You seem to be a bit more of a league beagle than I, so the assessment of the AK being brought to a high-ready position as being deadly conduct will drive this trial IMHO.
The article says the grand jury heard/saw evidence "including more than 150 exhibits and testimonies from 22 witnesses". Rightly or wrongly, the grand jury decided that Perry should be charged. Perry chose not to testify at the grand jury probably at the advice of his attorney. The next step is for him to be tried in court by his peers.
IMHO, there is a fine line between 'disorderly conduct' and 'deadly conduct' when it comes to carrying a weapon. Let's pray that fair-minded people sit as jurors and render a verdict based on evidence AND THE LAW - and not political persuasion.