A reposable surgical instrument includes a handle assembly (100) and an endoscopic assembly (200, 300, 400, 500, 600, 700) releasably engagable with the handle assembly (100). The handle assembly (100) includes a housing (110), a drive bar (132) supporting a ratchet pawl (142), and a trigger (122) coupled to the housing (110) and the drive bar (132). The endoscopic assembly (200, 300, 400, 500, 600, 700) includes a proximal hub (210, 310, 410, 510, 610, 710) including a ratchet rack (215, 415, 515, 615), an elongated shaft (220, 340, 420) extending from the proximal hub (210, 310, 410, 510, 610, 710) and supporting an end effector assembly(350) at a distal end (344) thereof, and a drive assembly (230, 320, 430) operably coupled to the end effector assembly (350). In use, movement of the trigger (122) from an un-actuated position towards an actuated position translates the drive bar (132) from a proximal position towards a distal position to engage the ratchet pawl (142) with the ratchet rack (215, 415, 515, 615) such that further distal translation of the drive bar (132) towards the distal position incrementally urges the drive assembly (230, 320, 430) from the un-fired position towards the fired position.