The National Rifle Association is firing allegations at U.S. Rep. Patrick Murphy, saying the Democratic Senate hopeful wants to take away voters’ guns.

The gun rights group’s lobbying arm, the Institute for Legislative Action, attacked Murphy in a mailer we received on Oct. 4, 2016. The flier listed several reasons why Murphy is against guns.

"Murphy supports a gun ban on commonly owned semi-automatic firearms used for hunting, recreational shooting and self defense," one of the items read.

That sounds like Murphy, now running against incumbent Marco Rubio for U.S. Senate, wants to make it illegal to own a wide range of weapons, so we zeroed in on that statement.

‘Military-style weapons of war’

Murphy has been an advocate of stricter gun control, especially in the wake of the June 12, 2016, mass shooting at Pulse nightclub in Orlando. Omar Mateen killed 49 people and wounded 53 others using a semi-automatic rifle and handgun.

Murphy called for keeping "assault weapons out of the hands of dangerous people."

In an August 2016 candidate survey, Murphy told the Tampa Bay Times he does not believe "that civilians need access to military-style assault weapons."

In September, he told the Orlando Sentinel he agreed with the families of the Pulse victims who wanted Congress to ban weapons like the rifle Mateen used. Murphy said the government should "keep military-style weapons of war out of our communities and out of the hands of criminals and terrorists."

Murphy’s campaign did not provide any specifics about what types of guns, other than to call them "military-style assault rifles" and "dangerous weapons of war."

Technically there’s no true definition of what makes a particular rifle an "assault weapon." There’s no clear, legal interpretation of any of the descriptions Murphy and other gun control advocates are using, giving the NRA wide berth in its attack.

Put simply, the term "semi-automatic" refers to any firearm designed to fire one bullet with one trigger squeeze, then automatically reload the chamber and be ready to fire again.

This is different from an automatic weapon, in which squeezing the trigger once fires multiple times until the shooter lets go. Automatic weapons sales have been restricted in the United States since 1934. Regulations put in place in 1986 made it much more difficult for civilian buyers to get an automatic weapon.

Experts told us that while legislators have struggled for decades to find a universal term that fits the mold, in general that means so-called black rifles that look like a soldier’s weapon.

These include rifles that have pistol grips, high-capacity magazines, bayonet lugs to fix edged weapons, flash suppressors at the end of the barrel and so forth.

The NRA-ILA told us Murphy and others usually are referring to rifles similar to the AR-15, which is a derivative of a rifle first developed by gunmaker ArmaLite in the 1950s. (The AR refers to ArmaLite rifle, and does not stand for "assault rifle.")

There are somewhere between 6 million and 10 million of these semi-automatic rifles in circulation in the United States. The NRA routinely refers to this style of semi-automatic weapon — used in shootings in Aurora, Colo.; Roseburg, Ore.; San Bernadino, Calif.; and Newtown, Conn. — as a "modern sporting rifle."

One of Mateen’s weapons in the Pulse shooting, a Sig Sauer MCX, is similar in style to an AR-15 but not the same design.

Internally, however, the consumer versions of these rifles basically work the same as any other semi-automatic rifle. Cartridges are fed from magazines and are fired one at a time with each trigger pull. They are used for self-defense and recreational shooting, just as the NRA said. About half of all guns are semi-automatic.

Handguns are far more prevalent in crimes. The 2007 Virginia Tech shootings, for example, were committed with two semi-automatic handguns, a Glock 19 and Walther P22, she said. Mateen also used a Glock 17 pistol.

Tomislav Kovandzic, a University of Texas at Dallas professor who teaches classes on research methods and gun control, said many lawmakers resort to focusing on specific makes and models that usually are both semi-automatic and considered military in appearance. That’s what the 1994-2004 federal assault weapons ban did. Kovandzic said in the research he’s seen, these types of "assault weapons" are used in less than 2 percent of gun crimes.

Of course, the NRA words the claim in such a way that there could be some confusion about Murphy’s wishes. While Murphy is focusing on rifles that are arguably only cosmetically different, his intention is a bit obscured by the mailer.

"He may want to ban some semi-automatic weapons," UCLA constitutional law professor Adam Winkler said, "but he doesn’t want to ban all semi-automatic weapons."

Our ruling

The NRA-ILA said, "Murphy supports a gun ban on commonly owned semi-automatic firearms used for hunting, recreational shooting and self defense."

Murphy has called for a ban on ill-defined "military-style weapons of war" and "assault weapons." His campaign didn’t specify further which guns, but these political terms usually refer to rifles used in some mass shootings with mostly cosmetic differences from other semi-automatic rifles.

These rifles, often based on the AR-15, are used by owners in the way the NRA describes. But the mailer could be construed as saying Murphy wants to take away most, if not all, semi-automatic firearms, which Murphy denies.

Their statement is slightly off the mark, so we rate it Mostly True.