STEN submachine gun magazine - reverse engineered

grabcad

I was unable to find a good enough 3D model of the STEN submachine gun magazine, so I purchased one, and did my best to reverse engineer it by measurements. All dimensions are accurate to +-0.05mm or less, except some radiuses of the follower, which is a complex stamping and thus very difficult to measure, since the stamping process causes deformation that is not exactly as specification dictates. The model includes an example of the 9x19mm Luger cartridge, which I took from a old model, also based on caliper measurements, not specs. The position of this top cartridge is as measured with dummy round, and I also compared the measurements related to external cross-section, insertion depth stops, and locking cuts for the magazine latch with the dimensions from the book "Submachine gun designer's handbook" by G. Dmitrieff, and these coincide. Outside margins are maximum, so if you use this model in a new submachine gun design, any commercial STEN magazine should fit the magazine well and lock properly into position. If somebody has a better model of the STEN magazine, please let me know.