Tea party-backed Sen. Ron Johnson (R-WI) says that the right to own high-capacity ammunitions magazines like the 100-round drum that was used to kill at least a dozen people in Colorado last week is a "basic freedom" that is protected by the U.S. Constitution.

Fox News host Chris Wallace on Sunday asked Johnson why people needed military-grade weapons like the AR-15 semi-automatic rifle and large ammunition clips used by the shooter in Aurora, Colorado where at least 12 were killed and 58 were wounded.

"The left always uses the term 'assault rifle,' and they're really talking about semi-automatic weapons that are used in hunting," Johnson explained. "That's what happens in Wisconsin. These are rifles that are used in hunting. Just the fact of the matter is this is really not an issue of guns. This is about sick people doing things you simply can't prevent. It's really an issue of freedom."

"Does something that would limit magazines that can carry 100 rounds, would that infringe on the constitutional right?" Wallace wondered.

"I believe so," Johnson insisted. "There are magazines -- 30-round magazines -- that are just common all over the place. You simply can't keep these weapons out of the hands of sick, demented individuals that want to do harm."

"I would be very surprised if hunters in your state hunted with a 100-round ammunition feeding device," Sen. Diane Feinstein (D-CA) disagreed. "In the bill I did, we exempted 375 rifles and shotguns by name so that no weapon used for hunting was effected at all. It's just the military-style assault weapons."

"But the result of that ban, it didn't solve any problems," Johnson insisted. "I look at the statistics and say it has no measurable effect. You can actually argue that it made matters worse. But I don't want to get into statistics. We are talking about basic freedoms."

In fact, Johnson would have liked to have seen more people armed in that Aurora theater.

"It's certainly one of the rationales behind concealed carry, where criminals actually had to be a little concerned before they commit a criminal act that maybe somebody could stop them," Johnson told Wallace. "And I think that is the truth, that if somebody -- a responsible individual -- had been carrying a weapon that maybe, maybe it could have prevented some of those deaths, some of those injuries. I mean, that's just the truth."

"And maybe you could have had a fire fight and killed many more people," Feinstein pointed out.

Watch this video from the Fox News' Fox News Sunday, broadcast July 22, 2012.