What Am I Riddles

Question: Turn us on our backs and open up our stomachs You will be the wisest. What am I?

Question: I shoot people and sometimes cut off their heads. What am I?

Question: I am made of scraps and rags, Yet when I am put together, I keep you warm in the winter. What am I?

Question: When you say my name, I am no longer there. What am I?

Question: Looking at my face, I'm no more than six.
Look at the rest of me and I'm 21.
You'll see my twin and me in Las Vegas.
Say my name and you'd be uttering a threat.

What am I?