My understanding of the BA13 is that the trigger mechanism is not independent of the action and it cannot be dismantled and put back in the, usually, obvious way. Which is why I have not had a go myself at adjusting the crisp but heavy (3 pound) pull. If you get around to doing the job could you set up a camera to record the process so that people like me can feel brave enough to have a go and not muck it up.
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