Gary Paul Johnston and Thomas Nelson's The World's Assault Rifles is always one of the first books we turn to for information on automatic rifles. At 1200+ pages, it's a huge tome and a massive amount of research went into it. Mr Nelson previously published two volumes on submachine guns and a book on assault rifles many years ago, but this current edition was heavily updated and republished just two years ago. The book is available in hardcover for us reference types and also as a Kindle edition for the tech-savvy on-the-go gun nut. Take your pick from Amazon: http://www.amazon.com/gp/product/0935554009/ref=as_li_ss_tl?ie=UTF8&tag=forgoweapo-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=0935554009 http://www.amazon.com/gp/product/B006YG6ZR6/ref=as_li_ss_tl?ie=UTF8&tag=forgoweapo-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B006YG6ZR6