FOX UNDERCOVER - The weapon Adam Lanza used on his rampage was a Bushmaster semiautomatic carbine, a military-style assault weapon.
This type of assault weapon could be bought in Massachusetts if it's altered to fit state rules, which means it cannot have a 30-round magazine, a pistol grip or a collapsible stock, according to a spokesman for the Massachusetts Executive Office of Public Safety and Security.
In order to have an assault weapon or other large-capacity firearm or a rifle or shotgun in Massachusetts, a resident must obtain what's known as a class A license, which make up the majority of licenses given out in Massachusetts: 261,121 in all.
The top five towns with the most large capacity licenses are Boston, Springfield, Plymouth, Worcester and Westfield.
The state could not tell us how many Bushmaster carbines are registered in the state.