The scene in Kezar Stadium when he is aiming at Scorpio -- depending on your screen and equipment -- can make the barrel look awful long. I have sometimes thought that if they did insert an 8 3/8 in barreled revolver into the movie for "looks" it might have been here.

But personally, I think it's just a 6.5 inch barrel with a neat lens that makes it look so big.

Oh, and by the way, using the Canadian Stadium method of determining height and distance by the relation of the stadium seats to the upright posts that was originally invented by Neal Young and William Shatner at the Vancouver Winter Olympics, Eastwood is 6 foot, 3 and half inches in this photograph.