Appearing on "60 Minutes" Sunday night, family members of the victims killed in the Newtown, Connecticut massacre said that limiting the sales of high-capacity magazines is "crucial" to any effort that hopes to prevent another similar event.

The families are members of the group Sandy Hook Promise, which launched a petition urging lawmakers to honor the victims by committing to passing gun control legislation.

Bill Sherlach, whose wife lost her life trying to stop the shooter, said that limiting magazine size is particular "critical" because "you can have a million bullets, but if you have to put them in one at a time, the ability to do any kind of real damage is significantly reduced."

The shooter in Newtown, Adam Lanza, walked into the Sandy Hook elementary school armed with a semi-automatic Bushmaster AR-15 and 10 extended magazines with 30 bullets each, firing a total of 155 bullets in just less than 5 minutes -- a rate of roughly two bullets per second. A shocking toll resulted: 26 people dead, including 20 children.

There is one very clear instance of a mass killer being stopped while reloading: the rampage in Tucson, Arizona, which came to an end when Jared Loughner was forced to pause and reload after emptying a 33-round magazine in about 19 seconds. A total of 19 people were shot, including the-Rep. Gabby Giffords (D-AZ), and six people died.

Even in the shooting in Newtown, one of Lanza's reloads is said to have taken longer than the others, which Sherlach pointed out "allowed 11 kids to get out of the classroom."

"It's just a simple arithmetic," he said. "If you have to change magazines 15 times instead of five times, you have three times as many incidents as where something could jam. Something could be bobbled. You just increase the time for intervention. You increase the timeframe where kids can get out. And there's 11 kids out there today that are still running around on the playground pretty much now at lunchtime."

Lawmakers in Connecticut passed a series of gun control laws last week that limits the size of magazines to just 10 rounds and bans certain types of assault rifles, including the Bushmaster AR-15 that was used in the Newtown massacre. Lamakers in Congress have failed to make as much progress, largely drawing to a stalemate due to pressure from the nation's powerful firearms lobby.

This video is from "60 Minutes," aired Sunday, April 7, 2013.