The Day of the Jackal (1973)
A professional like this would know about 'eye dominance' and that switching eyes to aim can throw off the aim, substantially over a large distance.
This is another holdover from the novel. A master gunsmith would have known that hollow point or frangible rounds would perform the best for this role and neither would effect the ballistic performance of the round.
This is a holdover from the source novel and it's as incorrect there as it was in the film.