Actually, I didn’t count, but seven was pretty close. My TV was playing on one room and I was in another. All the sudden shots rang out, and I meediately knew the movie was Silverado. Which starts with a gunfight before a single word is spoken, and (I think) even before any theme music. In any case, I heard theme start up a few seconds later and it confirmed that the movie was what I thought. Besides the gunfire, there was the sound of feet on creaking boards (the gunman on the roof) and the sound of empty cartridge cases hitting the floor.
So, what other movies can be immediately identified at the start exclusively by sound effects?