Hey, that's cool, I've been thinking of making a 'primitive' crossbow as a good way to use wood that too short for a regular bow (I've got some short bits of Laburnum).
I made a repro 'light sporting crossbow' many years ago, and refurbed it recently...dunno if it's primitive enought for this forum (e.g. Steel bow).
It needs a bending lever to cock it as it 275lb draw weight
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Dunno if the video link will work...
Here's a close up of some of the inlay
Del