Debate: Why own a .223-caliber semiautomatic rifle like the one used in Newtown, Conn.?

This post has been updated.

The victims of the Newtown, Conn., tragedy were all shot with a Bushmaster .223-caliber semiautomatic rifle — a rifle that is legal to own in Pennsylvania.

The gun is a civilian version of the military's M-16 and often seen at marksmanship competitions. It's similar to the weapon used in the 2002 sniper killings in the Washington, D.C., area and in a recent shopping mall shooting in Oregon.

Versions of the AR-15 were outlawed in the United States under the 1994 assault weapons ban. That law expired in 2004, and Congress, in a nod to the political clout of the gun-rights lobby, did not renew it.

But, whether it's legal or not, does anyone really need to own such a high-powered gun?

Bob Kostaras, owner of Classic Pistol in Southampton, Bucks County, and Shira Goodman, executive director of CeaseFirePA, debate that question:

Kostaras: "We have an indoor target range. We have people here all day shooting them. People enjoy it. They're not prepping for end of the world, they just enjoy shooting them. For some, it's a social thing, it's a sport. Any weapon, a baseball bat, a car with a drunk driver behind the wheel, is much more dangerous and much more liable to kill somebody. Unfortunately, this person was mentally unstable and had access to the firearm that should have been kept out of his reach."

Goodman: "Maybe this isn't something that everybody should just be able to have access to.... Since there is access to them, that adds to the stream of guns that can then become illegal guns. Types of weapons that are available is a problem, but I believe it's only part of the problem, because certainly we've seen much devastation with handguns or other kinds of rifles that people might have for the more legitimate hunting purposes or personal-protection purposes. I don't think it's just a matter of types of weaponry available.… Because citizenry has access to that type of weapon and it can be sold easily, it makes it more dangerous for when those guns fall into the wrong hands."

Kostaras: "You don't find your normal, responsible people getting in trouble for owning guns. They're not dangerous in the right hands. They are in the wrong hands, but so is a car.... Criminals don't go to the gun store and buy the gun. They're not following the laws you and I follow, so they're not bound by them.... This is a terrible tragedy."

Goodman: "The trouble with the original [assault-weapons] ban from 1994 to 2004 was the way the weaponry was defined, so it was easy to make modifications to certain things, then have weapons that may have complied with the letter of the law, but not exactly the spirit. I think we need to look at what it is we're actually trying to prevent.... It's about making sure that law-abiding gun owners are responsible for securing their weapons."