A picture is worth a thousand words......
Admin edit: Images removed. Nice pictures, but it's easiest to follow the link below.. 
and so on and son and so on........still the baddest in the valley of death.......if there was any sanity in the brass insteadof the Pentagon Incorperated twits we would have never gone to the crappy m16 widowmaker hunk of junk.........many revisions and still no where near as tough and functional as an m14.
More here.....
http://www.imageseek.com/m1a/ 
I let my Rifle do my talking for me.