Iron Man, Vol. 1 #124 (1979)

Pieces Of Hate
Iron Man is hired to represent Tony Stark in negotiations to build a factory in the country of Carnelia. Things initially go smoothly, despite friction with Carnelia's representative (brought about by Tony's 9:30am drinking and Iron Man's crass attitude.) Things go much, much worse when Justin Hammer's people trigger Iron Man's repulsor ray and cause him to bore a hole through the ambassador, killing the man in front of hundreds of media witnesses.
Release Date: 1979