I ran into rattlers often when I worked for the Game Department in Central Washington. I was a bit surprised how different they are dpending on where they live. The rattlers south of Moses Lake near the Potholes are usually barely 2 ft long, are generally light brown and the bios said they have an extra piece of gut to digest what they eat. I saw one up in the Sinlahekin that was close to 4 ft long and was greenish in color. I saw a mounted skin that measured 49 inches without the head.
I heard more than I saw. Never killed one.