver in closed spaces such as a dark nightclub," said the Violence Policy Center.

- 30-round magazines -

Like the AR-15, the Sig Sauer MCX owes its existence to military combat, as touted by ads for the manufacturer, which is expanding rapidly in the United States.

Sig Sauer is controlled by German investors but has its headquarters in New England.

"The modular SIG Sauer MCX line was designed in the US after the Department of Defense asked for a compact, quiet rifle able to engage targets out to 300 meters," American Rifleman, the official journal of the National Rifle Association, said in January.

The federal government does not keep track of how many semi-automatic rifles are in circulation, but experts cited by The New York Times estimates the number at several million.

Faced with the strength of opposition from the Republican camp, allied with the powerful gun lobby, most US lawmakers have given up on tough new measures to limit the spread of guns.

The Republican-controlled Congress has steadfastly refused to pass any legislation which it sees as infringing on the constitutional rights of gun owners.

And so the gun control debate in America is often focused on issues like tougher background checks -- not the issue of banning certain weapons outright.

Democrats scored a minor victory Thursday: after a marathon filibuster, they managed to obtain that the Senate examine a bill on preventing people on US terror watchlists from buying guns.

"I truly hope that senators rise to the moment and do the right thing," Obama said in Orlando.

But observers say legislation has little to no chance of passing, with Republicans loathe to hand Obama a victory on such a hot-button issue at the height of an election year.