If I am reading the family tree correctly, Farouk's father only had two half brothers......Hossein Kamel and Tawfik Pasha. Farouks father Fuad I gained the throne when the son of Hossein Kamel (the above referenced Kamal el din?) refused the throne on his fathers death in 1917. I suppose the weapon likely belonged to both of them. If it did, it might explain how Kamal el din got the idea to regulate those MS sights out to 2000 yards in the link above.