And military-grade weapons are pretty rare here, requiring a huge amount of money and a lot of Federal permits and limitations. A simple "full-auto" sear for an AR-15 (to turn it into a select-fire M-16) costs north of $30,000, and it's impossible to buy any sort of actual assault rifle or carbine for less than $20,000 or so.
My rifles, pistols, etc are not here to stop petty crime, muggings, etc in some other part of the country. They're here to protect me and my family if things escalate, putting me and my family in danger, and (as everyone has noticed) the police can or will do nothing to stop it.
You guys sound like you're on your way down that road, from all you're saying. Do you really think that it can't possibly get out of control?
Remember ... "Hope is not a strategy!"