I don't think the government will use force to go Orwellian. It will not be a physical war, which would be too costly, deadly, and pointless. They may go the way of Hitler and Stalin, but I do not think they will unless Americans do not relent willingly.
They will get Americans to disarm the same way they got the British to disarm. In one generation they will educate every American child to believe that guns are bad and that it is necessary to disarm for the good of the people.
It will be a psychological process, which is why watching too much TV isn't good. Government (public) schools are also a battleground. Kids are being brainwashed on every front.
How will assault weapons help? While they may not bring the war to you, it may be possible to bring the war to them. An angry, armed, organized group can shut down Washington (temporarily). Imagine the D.C. Sniper times 1000. I am not a military strategist, however, I don't think this is possible without assault weapons.
Any attack on this government is going to take balls and lots of them. LOL The renegades will also have to win the hearts and minds of the people first. They will have to know the U.S. military strengths and weaknesses. They will need an inside man. Without high powered weapons, I don't think any of this is at all possible. The troops must be sufficiently armed. But what do I know?
Btw I don't believe a revolution is likely to happen. Even with the current fears on gun control, I think "the administrators" want a peaceful transition. Unless someone will prosper from a revolution I don't think it will happen. They will wait for the generation that will gladly give up its guns.