When using a scope, it frequently happens to me that my crosshair is aimed above or to the side of a very close obstacle, but when I fire the shot is blocked. I’m guessing this is because the weapon is an actual 3D object, and the bullet originates from the muzzle, not your viewpoint.
I applaud the realism, but what’s not realistic is that I wouldn’t notice that I’m sticking my gun into a pile of rocks instead of aiming over. So in order to represent that, some sort of warning indicator when aim point and impact point are not identical would be appreciated.