Firearm Anatomy - Book II The STEN Submachine Gun (Gun Design Series)

What David S. Findley did for the Thompson M1A1 SMG, one of the more complex firearms made, he does in this book for one of the simplest submachine guns, the lowly Sten MK2 submachine gun. From the production and design timeframe and production numbers, to the mechanical design and usable metallurgy for wartime production, and feed and magazine issues that were tolerated due to wartime needs of rearming the British Army in the days after Dunkirk. The gun was revolutionary for its efficiency and reliability in spite of its crude apperance and loose tolerances, done in record time in a day before CAD/CAM was even thought of. Mr Findley goes over the operation of the gun, along with a outstanding explanation of the fire control mechanism, in itself a clever piece of design, and provides one of, if not THE most accurate and complete set of blueprints for the firearm, including the stamped and folded sear. The usual calculations are shown for determining the cyclic rate, if you haven't a degree in any sort of enginering or mathematics, get a fresh cup of coffee and go on the the next chapter. Overall, a excellent reference book. I look forward to the next book in the series, I see the author at the top of form, with all his books destined to be collectibles in the future.

This book is very interesting. It is obviously written by an engineer who has experience on the subject . Being an engineer I do appreciate the format. It is very interesting and different. A WW2 Sten story, a simplified engineering analysis of sub machine guns and Sten drawings tied together by a book. The book give just a taste or jumping off point . It has been a pleasure to read. I’m glad that I purchased the book.

Good book.

Very nice analysis. However, some of the tables in the book show sloppy editing as the columns are inaccurate. Also the example spreadsheets in the back are not in an order that supports easy construction of your own spreadsheets and the calculations do not match the example in the text. This I found confidence shaking. Also, the referal to integral tables sent me on a search and there are several results for the integrals in question. Also, it would have nice if the data and formulas were provided on a cd as some software books offer. He references the software that he used but these are not cheap for the hobbyist. Overall though I learned a great deal.

Good book with numerous detailed drawings. I was looking for a source book for making a semi~automatic replica of the MkIIS version of this WWII CLASSIC. It was a great source of dimensions.

This book is great for reference. It's a 'must have'.

I've read a great many books on how to build homemade guns as a curiosity, but this one is very well put together. Not only does it possess and entire series of prints of every single part of a STEN gun, but it explains the principals and dynamics of how such arms operate. If there were academies of arms design and construction in the US, this could be used as a text book on a course about blowback arms. Much of this information is not easily found in other similar volumes, or on the internet.

Excellent! Very well explained with good plans and construction steps, totally recommended.

full of detail very good

This Book is a comprehensive guide for anyone interested in the design and manufacture of the Sten, including the "complete" engineering drawings and steel types/hardness ratings for information only, as it's illegal to build one, a very informative manual on a part of our history from WWII, well worth the price as a reference guide to fast design and manufacture under the pressures of wartime.

again for sure

Two notes: 1. the author ignores the history of firearms. he writes “ In the 1600’s, the wheel lock was developed and heralded the first use of firearms.” Indeed the wheel lock was already in production in the first years of the 1500’s (Braunshweig, 1507) while firearms, as individual weapons, were already in use at least since the second half of the XIV century. 2. the author ignores the comprehensive way how the “advanced primer ignition” works and limits his description to what Colonel Chinn wrote in his outstanding work on machine guns, i.e. the system with a movable firing pin actuated by a rotating cam just before the cartridge is fully chambered. As far as I know this system has been used in very few weapons, an excellent example being the Beretta 38A, while all others submachine guns obtained the same effect working on the length of the firing pin fixed on the bolt head. In Small Arms General Design written by D.F. Allsop and M.A. Toomey for the Royal Military College of Science, Shrivenham, UK (New Delhi, 2004), on the Blow back with Advanced Primer Ignition (API) as applied to sub machine guns, at pages 76-77 we can read what follows. When the weapon is cocked ready for firing the breech block is to the rear, held by the sear. The return spring is compressed thus storing energy. When the trigger is operated the sear is depressed and disengaged from the bent of the breech block which is driven forward by the spring. The face of the breech . block picks up a cartridge from the magazine, drives it forward and the nose enters the chamber. The round at this stage is angled across the breech block. As the cartridge feeds into the chamber, the continued forward movement of the block forces the round to align itself with the axis of the bore, and the cap is lined up with the fixed striker on the front face of the breech block. As soon as the friction force between round and chamber is sufficient, the cap is fired. The cap is thus fired while both the cartridge and the breech block are moving forward. The precise moment when the cap is detonated depends on a number of factors including: • Dimensions of the chamber and round. A chamber with the smallest permissible diameter and a cartridge case with the largest diameter will produce early firing, whereas a chamber on the largest permitted diameter and cartridge case on the smallest diameter could fire late. • Friction in the chamber. The better the finish of the chamber the later the firing will be given for a given dimension of cartridge case and chamber. As a broad approximation the bolt has some O.76mm to go before it encounters the breech face. The impulse given by the burning of the propellant causes a rapid slowing up of the forward movement of the breech block. When the maximum chamber pressure has developed as shown in Fig 6.3, the breech block is still 0.46mm clear of the rear face of the chamber and still moving forward. Thus while the bullet is still in the bore the breech block is either moving forward, momentarily at rest, or being driven slowly backwards. Since the cartridge case is parallel sided the breech will be fully obturated until the cartridge case mouth leaves the chamber. The further rearward movement of the block stores energy in the return spring and the breech block is then either held up on the sear or continues forward to complete the cycle of operations. This reciprocating movement of the breech block causes considerable changes in the centre of gravity of the weapon and also sets up vibrations when the case is being crushed up. The small sub machine gun as a class is unlikely to provide accurate fire. Experiments proved that the length of the fixed striker affects the rate of fire, the shorter the striker the higher is the rate. In a 9x17mm Parabellum calibre sub machine gun with a 0,8mm fixed striker it was obtained a 600 r.p.m. while with a 1,2mm length the rate of fire decreased to 510 r,p,m. So much observed, it must be remarked that the book is very well illustrated.