In the range of 8-12"
Found this one at work while I was cutting grass.
I thought I killed it
I'm not sure if I hit it or stepped on it or he might have already been hurt.
It's not common for them to be out in the open in the middle of the day.
I made a pass and when I was coming back up I saw him curled up. He had some blood on the left side of his face and wasn't acting like he was going to make it.
I took him in and got him cleaned up, held on to him for a couple days to see how he was going to do. A few days later he was doing awesome and eating.
He is a really cool snake but will musk the Hell out of you if he wants :p