Nerdy shit about character: Chezikt
So She's non-canon since female skaven are all like, giant fuckslave breeders and Skaven lore (like most warhammer lore) is crammed full of racist/sexist imagry and tones.
Since the Jezzail fires warpstone (Skaven evil magictech rock stuff) shards I imagine the musket itself is rather inaccurate, but complicated magnification contraption we'll generously call a scope is what matters. The shot zigzags through the air, eventually hitting what ever was in focus.