I've heard this from a lot of people, but it doesn't make sense to me. If you threw a loaded sten into a room and it went off, would the sear not catch the bolt after the first initial hit on the ground and stop it from going off again?
With an open bolt, fixed firing pin gun, the gun will fire continuously if the bolt is not caught by the sear. Disable the trigger mechanism, pull back the bolt, let it go, and the magazine will be emptied. Similarly, if the gun is loaded, bolt foreward, and the gun is jarred enough to move the bolt back far enough to pick up a round, but not far enough to engage the sear, the gun will fire one round.
With a Sten, if the sear is not under tension, it won't rise to engage the bolt. A broken tripping lever pawl could do this; so could a disengaged trigger/sear spring.
A dropped Sten with a defective or disabled trigger mechanism might dump its magazine, if dropped exactly the right way. The butt would have to hit the ground first, hard enough to move the bolt more than 2" to the rear. Pretty limited set of circumstances.
Now, stop and think about the sneaking up on the room full of Germans and chucking in a Sten. There is no way to guarantee it is going to fire. The is no way to guarantee it is going to inflict any casualties. Sneaking up to a room full of Germans would be a pretty stressfull, dangerous situation. So you are going to chuck in a loaded gun that might or might not have any effects? Rather than, say, a couple of hand grenades?




















































