Some fans of THE DAY OF THE JACKAL (myself included) recall seeing an edit of the movie in which, when the Jackal visits the gunsmith to collect the rifle he uses it to suddenly kill him. In my case I recall this scene on a UK TV screening - I have never seen the film in the cinema as I was only 5 when it came out.
In the version currently and more widely seen the Jackal examines the gun and then asks for one of the explosive bullets. The scene then ends (with rather an abrupt cut) and that is the last we see of the gunsmith (a superbly observed perfomance IMHO).
The alternative edit we recall has the Jackal load the gun and shoot the gunsmith between the eyes - another victim claimed as the Jackal cuts off all links with the planned assassination.
The murder of the gunsmith does not appear in the book (in any case he has left incriminating evidence in just such an eventuality).