don't know about this six months prison idea, but police forces in other civilized countries generally have a practice of retreating from dangerous situations, then containing them and ending them peacefully. See all the stories about how the German cops fired 85 bullets total in 2011. In the US we have this John Wayne Dirty Harry culture that tells police they are huge weaklings if they do that. They are trained and encouraged to end situations violently and "win" physically. If they do they are glorified. Equipping them all with military gear just amps it up to another level. I think as a society we could be every bit as safe if our police acted more like German police, but the police wouldn't get to beat up and shoot as many people.
When cops can order military vehicles and tanks to guard a pumpkin festival, their collective psyches are in bizarro places. In too many cities, the police are virtually above the law. They will not held accountable for what they do.
The fact that politicians cower and the NRA spends countless millions making them genuflect doesn't help either.