Factual error: Even if the bullets were full metal jackets, the passing through Calvini's head and then the wooden column would deform them so the exit hole would be larger than the entry hole.
Factual error: If the two snipers were placed in the same building right on top of each other, and as far away from the target as we see, the difference in the angle of the two bullet trajectories would be very small. The difference shown by the plastic sticks would - at that long distance - mean a huge difference in height.
Factual error: There is not such a large souq (Arabic market area) in close walking distance to the Blue Mosque of Istanbul.