I like plastics and polymers as much as the next guy, but I've always wondered what an all-metal AR platform would be like. Granted, it would be significantly heavier, but it wouldn't be a crew-served weapon or anything. Would anyone like to guess how heavy such a rifle would be? What kind of metals could you use to make it as light as possible, without adding any polymer components? Before you say it's impractical, let me say this is only brainstorming.

Any thoughts are much appreciated!

P.S. Here's a song I'm listening to, thought I'd share it!

http://www.youtube.com/watch?v=u0yHQAA7XW8