In the movie, The American, Georgy Clooney modifies a rifle for a female assassin; later he realises this rifle will be used to kill him so he modifies it further without telling the female assassin.

When the female assassin pulls trigger this rifle fires backwards and mortally wounds her.

I understand Georgy Clooney is highly skilled gun smith but is it possible for him to reverse a rifle mechanism in such a dramatic way?