What type of gun the did Clint eastwood use in dirty harry?

The gun depicted in the film was a Smith & Wesson Model 29 .44 Magnum, which was in fact the exact same gun that was used for filming. However, there have been rumors that the nearly identical Model's 25 or 57 were used instead, due to lack of availability of the Model 29 itself and that of blank shots (which would have had to have been fabricated by the producers especialy for the 29.) In light of these rumors, it has been backed by several of the film's producers, including its co-writer, that the truly was "the most powerful handgun in the world," the S&W model 29 .44 Magnum. A side note, the handgun has since been surpassed by several later firearms as "the most powerful handgun in the world." Not to say that it couldn't do to one's self what Eastwood famously stated it could.