Post mortum LE bolt failure...

[5thBatt]

Don't know why i bother replying to these threads as i just collect the bloody things but (& most probably a stupid question but please humor me) if there was enough pressure forced back under normal firing conditions that could violently force a cocking piece backwards though a pierced primer would you not expect a percussion cap to be blown off & hammer thrown back (or does this actually happen) every time you fired the likes of a old percussion Enfield??