Check out Carriage_Hill’s linked video here.
http://www.freerepublic.com/focus/news/2969802/posts?page=29#29
Then check out my response (LINK included), where the medical examiner says all wounds were caused by the AR-15.
You can see the police taking the weapon out of a trunk.
So he had a 223 rifle in the school and a shotgun in the trunk.