I tested something I read online about a bug when shooting with scoped rifles, as the Tundra o the Mosin, and it turns out that when you aim directly to a target the shot is not isntantly released from the weapon but instead it releases when the recoil movement is already happening so the shot goes above the target. As you can see in this video.

https://plays.tv/video/5d028e26a06681c33b/recoil-bug-dayz-1-03