Ok guys I decided that I want to make a custom FF tube for one of my AR upper projects. The thing is I'm not really sure where to start. Two of my friends have access to mills and lathes and all that crap and they are going to take care of actually making this thing come to life when it comes time. But before that even happens I got to  "design" this thing. I got a rough idea of what I want. But the hard part is getting it from my head onto paper, I got no skills in that area. I'm also not sure what the best metal to use would be. So I'm just looking for advise right now, on damn near everything.

Anyone have any advise for my nonskillz havin' ass?