A million dead chronographs can attest to the existence of this behavior.Kind'a reminds me of hearing about a guy (friend of a friend story) who decided to use the side of his pickup bed to steady his aim as he sighted his AR in at his backyard range. But he didn't do the math on the fact that the scope is raised and his target was slightly downhill. He managed to put several 5.56mm holes in the opposite side because the muzzle wasn't clearing that side of the truck even though the scope's line of sight was.