Adult Historical Rom-Com, the reclusive hero has a passion for modifying pistols

[Pei]

A historical rom-com novel set in England during winter features a heroine who visits a reclusive hero's countryside estate ( for a specific reason). The hero has a passion for modifying and collecting pistols, and his dedicated workshop becomes the scene of their intimate encounter when the heroine finds him there.

Thanks a bunch for helping me unravel this!