I'm proud of Headstrong defending himself and taking the action needed to protect himself, but why is he not pressing charges?

The robber needs to be prosecuted to the fullest extent of the law. Most of the problem these days is the law doesn't deal with these people harsh enough, so they go out and do it again. The robber could have killed Headstrong, so why give him a break? He used a gun while committing a robbery. Throw the book at him!