So you intend to shoot police officers ?
People rightly defend themselves against armed robbers. Most police would refuse to become criminals.
Well, all police are criminals against natural law, but within the context you're suggesting, I certainly hope you're right, but I'm not so sure. I think things would have to get pretty bad for them to stand up. If their masters said "go round up all the children and bring them to work camps" I believe many would take a stand, but tyranny doesn't usually work like that. It's more of a step-wise, tip-toe effect.
But if they said "Go get their guns, not ALL of them, just those really dangerous ones that they don't need for hunting and stuff" I think these guys will come and take them. My view can be skewed because I'm from NYC, I don't know. I have this notion that cops in more gun-friendly areas would be more likely to stand up, but it's just a guess.