"So why is the AR-15 so appealing to mass shooters? To answer that question, it’s best to look at why the AR-15 is so popular in general... Essentially, the AR-15 is a versatile civilian-grade firearm that boasts ease of use, sheer firepower, and a certain cultural and aesthetic cache... Relatively inexpensive, readily available, highly customizable, and easily modified (whether legally or into a fully automatic weapon), the reasons for the AR-15’s popularity are apparent."