When I was an apprentice I was told this as a matter of fact , that if a gun was perfectly jointed then it should be possible to tie it shut with a piece of string and to fire the gun without it opening .
I assumed that this was in the days of black powder and that no doubt some one had tried it. The proviso is " perfectly jointed" . I have done some silly things with guns over the years but this is one thing I would not do unless I was a good distance away and pulled the trigger with string .