I have a couple of questions regarding the actual slugs that have been recovered from the bodies.
Have they released any information at all other than to say that they are .223?  
Have all of them been .223?  Liberty86 posted an article which said that "most" were .223, is this true?  If so, what were the other calibers?
Do all of the recovered bullets match to one gun?  Is it even possible to ballistically match bullets in this situation?
Do we know if he/they are using FMJ, boat-tail ballistic tips, HP's?

I honestly don't think they are even sure it's a .223. There are several calibers in that range that it could be. They jumped on the .223, because it is used by "assault weapons", and is a "military round". I really can't see how there would be enough left of some of them after fragmenting to tell for sure. They said they have recovered brass, but I haven't heard them say,(officially), what it was. There's been a couple of good threads on the subject, but the search function is busted,(there is a conspiracy theory about that too).