This is generally considered to be the first real submachinegun; saw service in the last months of the Great War. In the good old days, a shop in London ON had two for sale, @$125 and $135, complete with their snail drums. These are the ony ones I have personally handled and studied. The one illustrated in the Cruffler article is the modified version produced post WWI, with box magazine. Some were new production, others were originals with new magazine housings. Apparently the only reason the Luger snail drum was used on the WWI guns was because it was available. The original concept for use, with ammunition cart, etc. was ridiculous, in hindsight, but the guns did prove their utility during the last few months of the War. Surviving MP18/1s were still used for second line issue during WW2. The MP18, MP18/1 design eventually evolved into the MP28, which was the direct ancestor of the Lanchester, which in turn evolved into the Sten. The MP18 is quite portly, and the snail drum is awkward. But all the basic design features of the submachinegun were incorporated in the gun, and most first and second generation guns share these same features.