I started up a snake in the back yard a couple of weeks ago, and it looked harmless to me (round head and longitudinal yellow stripes) but the handyman working next door insisted it was a copperhead and killed it with a shovel. He made such a mess of it I didn't care to look for any fangs, since it was too late anyway.
Brother, I don't know and I'm not going to find out. The snakes I've killed were all cotton mouths/Moccasins (as I highly suspect this one was as well).
Pit Viper's are mean, mean, mean. Plus, they can strike at least the length of their body, and I believe some can strike 1.5 times the length of their body. I'm not going to take the chance with a BB or Pellet gun. It's double-ought buck or nothing for me.