How would I know one?
If they're a member of a State Defense Force or a State Guard and that state uses M4's, then why wouldn't they have one?
I thought there was a FReeper in the Texas State Guard that had one. I don't recall. I would have written it down had I know how important it was to you.
Out of 300,000,000 people in this country, surely SOMEONE fulfilling your criteria owns their own M4 legally. If you're so adamant about your criteria as to post so prolificly on a single topic, surely you could find _one_ person who enjoys that right as you so limit it.