Get your copy from Collector Grade Publications: http://www.collectorgrade.com/bookshelf10.html
Collector Grade is known for being a premiere publisher of technical firearms reference books, and I would be willing to argue that "Sturmgewehr!" by Hans-Dieter Handrich is the best book they have yet printed. The book was originally printed inn 2004, and by the time I started looking for a copy myself, it was out of print and the price had jumped to at least $250, when I could even find a copy. I could never quite bring myself to pay that much, and so I was very excited when I learned that an expanded second edition was in the works. Well, that second edition is available now, and it's even better than I had anticipated.
What makes Sturmgewehr! such an excellent book in my opinion is how it tackles the story of the MP43/MP44/StG44 from several different angles in depth. It has the mechanical development of the gun from prewar experiments to the open-bolt MKb-42 trials guns to the production versions. But it also puts those guns in historical context, how they related to the other weapons being used by both Germany and other nations. It discusses how the design criteria of the Sturmgewehr were arrived at, in terms of logistics and manufacturing methodologies. It explains in detail the political disagreements and convoluted process of weapon design and adoption in Germany, including the three direct rejections of the concept by Hitler.
In short, it gives you the fully-rounded story of how the German military conceived and implemented a whole new class of small arms. In this way, it is really much more than just a book about a single gun's history - what you learn reading Handrich's work will give you insight into virtually all arms design programs of the 20th century, form the Chauchat to the 7.62mm NATO rifle trials to the SA80.
If you already have a copy of the original work, you will probably want this one as well, to get the addition 120 pages of information that have been added. And it should go without saying that if you don't have the original, you should absolutely get a copy of this new edition before it also falls out of print!
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