Well, I usually do medieval fantasy weapons, but this time I wanted to do a real weapon. The chosen one has been a weapon from first world war: The Lewis Light Machine Gun. I found it the other day and I liked its design, so I have decided to make a 3d version.
I always start looking for references. With this I not only find out about the details and general shape, but also about the purpose of the different components. This helps me understanding which ones need to be shown and how.
Once I have that I start by setting a scene with the most important references. When I have that I create a set of blocks with the general shape (silhouette). Then I start a set of interactions in which I go setting more and more details and refining shape: